The Geology of Southern Zanskar Fuchs - 1987

Jb. Geol. B.-A. ISSN 0016-7800 Band 130 S.465-491 Wien, Dezember 1987

The Geology of Southern Zanskar (Ladakh) -Evidence for the Autochthony of the Tethys Zone

of the HimalayaBy GERHARD FUCHS.)

With 14 Figures und 3 Plates

HimalayaZanskar

Geological MappingStratigraphy

Tectonics

Contents

Zusammenfassung 465Abstract 466

1. Introduction 4662. Stratigraphy 466

2. 1. The Central Crystalline 4672. 2. The Phe Formation and Intrusive Granitoids 4682. 3. The Karsha Formation 4712. 4. The Kurgiakh Formation 4722. 5. The Thaple Formation 4722. 6. The Muth Quartzite 4732. 7. The Lipak Formation 4732. 8. The Po Formation 4742. 9. The Panjal Trap 4742.10. The Kuling Formation 4752.11. The Triassic Formations 4752.12. The Quartzite Series 4772.13. The Kioto Limestone 4772.14. The ~erruginous Oolite 4782.15. The Spiti Shales 4782.16. The Giumal Sandstone 4782.17. The Chikkim Limestone and Shillakong Formation 4782.18. The Upper Cretaceous Parts of the Lamayuru Formation 4802.19. The Stratigraphic Evolution of the Tethys Zone of Zanskar 481

3. Tectonics 4823.1. The Axial Depression of Lahoul 4823.2. The Relation between the Central Crystalline and the Sedimentaries of the Tibetan Zone 4833.3. The Structure of the Tibetan Zone in SE-Zanskar 483

4. Conclu~ons 487Acknowledgements 489References 490

ZusammenfassungDie Arbeit ergnzt die bereits von anderer Seite vorliegen-

den stratigraphischen und palontologischen Verffentlichun-gen durch die Geologische Karte von SE-Zanskar und beglei-tende Profilserien.

Hinsichtlich der stratigraphischen Entwicklung wirdbetont, da der mchtige schiefrig-sandige Basiskomplex derTibet-Zone eine typische flyschoide Beckenfazies dar-stellt. Die reichliche, rasche und rhythmische Sedimentscht-tung erfolgt in einem instabilen Senkungsraum. Ein 0 r 0 ge-ne s Ereignis, das zeitmig mit den k a led 0 n i s c hen Fal-tungsphasen korreliert wird, bringt einen scharfen Wechsel inder Sedimentation: In epikontinentalem Milieu werdenTransgressions-Konglomerate, reife Quarzarenite, Seichtwas-ser-Karbonate und lokal sogar Evaporite gebildet.

*) Author's address: Univ.-Doz. Dr. GERHARDFUCHS, Geologi-sche Bundesanstalt, Rasumofskygasse 23, A-1031 Wien.

E p i ro gen e Bewegungen an der Karbon/Perm-Grenzefhren zu teilweiser Erosion der palozoischen Formationenund transgressivem bergreifen des Perm. Diese Diskordanzsowie der begleitende Panjal-Vulkanismus werden mit demffnen der Neotethys in Zusammenhang gebracht. Das imPerm sich bildende F Iach m e er bestand im wesentlichendurch das ganze Mesozoikum. Mit der Mit tel k rei d e dif-ferenziert sich die Fazies in couches rouges pelagischerRcken und Plateaus, dunkle pelagische Kalke tieferen Was-sers, euxinische siltige Beckenfazies und sandig-tonigeFlyschschttungen. Die vielfltigen Vernderungen der Fazies-verteilung in der Oberkreide zeigen Unruhe, und da der N-Rand des Indischen Kontinents bereits nahe der Indus-Suturwar. Der orogene Umbruch begann in Zanskar erst imEozn.Te k ton i k: Es wird gezeigt, da das Zen t r a 1- K r ist a II i n

und die Basisserien der Tethys-Zone eine Einheit bil-den, die jedoch lokal wie im Raume von Padam gestrt seinkann. Durch eine Achsendepression in Lahoul ist das Zentral-Kristallin dort abgetaucht, Tibet-Zone und Chamba-

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Synclinorium sind in Verbindung. Einzelne Granitstcke in denSedimentserien von Lahoul stammen wohl aus dem darunter-liegenden Kristallin, sind aber mit diesem nicht identisch.Die von BAUDet al. (1982a,b, 1983, 1984) und GAETANIet

al. (1985) vorgeschlagene Gliederung der Tibet-Zone in einenStapel von Decken wird mit folgenden Argumentenabgelehnt:1) Im Sti'rnbereich der "Decken" kann an den angenommenen

berschiebungen in einigen Fllen der un gest r t ePrimrverband nachgewiesen werden.

2) Der "Deckenstapel" in S-Zanskar entspricht der nor ma-len stratigraphischen Abfolge vom Prkambriumbis ins Unter-Eozn. Lokal gestrte Formationsgrenzensind kein Beleg fr Deckenbau.

3) Zahlreiche Gnge von Pan j a I T rap in den palozoi-schen Formationen im Liegenden der Panjal Laven zeigen,da es sich um den pr im ren Untergrund und nicht umfremde tektonische Einheiten handelt.

4) Viele der angenommenen Deckengrenzen erweisen sichbei seitlicher Verfolgung als lokal gestrte Gesteins-grenzen, durchscherte Faltenschenkel oder Schuppungen.Fr tektonischen Ferntransport fehlt somit jeglicher Beleg,

und die Tibetische Zone ist in Bezug auf ihren Kristallin-Unter-grund sowie ihren Innenbau als autochthon zu betrachten.

AbstractThe paper presents the Geological Map and Sections of SE-

Zanskar, a supplement to the stratigraphical and palaeontolo-gical work done by other authors.Regarding the stratigraphical development it is

stressed that the thick monotonous argillaceous-arenaceouscomplex forming the base of the Tibetan Zone ist typicalfly s c h0 i d bas i n fa eie s. There was rich supply of sedi-ment and rapid, rhythmic deposition in an unstable, subsidingtrough. An 0 r0 gen ic event, which is correlated in age withthe Caledonian revolution, causes an abrupt change insedimentation: In epic 0 ntin e nta I environment transgres-sion conglomerates, mature quartz arenites, shelf carbonates,and locally even evaporites were deposited.Ep i r0 gen etic movements at the Carboniferous/ Permian

boundary cause partial erosion of the Palaeozoic formationsand transgression of the Permian. This unconformity and theassociated Panjal Volcanism are related to rifting and theopening of the Neo t e thy s. The shelf formed in the Permianpersisted throughout the Mesozoic. In the Mid die Cre t ace-ous the facies becomes diversified: Couches rouges form onpelagic ridges and plateaus, dark pelagic limestones in deeperwater, euxinic silty shales in basins, and sandy to shaly flyschin troughs rich in terrigenous detritus supply. The changes inUpper Cretaceous facies distribution indicate instability andthat the northern margin of the Indian Continent was alreadyclose to the Indus subduction zone. In Zanskar the orogenybegan in the Eocene.Tee ton i es: The Central Crystalline and the basal complex

of the Tibetan Zone belong to the same unit, although theirprimary connection may be disturbed, such as in the Padamarea. In the Lahoul axial depression the Central Crystalline iscovered by the sedimentaries, which are in connection fromthe Tibetan Zone via Lahoul to the Chamba Synclinorium.There are several granitoid intrusions in the sedimentaryseries of Lahoul; their source may be in the underlying crystal-line complex, but they are not identical with the Central Crys-talline.The suggestion that the Tibetan Zone represents a pile of

nappes (BAUDet aI., 1982a,b, 1983, 1984; GAETANIet aI.,1985) is rejected:1) In the frontal portions of the "nappes" several of the

"nappe boundaries" show undisturbed primary contacts.2) The assumed pile of nappes in southern Zanskar corres-

ponds to the normal stratigraphic Precambrian-LowerEocene sequence. Locally disturbed formation boundariesare not evidence for nappe structure.

3) The numerous dikes of Panjal Trap, which penetrate thePalaeozoic formations underlying the Panjal flows, provethat these series represent the primary substratum of thevolcanics - they are not another tectonic unit.

4) Many of the assumed nappe boundaries turn out to be justlocally disturbed formation contacts, sheared fold limbs, orwedge structures, if traced along the strike.

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Thus there is no evidence for thrusts over large horizontaldistances in the Tibetan Zone. Also in respect to the underly-ing Central Crystalline the Tibetan Zone is autochthonous.

1. Introduction

The complicated tectonic belt along the Indus - Yar-lung - Tsangpo was difficult to access for many de-cades. So, when India opened Ladakh for tourism,there began a rush of geological parties from manycountries to this region. The investigations concen-trated on the flysch- and molasse zones, ophiolite belts,and the melanges. I was particularly interested in therelations of the named zones to the Tibetan (Tethys)Zone with the aim to reconstruct the original facies pat-tern along the margin of the Indian Continent. 1976 onmy first traverse of western Zanskar I discovered theSpongtang Klippe (FUCHS,1977b) at a place whereLVDEKKER(1883) has indicated the occurrence of trapsamid of the Mesozoic sedimentaries. 1980 I mappedwestern Zanskar and came to the conclusion that in theSpongtang area thrust sheets deriVed from the IndusZone rest on the autochthonous to parautochthonousseries of the Tibetan Zone. French geologists (BAS-SOULLETet aI., 1978, 1980, 1983) active in the same re-gion accepted the northern carbonate belt of Zanskaras a higher nappe ("Zanskar-Shillakong Nappe"). Afterfurther studies there is agreement now that the area inquestion forms a fan-shaped anticlinorium as suggestedby me (1977b, 1979, 1982b).BAUDet al. (1982a,b; 1983, 1984) started work in

eastern and southern Zanskar and arrived at the sensa-tional result that the whole of the Tibetan Zone repre-sents a pile of nappes. As this allochthony concept wasin contradiction to all my experience from northernNepal, Spiti, and Kashmir, I visited the Markha-Nimal-ing area in 1983. To my surprise I found that faciesbelts bordering along tectonic planes in western Ladakh(Lamayuru Unit - Zanskar Carbonates) are still con-nected in eastern Ladakh. Thus the original transitionsof faciesfrom the shelf to the basin and to the subduc-tion Zone in the N are still recognizable there. Thepartly metamorphic sedimentary series overlying theTso Morari Crystalline in the Nimaling Dome representthe sequence of the Tibetan Zone ranging from the Pre-cambrian to the Paleocene (FUCHS,1984a,b; 1986). Allthat contradicts BAUDet aI., who assumed a series ofnappes there. STUTZ& STECK(1986) observed strongdeformation and shearing in the Nimaling sequence andtherefore follow BAUD assuming the existence of aLangtang Nappe. Certainly the sequence is disturbed,but in my view it is the chronological succession andnot a pile of tectonic units.Admittedly there may be some ambiguity to discern

whether a disturbed sequence is stratigraphic or tec-tonic, because nappes can show similarities and closerelations near their root zone (e. g. parautochthonousHelveticum and Helvetic Nappes in the Alps).In their frontal portions, however, nappes should be

distinct from each other and from their autochthonousbase. Therefore in 1985 I went to southern Zanskar,where BAUDand his co-workers describe the front oftheir nappes. There it should be possible to clarify theproblem whether the Tibetan Zone was allochthonousor not.


After the first reconnaissance work by STOLlCZKA(1865) and LVDEKKER(1883) geological research insouthern Zanskar was not taken up again before theseventies of this century. A series of reports were pre-sented by Indian parties (NANDA& SINGH,1976; NANDAet aI., 1978; RAINA& BHATTACHARVVA,1977; KANWAR&AHLUWALIA,1979; KANWAR& BHANDARI,1979; JOSHI&ARORA,1979; SRIKANTIAet aI., 1980). GUPTAdescribesmany fossil finds from this area (GUPTA& RAVI KAUL,1975; GUPTA & WEBSTER, 1980; GUPTA & JANVIER,1981; GUPTA& MICHALIK,1981; GUPTA& SHAW, 1981,1985; THAKUR& GUPTA,1983; WEBSTER& GUPTA,1984;GUPTA,1981, 1986). The Italian geologists team, partlyworking together with BAUD, presented a series of de-tailed accounts on the stratigraphy of southern Zanskar(GAETANIet aI., 1980, 1983, 1985, 1986; BAUDet aI.,1984; NICORAet aI., 1984; JADOULet aI., 1984; CASNEDIet aI., 1985).

Unfortunately they had no geological map as a basisfor their measured stratigraphic sections, only thegeneralized tectonic sketch map of Zanskar by BAUD.Inrespect to the general geology of Zanskar the stratig-raphers followed the views of BAUD (BAUD et aI.,1982a,b; 1983, 1984; GAETANIet aI., 1986). Accordingto this concept the observed sequence of formationsranging from the Precambrian up to the Paleocene isseen as a pile of "nappes". The fact that these "struc-tural units" are found in the original stratigraphic orderis explained by the assumption of decollements.Thus the present situation is the following: There

exists a lot of new stratigraphic information, but noadequate geological map - only the sketch map byNANDA& SINGH(1976). Therefore I understand my workas complementary:1) The geological map (PI. 1) and the geological sec-

tions (PI. 2) presented in this paper give the framefor the stratigraphic knowledge already existing.

2) Careful examination of the critical parts of the sec-tions, where BAUDet al. assume their nappe bound-aries, shall clarify the problem of tectonics, which isa principal one concerning the entire Tethyan Zoneof the Himalaya.

3) Investigation of the facies development in the Cre-taceous of southern Zanskar may help to completeour knowledge of the palaeogeography just beforethe beginning of the Himalayan orogenesis.

2. Stratigraphy2.1. The Central Crystalline

On our 1985 expedition the Central Crystalline wasmarginally touched in the Tsarap Valley between Icharand Padam. There it consists of two-mica augengra-nite-gneisses, nebulitic migmatites, grey and darkparagneisses (coarse-to fine-grained) containing garnetand sillimanite. This migmatite complex is frequentlypenetrated by aplite and pegmatite bearing tourmaline.Between Ichar and Padam the highly metamorphosedmigmatitic gneisses are overlain by slightly altered ar-gillites and siltites of the Phe Formation. There is agreat contrast in metamorphism and it is clear that thetwo rock units are separated by a tectonic plane, as al-ready stressed by BAUDet al. (1982 a) and GAETANIetal. (1985).

E of Ichar, however, the original transitional contactCrystalline/sedimentaries is still preserved: E of the vil-lage coarse-grained two-micaschists (:tgarnet andkyanite) become predominating, the gneisses graduallydisappear. Then further E the micaschists pass intophyllitic micaschists and dark phyllites intercalated withdark grey to violet quartzitic beds. SE of the impressiveSyncline of the Karsha Formation near Abnop the phyl-litic series grades into phyllitic slates with beds ofmetasiltstone and metasandstone, and SW of Purni fi-nally the metamorphism dies away. Thus there is a pas-sage from the Crystalline to the sedimentaries of theTibetan Zone, which from my experience from other re-gions of the Himalaya may be called a rule (comparealso GRIESBACH,1891, p. 209; HAVDEN,1904, p. 9-10;HEIM & GANSSER,1939; GANSSER,1964, 1983, p.33;SRIKANTlA,1981; BORDETet aI., 1971, 1975; HONEGGERet aI., 1982).

It is of great interest that further E in the traversesfrom Lahoul towards the N over the Bara Lacha La re-spectively Shingo La typical Central Crystalline, whichcan be traced continuously from the NEFA-Himalaya inthe E of the Rohtang Pass area in the W, forming thebackbone of the Himalaya, is interrupted in Lahoul.There the Rohtang Crystalline plunges towards the NWand the Crystalline of the Brahman-Zanskar Rangeplunges axially SE. This fact already known to LVDEK-KER(1883, see his map) is shown by alilater geologicalmaps (e. g. GANSSER,1964; FUCHS,1982c). In the axialdepression of Lahoul the sedimentary series of Spiti -Zanskar are connected with those of the Chamba-Kashmir Synclinoria. Therefore along the road from theChandra Valley to Darcha and the Bara Lacha La re-spectively the Shingo La most of the country rock be-longs to the Phe Formation. This thick argillo-arenace-ous complex shows varying grades of metamorphism,generally not exceeding greenschist facies. Alterationcommonly increases near granitoid intrusions (e. g.Jaspa Granite, Gumboranjan). Sedimentaries youngerthan the Phe Formation occur in synclines around BaraLacha La and at Tandi in the Chandra Valley. Therocks of the latter syncline are altered like the underly-ing series (POWELL& CONAGHAN,1973).

NANDA& SINGH(1976) termed the Central Crystallineof the Zanskar Range "Suru Formation" and distinguishfour members. The uppermost, the Darcha Member ac-tually belongs to the Phe Formation, which is intrudedby discordant granites. The Crystalline is separatedfrom the overlying sedimentary series not by a sharpboundary, but by a passage zone. A good portion of theCrystalline consists of altered sedimentaries and thebasal parts of the sedimentary succession have suf-fered slight metamorphism. From place to place thefront of metamorphism reached into various levels ofthe sedimentary column. In Lahoul and eastern Zanskarthe alteration dies away in the Early Palaeozoics,whereas in the Rangdum area of western Zanskar itreaches up high into the Mesozoic series. In view ofthis, it is meaningless to subdivide the Central Crystal-line into stratigraphic units, and as said above, it isdoubtful where to draw a boundary between Crystallineand sedimentaries. In this paper the high-grademetamorphics and the transitional zone are dealt in thechapter Central Crystalline, the slightly alteredsedimentaries and intrusive bodies are described in thenext chapter.

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2.2. The Phs Formationand

Intrusive GranitoidsAs the name Phe Formation (NANDA& SINGH, 1976)

is in common use, I keep to it, though no doubt the for-mation is identical with the Haimanta Formation of Spiti(HAYDEN,1904). The monotonous argillaceous-arenace-ous succession attains thickness of at least 2000 m. Itconsists of thick-bedded green to grey, massive-un-stratified or laminated sandstoneand siltstones alter-nating with green to dark grey, finely laminated siltyslates and slates occasionally being carbonaceous. Thesandstones are predominantly fine-grained, but thereare also medium-grained, micaceous sandstones, fine-conglomeratic layers, and clay gall' breccias. Petro-graphically the sand- and siltstones are immature,micaceous subarkoses (CASNEDI et aI., 1985). Thethick-bedded arenaceous rocks disintegrate to coarseirregular blocks. Characteristic are the laminated rockswith fining up units, current ripple cross laminations,lenticular, irregular, flasery and cross stratifications(fig. 1, 2). Flame structures at sandstone-slate inter-

Fig.4.Bulbous load convolutions in Phe Formation N of Purni.

Fig.3.Graded and current bedded metasandstone (light) and metasiltite (dark) ca.10 km S of Shingo La. Note flame structures in the central part of the photo.

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< /' :' '~~ _\}\'li;' "~" ..~}J f \.: /

~ ',~~\ }:' ./

1~"l~~-, f-- ,

--,~

Fig.1.Lamination and graded bedding in block of the Phe Formation. Note the trans-versal schistosity in the dark pelitic laminae.N of the Shingo La (cover of photo lens gives the scale).

L.~'~~~'Fig.2.Metasandstone to Metasiltstone showing lenticular flaser- and slight crossbedding. Units fining towards the top (near lens cover).Phe Formation, lower part of the valley leading from Kado Topko Valley toShingo La.

Fig.5.Load casts in fine-grained sandstones of Phe to Karsha Formation.N of Kurgiakh (lens cover for scale).

faces are not rare (fig. 3). Load convolutions ball- and-pillow structures, and beds disturbed by slumping arefrequent (fig. 4, 5). Also scour and fill structures are ob-served. On the s-planes of the sandstones varioustypes of flute casts, rill moulds, groove moulds, burrows

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Tectonics frequently caused small-scale folding ortransversal schistosity in the laminated rocks (fig. 1).The grade of metamorphism shows local variation.Epimetamorphic rocks predominate: Phyllitic slates,phyllites, metasandstones and -siltstones. Even if the

Fig.8.Flute casts in Phe Formation S of Purni.

Fig.10.Linguoid ripple marks not inconsistent with a flysch environment. The authorfinds these ripples reminiscent of the "sinuous, anastomosing pattern of rillmoulds", fig. 43 in DZULINSKY & WALTON (1965).Phe Formation between the villages Yal and Tetha.

Fig.9.Flute casts in the Phe Formation between the villages Yal and Telha.

and linguoid ripples are found (figs. 6-10). The ripples,which were also reported by BAUD et al. (1984) andCASNEDIet al. (1985), are of a type quite different fromshallow-water oscillation ripple marks.Considering the sedimentary structures, lithology,

great thickness and the vast areal extent of this type offormations throughout the Himalaya, deposition in abasin with flyschoid conditions is suggested (SRIKANTIA,1981; FUCHS,1982a,b, 1985). Thus I do not agree withBAUDet al. (1984), CASNEDIet al. (1985) and GAETANIet al. (1986), who assume a tidal flat environment withestuarine deposits. This assumption is inconsistent withthe large thickness. There was sufficient supply of sedi-ment, which was deposited in a rapidly subsiding insta-ble trough. The areal extent exceeds by far a tidal flat.There are clear indications of activity of turbidity cur-rents in a flysch environment, though these conditionsdid not persist necessarily throughout the formation (intime and space). The mudcracks and ripples cited asshallow-water indicators (CASNEDIet aI., 1985) may beexplained as pseudo-mudcracks (DZULYNSKI& WALTON,1965, p. 167) respectively ripples or sinuous anas-tomosing pattern of rill moulds (op. cit., p. 59, fig. 43) ina flysch environment.

Fig.7.Bulbous load cast and small flute casts.Phe Formation S of Char.

Fig.6.Flute casts in flysch sandstone.Block from upper Phe to Karsha Formation, N of Kurgiakh (lens cover forscale).

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grade of greenschist facies is exceeded the sedimen-tary structures are still preserved.The increase of metamorphism is easily recognized

on the descent from the Shingo La to Langkang, whichapparently was caused by the Gumboranjan Granite. Atthe northern foot of the pass the phyllitic rocks passinto phyllitic micaschists. Porphyroblasts of biotite (upto 5 mm thick) grow partly across the s. They are oftenamoeboid and filled with quartz grains showing internals, which was partly rotated. Metamorphic minerals arelight brown biotite, sericite, clinozoisite and tourmaline.The sedimentary lamination is still preserved. There arealso a few layers of amphibolite consisting of coarse-grained, green hornblende, some biotite porphyro-blasts, quartz, plagioclase, clinozoisite, apatite and ore;chlorite and sphene are of secondary origin.

E of the Langkang encamping ground, already veryclose to the Gumboranjan intrusion, the grade of altera-tion increases. Coarse-grained tw 0 -micas chi st scontain numerous grains of staurolite (up to 5 mm),which enclose quartz and ore; chlorite is secondaryafter biotite and staurolite. The micaschists bearingsmall quantities of oligoclase may pass into two -mic aparagneiss (:tgarnet). Both are interbedded withlight gneisses of 0 r tho type. It appears that thegneiss-micaschist alternation reflects the sedimentarysandstone-siltstone-slate layering of the Phe Formation.The orthogneisses have granitic compositon: Microc-line, somewhat perthitic, oligoclase, quartz, biotite,muscovite, subordinate apatite, garnet, zircon, ore andsecondary chlorite. Also in the described micaschist-gneiss series there are some rather rare amphiboliticlayers.The Gumboranjan Granite occurs as a small

boss in the centre of a domal structure. It is full of in-clusions of the country rock and does not form ahomogeneous intrusion rather a network of dikes andsills. First a generation of sills penetrated the countryrocks subparallel to their s planes, thus following thedomal structure. Then a more or less homogeneousmass of leucogranite intruded into the centre of thedome and swarms of dikes cut the country rock andolder sills in all directions. There are quartz-tourmalineveins, and predominating aplites and pegmatites bear-ing tourmaline, muscovite, garnet, traces of secondarycopper minerals and occasional beryl crystals of up to5 cm length. Frequently the dikes are composite show-ing banding parallel to the margins. The boundary tothe country rock is mostly sharp, in some cases, how-ever, where impregnations occurred, it is not very dis-tinct. The granite in the centre of the intrusion is a fineto medium-grained, light granite to aplite-granite poor inmica. Impregnations with tourmaline are common. A de-tailed study of the intrusion would reveal several gener-ations of veins and an interesting intru~ive history.As to the age of the Gumboranjan Granite SRIKANTIA

et al. (1980) suggested an Early Palaeozoic, whereasGAETANIet al. (1985) prefer a Late Himalayan age judg-ing from the lack of foliation and the composition of thegranite. To me these arguments seem very reasonableand I too think that the intrusion belongs to the group ofMiocene leucogranites widespread in the Himalayas.According to GAETANIet al. (1985) the Gumboranjan

Granite is faulted along its northern contact, which I didnot observe. After crossing the intrusive body themetamorphism dies away, the sills become rare and we

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are close to the Phe/Karsha Formations contact. Thusthe granite intruded in a high level of the Phe Forma-tion.From Darcha walking up the Kado Tokpo VaI-

ley in direction to the Shingo La after ca. 2 km one en-ters a huge g ran it 0 i din t r us ion. It appears that itrepresents the direct continuation of the Jas pa G ra-nit e, which was dated by FRANK et al. (1976)495:t16 m. a.With intrusive contact coarse-grained, massive

leu cog ran i te, bearing muscovite and tourmaline,borders the only slightly metamorphic Phe Formation,which builds up all the region of Darcha. This marginalfacies is followed by coarse-grained two-mica granitecontaining sporadic, idiomorphic phenocrysts of potas-sium feldspar (up to 5 cm lenght). There are also ir-regular dark patches rich in biotite. These patchesreach sizes of several cm and seem to indicate con-tamination. Under the microscope the granite exhibitshypidiomorphic structure. The rocks are almost free offoliation, but may be cataclastic. Perthitic mi c roc Ii neshows idiomorphic phenocrysts with Karlsbad twinningand oriented inclusions of plagioclase. PIag i0 c Iase(oligoclase) partly automorphic and zonary, enclosesnumerous flakes of sericite and patches of carbonate.Quartz frequently is undulaceous. Biotite is brownand contains sagenite and zircon. Muscovite andse r i ci t e are rather frequent. Accessory minerals arez i rcon, apat i te, and i Imen it e with leucoxen rims.Such porphyric and slightly hybrid granites build up

the area around the place Razik. Further upstream tothe tributary coming from Shingo La granitic andgranodioritic types are cropping out. In the latter thep Iag i0 c Iase predominates the mi c roc I i ne. It iszonary oligoclase to andesine, partly idiomorphic, andcontains sericite and clinozoisite. Brown bio tit e withsome sagenite; asccessories: zircon apatite; sec-on da ry minerals: chlorite, clinozoisite, and sericite.The structure is hypidiomorphic.The granitoid rocks along the Kado Tokpo Valley are

rather massive, only occasionally they are foliated.Higher up in the orographically left slopes of the valleythe light-coloured granitoids are seen intertonguing withthe overlying dark Phe Formation. There are inclusionsof the metasiltites in the magmatites measuring dm toseveral hundred meters, and there are numerous dikespenetrating the sedimentaries (fig. 11). There can be no

Fig.11.Granite of the Kado Topko Valley containing enclosure of metasiltite of thePhe Formation.


doubt the contact being intrusive. Besides inclusions ofslates and metasiltites also gabbroic and dioritic rocksare found in the granitoids. They are probably rocksfrom the first stages of differentiation of the magmaticbody. There are also fine- and coarse-grainedgranitoids penetrating each other.The trail leading up the tributary towards Shingo La

crosses the boundary between the granitoids and thesucceeding sedimentaries. In the orographically leftslope the contact is interlocking in decametric dimen-sions, on the right side elongate decametric bodies ofthe magmatites can be seen amidst the metasiltiteseries. It is evident there that the contact is intrusiveand not tectonic as interpreted by GAETANIet al. (1985).These authors mention that the lithology of thesedimentaries "may suggest an affinity with the PheFormation". However, I should like to stress that it isthe Phe Formation, which is continuous therefrom Zanskar via Lahoul to Chamba. The Tethyan Zoneis connected from Zanskar-Spiti to Chamba, thus weare in 0 ne tectonic unit not in serveral units makingup the "High Himalayan Crystalline" tectonically sepa-rated from the Tibetan Zone in the N. The granitoidsform discordant intrusions in this vast sediementarycomplex and do not represent the Central Crystalline(s. s).In the terrain built up by the Phe Formation

metadiabases and metagabbros are occasionally found.These form dikes, up to decamteric dimensions, penet-rating the Phe rocks unconformably. They seem to berelated with the extrusion of the Panjal Trap (see chap-ter 1.9.).Finally the age of the Phe Formation should be dis-

cussed. The formation is practically devoid of fossils.NANDA& SINGH(1976, p. 372) refer the finding of trilo-bites from the upper part of the formation, from theirThonde Member; from this member the authors alsomention the occurrence of grey carbonate rocks, thus Iinfer that the Upper Cambrian fossils are from theKarsha Formation. The Karsha Formation, no doubt,corresponds with the Middle- to Upper CambrianParahio Formation of Spiti (HAYDEN,1904). The under-lying Phe Formation correlates to the Haimantas. TheHaimantas pass into the Parahio Formation by alterna-tion, as does the Phe Formation into the Karsha Forma-tion. Therefore the Haimanta - Phe complex comprisesthe Cambrian up to its middle portion and mostprobably also Up per Pre c a mb ria n. THAKUR andGUPTA (1983) regard the Phe Formation Cambrian -Lower Ordovician. In my view this is too young becausein Spiti the Ordovician conglomerate transgresses onthe Haimantas and Parahio Formation with angular un-conformity (HAYDEN,1904; FUCHS,1982a).

2.3. The Karsha FormationThe name was introduced by NANDA& SINGH(1976)

for the thick alternation of argillo-arenaceous and car-bonate rocks succeeding on the Phe Formation. Theseauthors assumed Ordovician age, which from the abovesaid is very unlikely. THAKUR & GUPTA (1983) andGUPTA& SHAW (1985) report on ill-preserved trilobiteand brachiopod faunas and suggest Upper Ordovicianto Lower Silurian age. Like BAUDet al. (1984) I prefer aMid die to Up per Ca mb ria n age from analogy withSpitL

The lower boundary of the Karsha Formation is notsharply defined. I draw it with the first appearance ofcarbonate beds. The deposition of flyschoid dark greyto green slates, siltstones, and subarkoses persistedfrom the Phe into the Karsha Formation. The first car-bonate intercalations are thin (up to a few meters) andsporadic, but become abundant in the higher part of theformation. There we find algal reefs up to 200 m thick.The carbonates weathering in bright ochreous colourare predominantly light to medium grey, rarely green-grey dolomite. These very fine-grained to dense rocksare mostly massive and unstratified. However, locallyalso cm alternation of dolomite and shale was ob-served; in these cases the carbonate bands were fre-quently distorted to small scale boudins. The dolomites,particularly the riff complexes, disintegrate to huge ir-regular blocks. Stromatolites are not rare and figs. 12and 13, photographs from the top of the formation,show algal colonies resembling bread loaves.

Fig.12.Top of the Karsha Formation showing algal colonies resembling bread loaves(rucksack for scale).ESE of Tanze on the trail to Sinchan.

The flyschoid series interbedded with these shallow-water dolomites consist of green to dark grey and blackslates and phyllites, laminated, green, silty slates,siltstones, and fine to medium-grained micaceoussandstones. The latter are partly thick-bedded, partlyplatey. Sedimentary' structures observed are bulbousload casts, burrows, but also ripple marks. CASNEDIetal. (1985) and GAETANIet al. (1986) additionally record

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Fig.13.Close-up photo of stromatolites of fig. 12 (lens cover for scale).

cross-bedding, . mudcracks, bioturbation, patch reefsand peritidal structures. These authors found cycles ofshale, sandstone and dolomite and infer an environ-ment of tidal flat to coastal sands and peritidal carbo-nates. In my view the basin in which the Phe Formationwas deposited, was finally filled up. This is shown bythe increasing frequency and thickness of the shallowwater carbonates. In the uppermost portion of the for-mation, gradual increase of water depth is indicated(GAETANIet aI., 1986).The thickness of the Karsha Formation is estimated

about 800 m by GAETANIet al. (1986), whereas I thinkthat it may exceed 1000 m. There is uncertainty aboutthe primary thickness because of tectonic disturbance.The rigid reefal dolomite bodies within the ductile ar-gillo-arenaceous rocks led to much shearing along thedolomite boundaries.At Phuktal the top of the Karsha Formation consists

of slates, siltstones, light grey sandstones and thick-bedded, fine-grained light quartzites. Such quartzitesare not very characteristic of the Karsha Formation, andseem to be confined to the Phuktal area.In connection with the Karsha Formation it is neces-

sary to mention the occurrence of veins containing ore.In the Surichun Chu thick-bedded dolomite of theKarsha Formation forms the core of a secondary anti-cline (pI. 1, 2 [16, 17]). These dolomites are discor-dantly penetrated by serveral veins, up to 1 m thick.Prof. Dr. W. SIEGL (Montan. Univ. Leoben, Austria)kindly has made preparates of my samples and deter-mined the main ore minerals: chalcopyrite, pyrite, andtetrahedrite. By courtesy of Dr. O. SCHERMANN,Dr. H.NEINAVAIE (VOEST-Alpine AG, Eisenerz) kindlyexamined my samples also by microprobe. His resultsof two typical samples are presented:85/11/5: The ore consists predominantly of tetrahedrite, chal-

copyrite and subordinate cobalt glance. Pyrite occurssporadically. Malachite, azurite and Fe-hydroxyds aresecondary. The groundmass of the vein is composedof prevailing dolomite and some quartz.The cobalt glance occurs in xenomorphous toidiomorphous grains, with random distribution in thematrix and as fine inclosures in tetrahedrite; it is alsofound intergrown with chalcopyrite. Cobalt glance al-ways contains traces of Fe, Cu, and Sb as revealedby microprobe analysis.

85/11/7: The ore consists predominantly of tetrahedrite andpyrite, sporadic chalcopyrite, bornite, and covellite.Secondary ore minerals are azurite, malachite and

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Fe-hydroxyds. The gangue is composed frequently ofquartz (cataclastic and mainly recrystallized) and ba-ryte (particularly associated with tetrahedrite). Pyriteoccurs in xenomorphous to idiomorphous grains,which are often cataclastic and replaced by Fe-hyd-roxyd. The idiomorphous pyrite grains are mostly ob-served in tetrahedrite. The latter contains smallquantities of Fe, Zn and As.

In the above samples the tetrahedrite and chalcopyrite fillsinterspaces, joints up to 0,2 mm, and the intergranularies ofthe gangue minerals.

2.4. The Kurgiakh FormationCASNEDIet al. (1985) and GAETANIet al. (1986) use

the term Kurgiakh Formation for a flysch sequence, atleast 300 m thick, following on the Karsha Formation.They describe dark bioturbated pelites with layers ofnodular dolomite and basaltic tuffs in the lower part.The upper part is a "thickening - coarsening upwardmegasequence of thin-bedded greenish siltstonescharacterized by Tb-d Bouma sequences passing up-wards to thick-bedded, very fine-grained subarkoses.The Kurgiakh Formation records the transition fromshelf and slope sedimentation in poorly oxygenatedwaters to non-channelized distal turbidites. Thesedimentary evolution thus testifies active tectonic sub-sidence which largely exceeded sedimentation rates"(GAETANIet aI., 1986, 447-448). It is symptomatic thatthis geologist's group has mistaken the above flyschseries in the type area for the Phe Formation (BAUDetaI., 1984, fig. 8), though these authors deny the flysch-oid nature of the Phe Formation.The Kurgiakh Formation can be traced through-

out the Tanze-Chumik-Marpo area as a greenish ban.don top of the brown dolomite cliffs of the Karsha Forma-tion. The rocks of the Kurgiakh Formation are less re-sistant than the surrounding formations, thus they formsoft terrain frequently covered by talus. I observedgreen to dark grey, very fine slates and needle shales,frequently laminated, alternating with green to lightgrey, micaceous sandstones, mainly fine-grained; loadcasts, rill marks, tool marks etc. are frequent.This basin facies indicates a renewed subsidence

after the shallow-water carbonates of the Karsha For-mation. GAETANIet al. (1986, p. 447) report MiddleCambrian trilobites from the lower part of the formation,which shows that this subsidence occurred still in theCambrian. There is disagreement with GUPTA, whosuggests for each formation of the Lower Palaeozoic aconsiderably younger age (THAKKUR& GUPTA,1983).

2.5. The Thaple FormationNANDA& SINGH (1976) introduced this name for a

varicoloured, mainly red and brown formation, a markerhorizon from the Kurgiakh area of Zanskar to SpitL TheThaple Formation (some tens to 200 m thick, attaining300 m in the Chumik Marpo area) is composed of con-glomerates, quartzites, sandstones, carbonate sand-stones, slates and thin lenses of dolomite. The red,purple and brown con g 10mera te s prevail in thelower part of the formation. They are unstratified tothick-bedded, ill-sorted and contain moderately to well-rounded components up to 30 cm sizes; the latter arevaricoloured sandstones, quartzites and slates of the


same formation, and dolomites, limestones, phyllites,quartz, greenstone etc. from the beds underlying. Theochreous weathering matrix is arenaceous-calcareous.The conglomerates pass into conglomeratic sand-stones, red coarse to medium-grained sandstones,quartzites, carbonate-sandstones and quartzites.Cross-bedding and claygall breccias are very common.in these rocks, rarely ripple marks were observed. Ac-cording to GAETANIet al. (1986) the arenaceous rocksare predominantly Iitharenites. There are also' impureargillites and thin discontinuous cream dolomites. In theorographically left slopes of Chumik Marpo darkhaematitic quartzites crop out in the neighbourhood ofthe Muth Quartzite. As the rocks are vertical along afault there is some ambiguity whether the rocks belongto the Muth Quartzite or represent Thaple Formation -I favour the last possibility. The hard, thick-beddedquartzites are ill-sorted, moderately to poorly roundedquartzarenites rich in calcareous algae. The latter arefrequently replaced by haematite.In the Kenlung area (Yunan Valley) the Thaple For-

mation has lost the bright red colour due to metamorph-ism (greenschist facies).From the lithofacies and fining-up cycles GAETANIet

al. infer a subaerial, alluvial environment of alluvial fanto braid-plain (1986, p. 449). The Thaple Formationmarks a break in the sedimentary development: Aft~r along period of flyschoid basin deposition (Phe Forma-tion) a phase of shallowing caused by retarded subsi-dence (Karsha Formation) and renewed flyschsedimentation (Kurgiakh Formation) the conglomeratic,mainly terrigeneous beds of the Thaple Formationtransgress after a gap. In Spiti a marked angular un-conformity is found at the base of these conglomerates(HAYDEN,1904; FUCHS,1982a). There the purple con-glomerates and quartzites pass upwards into a mixedargillo-arenaceous carbonate series, which has yieldedCaradocian to Wenlockian faunas (HAYDEN, 1904;REED,1912). Thus the age of the conglomerates is de-termined as Ordovician in SpitL The orogenic phase in-dicated by the unconformity is further documented byan invasion of granites in the Himalaya dated by FRANKet al. (1976), MEHTA(1977), HONEGGERet al. (1982)and LE FORTet al. (1986). In Zanskar the fossiliferousOrdovician-Silurian sequence of Spiti overlying theconglomerates is missing, however THAKUR& GUPTA(1983) report on crinoids and trilobites from the ThapleFormation (their Tanze Formation). On the basis ofthese fossils they suggest an Upper Silurian-LowerDevonian age. Similar young age is proposed by GUPTA& SHAW(1985). In my view the break in sedimentationoccurred at the same time in Spiti and Zanskar: at theCambrian/Ordovician boundary. GUPTA'Sfossils, how-ever, may indicate that the conglomeratic facies per-sisted for a longer period in Zanskar than in SpitL Thusthe Thaple Formation would represent the Ordovicianconglomerates and Quartzites as well as the fossilifer-ous Ordovician to Silurian sequence of SpitLThe orogenic event documented by the Thaple For-

mation is related with the Pan-African orogeny accord-ing to BAUDet al. (1984), CASNEDIet al. (1985) andGAETANIet al. (1986). The 550-500 m.a. event in theHimalaya is interpreted by these authors as the lastpulse of the Pan-African Orogeny. Thus they disagreewith my concept of a Caledonian orogeny (FUCHS,1967) "on chronological and spatial grounds" (BAUDetaI., 1984, p. 184). There is apparently misunderstand-

ing of my views, because I never assumed a connec-tion between the Himalaya and the North-Europeanorogene but correlated in tim e. The granites clusteringabout 500 m. a. and the Ordovician conglomerates inSpiti-Zanskar mark an initial phase, because in otherparts of the Himalaya (Nepal-Kumaun, Kashmir) thebasin facies persisted through the Ordovician and thesignificant facies change took place in the Silurian. Theepicontinental Muth Quartzite (Devonian) signals theend of the Caledonian cycle.

2.6. The Muth Quartzite(STOLlCZKA, 1865)

The massive to thick-bedded, white Muth Quarzite isa marker horizon from Kumaun to Kashmir. In the areainvestigated its thickness .varies between 0 and 20 m,occasionally reaching a maximum of 50 m. The primarythickness seems to have been reduced, and by defor-mation the band of the Muth Quartzite was frequentlysqueezed.and distorted to lenticular bodies (e. g. nearTanze).The rocks are white to light grey, very hard

quartzites, massive or thick-bedded. They disintegrateto large irregular blocks, weathered surfaces beingcream coloured. Cross-bedding and oscillation ripplemarks are common; burrows were also observed. Forpetrographic details I refer to GAETANIet al. (1986,p.449).In the Chumik Marpo area sporadic beds of ochreous

weathering dolomite were found in the Muth Quartzite.Such carbonates accompany the quartzites in Spiti(FUCHS,1982a), Kumaun (HEIM& GANSSER,1939) andwestern Nepal (FUCHS,1977a).The Muth Quartzite was deposited in a stable envi-

ronment with a low rate of subsidence allowing re-peated recycling, which led to the superstable composi-tion and high grade of maturity.Generally the Muth Quartzite is poor in fossils. On

the basis of plants and faunas found in different partsof the Himalaya GUPTA(1973) and THAKUR& GUPTA(1983) assigned a Middle to Upper Devonian age.

2.7. The Lipak Formation(HAYDEN, 1908)

In the investigated area the Lipak Formation consistsof grey, dark bluish grey and black limestones, dolo-mitic limestones, sandy siliceous limestones and marlsand light-coloured evaporitic series in the upper part.The thickness varies between 25 and 250 m, probablydue to the mobility of the evaporitic rocks. The carbo-nate sequence is always well-bedded-platey to thick-bedded with even or nodular s-planes. The individualbeds often show fine lamination, slightly lenticularstratification and intraformational breccias. Crinoidallimestones and shell beds are very common. The lattercontain brachiopods and bivalves.The rich fossil content of the Lipak Formation is refer-

red by THAKUR& GUPTA(1983) and most recent findsare recorded by WEBSTER& GUPTA(1984) and GUPTA(1986). A Lower Carboniferous age of the LipakFormation is well-established. In the lowermost carbo-nates following immediatelyon the Muth Quartzite how-ever, GUPTA(1986) discovered an upper Upper Devo-

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nian (Fammenian) conodont fauna. Thus the changefrom arenaceous to carbonate deposition took place inthe uppermost Devonian, similarly to Spiti (HAYDEN,1904; FUCHS,1982a, p. 338).Regarding facies of the carbonates GAETANIet al.

(1986) infer a "shallow subtidal environment, possiblyan open to restricted carbonate shelf" (p. 451).The gyp sum fa ci e s in the upper Lipak Formation

is of much interest: It commences with ca. 10m ofblackish limestones alternating with red shales, pinklimestones and brown to cream shaly marls. The carbo-nates are micritic-detrital, pelletal or sandy limestonesshowing numerous shells of ostracods. GAETANIet al.(1986) record ostracods, crinoids, brachiopods,bivalves, and gastropods from this lower part; one ofthese fossils Tomiproductus ranges in age from MiddleTournaisian to Early Visean.Then follow basic volcanic rocks and the first gypsum

layers. The volcanics are concordantly interbedded,green-grey, schistose rocks. The fabric is fine-grainedophitic with numerous patches of carbonate, which arepartly enclosures of the syngenetic carbonates partlyamygdales filled with carbonate. Around these carbo-nate patches the plagioclase laths are arranged parallelto the boundary. The components of the metavolcanics- lavas to tuffs - are idiomorphic plagioclase, chlorite,carbonate, ore, and small quantity of quartz.Above these volcanics the main mass of white,

coarse-grained gypsum follows, several tens of m thick.Interbedded with the gypsum we find pink limestone.These carbonates are micritic-detrital, pelletal, showingstrong bioturbation. Crinoidal and algal remains are fre-quent.Above the evaporitic series we find well-bedded car-

bonates like the lower part of the Lipak Formation.There may be a repetition by folding or the facies re-turned from evaporitic to carbonate shelf conditionsnear the top of the formation.

2.8. The Po FormationHAYDEN(1904) introduced this name for the thick

shale-quartzite series overlying the Lipak carbonates inSpiti.' In the investigated area of southern Zanskar thePo Formation is 200-300 m thick, locally it may attaineven 400 m. The formation is a thick-bedded alternationof quartzites, sandstones, siltstones, slates, and impurelimestones. The hard quartzites are white, grey, greenand break into large irregular blocks. The green, grey,and brown sandstones and subarkoses show currentbedding and uneven s-planes. They may containsporadic mud-supported well-rounded pebbles and cob-bles. Greenish siltstones pass over silty shales intoblack slates, often disintegrating as "needle shales".The dark argillites exhibit bleachig on weathered sur-faces. The grey to blue limestones are mostly impureby silt or sand content. Brachiopods, crinoids, and gas-tropods are sometimes observed. Burrows and otherbiohieroglyphs are not rare. GAETANIet al. (1986)suggest a shallow epicontinental shelf environment forthe lower part of the formation, more proximal deltaicdeposition for the upper portions.Different stratigraphic subdivisions of the Carbonifer-

ous are used by SRIKANTIAet al. (1980) and THAKUR&GUPTA(1983). In the present paper the term Po Forma-tion assigns the clastic series between the underlying

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Lipak Formation and the transgressing Panjal Trap. Theconglomeratic quartzites and black slates immediatelybelow the panjal Trap, however, are excluded from thePo Formation and belong to the transgressing Permianseries. This is shown by the fact that the conglomeraticquartzite accompanies the trap irrespectively what for-mation is underlying.The age of the Po Formation is Middle and Upper

Carboniferous on the basis of the fossil content referredin literature.

2.9. The Panjal Trap(RalakungFormation,NANDA & SINGH, 1976)

The dark band of the Panjal Trap is a conspicuousmarker horizon in the landscape of southern Zanskarand can be traced also on satellite imagery. The PanjalTrap rests with an angular unconformity on various old-er Formations (Karsha to Po Formation). This conspi-cuous unconformity was rightly recognized as stratigra-phic by NANDA& SINGH(1976), but recently misinter-preted as nappe boundary (BAUDet aI., 1982a,b, 1984).The base of the Panjal Trap is formed by a 8 to 10m

band of thick-bedded quartzite with partings of blacksilty argillite. The very hard quartzite is white, green,or grey, fine- to coarse-grained with conglomerate tobreccia layers. The components of the latter reach 3 cmsizes and show rounded to angular shapes. They con-sist of white quartz and dark grey to black quartzite andslate in light quartzitic matrix. The quartzite showsunder the microscope angular grains of quartz, fine-grained quartzite, tourmaline, zircon, ore and flakes ofwhite mica in a predominantly siliceous groundmass,which is generally subordinate. The quartzite is mode-rately to well-sorted, frequently cross-bedded andshows fining up units. The interlayered argillite is black,silty-micaceous shale. At the top just beneath the Pan-jal Trap the uppermost dms of the sediments are darkerand hardened under the influence of the magmatic con-tact. In thin-section it can be observed that thegroundmass has recrystallized with growth of chlorite,sericite, and sphene. In the section NNW of Tanze,where I met the above beds for the first time, the litho-logy is not so much different from the underlying PoFormation. But I observed that this quartzite band over-lapped different beds of the underlying formation. ThenI found the conglomeratic quartzites at the base of thePanjal Trap at Phuktal and in blocks in the Thongdearea, where the Po Formation is missing. Thus it is evi-dent that the quartzite band marks the Permian trans-gression so widespread in the Himalayas (W-Nepal,FUCHS,1967, 1977a; Kumaun, HEIM& GANSSER,1939;Spiti, HAYDEN,1904; FUCHS,1982a). It should be stres-sed that the lower contact of the quartzite to the PoFormation is a stratigraphic one, the upper to the flowsof the Panjal Trap is a magmatic contact, both bound-aries being undisturbed by tectonics. BAUDet al. (1984,fig. 2, 10) assumed a thrust separating their Pughtal-and Zangla Units at the base of the panjal Trap.GAETANIet al. (1986, fig. 5) draw this nappe boundarylower down within the Po Formation or at its base. Ac-tually none of these envisaged thrusts does exist.The Pan j a I T rap consists of green basaltic rocks

weathering into sharp-edged blocks. According to HON-EGGERet al. (1982) the traps are mainly silica-saturatedor nepheline normative basalts of the tholeiitic or al-


In western and northern Zanskar the Triassic is re-presented by an approximately 1000 m thick sequenceof limestone, dolomite, and shale. This succession israther uniform and does not show distinct litho-unitssuitable for subdivision. It is difficult even to separate

2.11. The Triassic Formations

2.10. The Kuling Formation(STOLlCZKA, 1865)

The formation varying in thickness betwen 20 and50 m is composed of quartzite, sandstone, impurelimestone, and silty shales. Thick-bedded white, greyand brown, coarse-grained quartzites dominate in thebasal part of the formation. They also contain breccialayers. Associated with the quartzites we find green-grey impure micaceous sandstones. These rocks aresucceeded by brown weathering, green-grey, medium-grained carbonate sandstones, -quartzites, greyarenaceous limestones and blue-grey marly limestonesand shales. The upper portions of the formation consistof dark silty, micaceous argillites with sporadic blacknodules, a series well-known in the Tethys Zone underthe name Kuling Shales. NICORA et al. (1984) give amore detailed description of the Kuling Formation, towhich I refer.The Kuling Formation is very rich !n fossils and they

are found throughout the formation. Brachiopods, bryo-zoans, corals, gastropods, bivalves, and echinodermsare found. Near the top the first ammonoids occur. TheKuling Formation following the panjal Trap seems to bemainly Middle and Upper Permian (SINGH et aI., 1982)whereas in the E, where the Volcanics are missing, theformation comprises the whole of the Permian (JOSHI &ARORA, 1979; THAKUR & GUPTA, 1983, 15-16). ThereGUPTA uses the local term Sarchu Series.The environment of the Kuling Formation was shal-

low-water. It is a transgressive series like the basalbeds of the Panjal Trap Formation. These effusionsseem to be related with rifting, which led to the openingof the Neotethys (ANDREWS-SPEED& BROOKFIELD,1982;HONEGGERet aI., 1982). The transgressive sequence ofthe Permian reflects this break up and the followingsubsidence (BAUD et aL, 1984; GAETANI et aI., 1986).

... ~ for instance N of Phuktal, shows the connection of themafic dikes with the Panjal volcanism. GAETANI et aL(1986, 454-455) studied some samples of the maficdikes and found them to compare well with the PanjalTraps. It is surprising that inspite of these facts BAUD etal. (1984) and GAETANI et al. (1986) think the PanjalTrap as belonging to their "Zangla Nappe" separatedby a thrust from the underlying formations ("PhuktalNappe"), which are cut by the mafic dikes. In my viewthe observations only allow the conclusion that, whenthe flows of the trap extruded, the underlying forma-tions were penetrated by numerous dikes from thesame magmatic source. Besides the undisturbed con-tacts this is another evidence that the Panjal Trapforms 0 n est rat i g rap h i c succession with the under-lying Palaeozoic formations.

kaline series. There are thick-bedded series of flowsshowing very fine-grained chilled margins and beingmedium- to coarse-grained in the central portions of theflow. Pillow structures are sometimes to be found. Vesi-cular rocks are common, the amygdales filled by chlo-rite, epidote, quartz, calcite etc. Further cm-wide gaspipes are found perpendicular to the margins of theflow. Structures due to lava flow, such as ropy lava, arenot rare (fig. 14). Agglomerates and other pyroclasticrocks are generally multicoloured - red, green, andpurple. The components reach dm sizes. Interlayered,and particularly at the top, purple and green tuffaceousslates are associated with the traps. For details of pe-trography and geochemistry I refer to SINGH et al.(1982) who studied the Panjal Trap of Zanskar particu-larly.

The thickness of the Panjal Trap in Zanskar - ap-proximately 300 m - is small compared to thethousands of meters in Kashmir. In the Lingti Valley thePanjal Trap pinches out towards the E.NANDA& SINGH (1976) and SINGH et aL (1982) report

on fossiliferous limestones interstratified with the trap.On the basis of the fossils a Lower to Middle Permianage is proved for the Panjal Trap of Zanskar (THAKUR&GUPTA, 1983).All the older formations underlying the Panjal Trap

are penetrated by swarms of basic dikes. Their thick-ness varies from one to tens of meters. Increased fre-quency of the dikes near the Panjal Trap, as observed

Fig.14.Ropy flow structures in block of Panjal Trap, E of Thongde Gompa.

475


the Kioto Limestone from the underlying Triassic beds,if the Quartzite Beds are missing. Additional difficulty tosubdivide arises from the tight folding of the sequence.Thus on a reconnaissance survey I used the term Trias-sic-Jurassic Carbonates (FUCHS, 1982b) or Zanskar-Carbonates (1986) for this series.InSE-Zanskar, however, the litho-units known from

Spiti are more and more recognizable. The subunits areindicated in the map (pI. 1) and sections (pI. 2) intraverses along the Shingri- and Tsarap Chu.In recent papers the old term "Lilang" has come in

common use again. BAUDet al. (1984) and GAETANIetal. (1986) use the name Lilang Group in the sense ofHAYDEN(1908) for the Triassic sequence from the baseup till the Kioto Limestone. SRIKANTIAet al. (1980) in-clude also the Kioto Limestone. The latter seems pre-ferable to me, because on satellite imagery or bybinocular observation from afar the carbonate belt canbe traced only as a whole.

2.11.1. The Tamba Kurkur FormationSRIKANTIAet al. (1980) introduced this name for a

very distinct Iithounit traceable from Nepal to Zanskar.It is relatively thin, generally less than 50 m - W of theZanskar River it reaches 100 m according to NICDRAetal. (1984) and GAETANIet al. (1986). Composed pre-dominantly of well-bedded limestone the Tamba KurkurFormation can be followed as a thin resistant band inthe scenery.The formation starts with a thin-bedded alternation of

grey, dense limestone and grey shale. Some limestonebeds abound in ammonites, which are commonly muchdeformed. The central parts of the formation are thick-bedded to massive forming escarpments. They consistof grey to bluish, frequently nodular limestone, ratherbarren in macrofossils. The upper part of the TambaKurkur Formation is composed of thick-bedded, darkgrey to blue nodular limestones with some shale part-ings. They are rich in Anisian ammonites. BAUDet al.(1984), NICDRAet al. (1985) and GAETANIet al. (1986)show by means of conodont faunas that the Scythian/Anisian boundary is in the upper part of the centralmember. The Tamba Kurkur Formation comprises theScythian and Anisian in Zanskar, in Spiti it reaches intothe Lower Ladinian accordig to DIENER(1912, p. 71)and KRYSTYN(FUCHS,1982a).As to the environment GAET~NIet al. (1986) suggest

"pelagic sedimentation in upp~r bathyal condition withlow sedimentation rate" (p. 457), which agrees verywell with my views (FUCHS,1967).

2.11.2. The Daonella ShalesAt the top the limestones of the Tamba Kurkur For-

mation become marly and are increasingly interbeddedwith shale. Thus there is a passage into the succeedingDaonella Shales (ca. 40 m). These consist of softearthy-coloured shales, marls and dark mudstones,which are generally much contorted and covered bytalus. HAYDEN(1904), DIENER(1912) and GUPTA(1975)assign Ladinian age to the sporadic fossils. TheDaonella Shales correlate to member 1 of the HanseFormation of GAETANIet al. (1986). The fossils found bythe named authors (p. 459) fit well with this correlation.

476

2.11.3. The Daonella LimestoneAbove the geomorphologically soft terrain of the

Daonella Shales the well-bedded Daonella Limestoneforms cliffs several tens of meters high. It consists ofdark grey, blue, and black limestone partly nodular, andsubordinate black marls and shales. The name-givinglamellibranchs are rather frequent (e. g. on the trailfrom Sinchan to Phirtse La).In Spiti the Ladinic/Carnic boundary is assumed

within this limestone series (HAYDEN,1904). In Zanskar,however, BAUDet al. (1984) and GAETANIet al. (1986)report Late Ladinic ammonite faunas from the upperpart of their member 2 of the Hanse Formation, whichcorresponds to the Grey Beds of SpitL Only the lowerpart of member 2 correlates to the Daonella Limestone.Thus there is ambiguity whether the age of the GreyBeds in Spitl. should be revised to be Late Ladinic or achange in lithofacies should be assumed.

2.11.4. The Grey BedsAbove the Daonelle Limestone marly and argilla-

ceous rocks become predominant. Like the two underly-ing formations the sediments are of dark colour and arebleaching light grey if weathered. The sequence of thin-bedded shales, marls, and limestones is much de-formed. The thickness of the Grey Beds - less than100 m - is much smaller than in SpitL The Grey Bedsare regarded as Carnic in Spiti (HAYDEN,1904; DIENER,1912). The lithologically corresponding series inZanskar has yielded a Late Ladinian fauna (BAUDet aI.,1984; Gi~TANI et aI., 1986).The argillaceous-calcareous sequence succeeding

the Tamba Kurkur Formation is deposited on pelagicouter shelf (GAETANIet aI., 1986). The uppermost partof the Hanse Formation (member 3) of these authors in-dicates transition to shallow water carbonate environ-ment. This member 3 corresponds to the lower portionsof the Tropites Limestone, which f9110wSon top of theGrey Beds. GAETANIet aI., suppose their member 3 toreach into the Carnic, which fits well with the abovecorrelation.

2.11.5. The Tropites LimestoneIn Spiti a 250-300 m carbonate succession forms a

marked cliff above the soft Grey Beds. HAYDEN(1904)named the series Tropites Beds and I used the termTropites Limestone (FUCHS,1982a) for this very distinctlitho-unit.Like in Spiti the Tropites Limestone shows tripartition

in eastern Zanskar (Tsarap Valley N of Phuktal):1) The lowest member consists of dark thick-bedded

limestones and dolomites.2) The middle member is distinctly sandy and weathers

in brownish colour. It is composed by a thick-beddedalternation of grey sandy limestones and dolomites,calcareous and dolomitic sandstones, and fine-grained light sandstones and quartzites. Cross-bed-ding, intraformational breccias, scour and fill struc-tures, oolites, crinoid and shell layers suggest shal-low-water deposition. Fine-lamination, partly graded,is common; burrows were observed.

3) The upper member consists of thick-bedded dolo-mites and limestones.


The Tropites Lim~stone is approximately 300 m thickand rather poor in fossils. On the basis of the fossilsfound HAYDEN (1904) and DIENER (1912) regard theTropites Limestone as Carnic. In the nomenclature ofBAUD et al. (1984) and GAETANIet al. (1986) member 3of their Hanse Formation and 'their Zozar Formationseem to correlate to the Tropites Limestone. GAETANIetal. found a fauna of megalodontids at the top of theirZosar Formation, which according to them may suggestNoric age. It should be noted, however, thatmegalodontids occur already in .the Carnic. GAETANI etal. (1986) regard the series as regressive, a transitionfrom subtidal inner shelf to interior platform/tidal flat(p. 461).

2.11.6. The Juvavltes and Monotis ShalesFrom Nepal to Kumaun, Spiti, and Zanskar the Noric

is characterized by shaly-silty-arenaceous beds beingpredominant or alternating with limestone: TarapShales, Kuti Shales, Juvavites-Monotis Shales etc.From the E towards the W the carbonate content in-creases and in western Zanskar and Kashmir finally theNoric is calcareous-dolomitic. In the region of the upperZanskar River the Noric seems to lose its distinctcharacter towards the NW. In parts of Spiti the Noric isdivisible into the lower Juvavites Shales and the upperMonotis Shales by a marker horizon - the Coral Lime-stone (HAYDEN, 1904). Where the latter is missing thelower and upper shale series are difficult to separate. Asimilar situation is in Zanskar:The Tropites Limestone issucceeded by a

100-200 m alternation of nodular, partly thiqk-beddedblue limestone, green, grey to plack, silty slates,siltstone, and impure, fine-grained sandstone. Flasery,lenticular stratification, and cross-bedding are common.As to the fossil content I refer to HAYDEN (1904),DIENER (1912), GUPTA (1975), and GAETANI et al.(1986).

BAUD et al. (1984) and GAETANI et al. (1986) desig-nate only one formation - the "Quartzite Series" - be-tween their Zosar Formation (Tropites Lms.) and theKioto Limestone. Though BAUD et al. (1984, p. 181)refer to HAYDEN (1904) in using the term '~QuartziteSeries", it is clear from their description that the seriescomprises both the Monotis-Juvavites Shales (HAYDEN,1904) and the Quartzite Series (HAYDEN, 1904).GAETANIet al. (1986) discern two litho-zones and it is ofgreat interest that on the top of the lower one they re-cognized a coral horizon (lithofacies d). It is verysuggestive to correlate these "small coral boundstones,occasionally reaching plurimetric size" (p. 462) to theCoral Limestone of Spiti. Thus their lithozone A seemsto correspond with the Juvavites Shales, lithozone Bwith the Monotis Shales. In these series the arenace-ous beds are mostly fine-grained subarkoses. TheQuartzite Series in the sense of HAYDENstart with the"medium grained quartzarenites::with subrounded butmoderately sorted grains" below the boundary with theKioto Limestone (p. 462). To the same horizon BAUD etal. (1984, p. 181) refer by noting quartzarenites "con-fined to the top of the unit and to the base of the over-lying Kioto Limestone". Thus their "Quartzite Series",being ca. 300 m thick, represents HAYDEN'S Monotis-and Juvavites Shales and only the uppermostquartzarenites may be correlated to HAYDEN'SQuartziteSeries. This discussion was necessary to remove the

confusion in nomenclature arising from the above useof the term "Quartzite Series".

Regarding environment there is a marked increase interrigenous influx in the Noric, which may be tracedthroughout the Tibetan Zone. GAETANlet al. (1986,p. 463) infer "deltaic systems in an inner shelf becom-ing more diversified upwards (channels, bars)".Along the strike the facies of the Noric beds changes

from flyschoid basin conditions in Nepal to shallowwater in the western Himalaya.

2.12. The Quartzite SeriesBetween the underlying shaly-silty-arenaceous-cal-

careous alternation and the Kioto Limestone thick-bed-ded quartzites form a marker horizon throughout theTethys Himalaya. In Zanskar, however, the ..QuartziteSeries is not as well-developed as in other regions. It isa few tens of meters thick only or may be missing at allin some sections. Characteristic are the thick-beddedquartzites of white, grey, brown, or green colour alter-nating with brown-weathering carbonate quartzites,blue limestones of Kioto Limestone type and a fewshaly beds. The limestone beds may contain largeshells of Megalodon and Dicerocardium. Intraformationalbreccias and current-bedding are frequent in theseshallow-water beds, marking a general regression inthe Himalaya. Towards the top the sand content de-creases and the Quartzite Series passes into the KiotoLimestone.The age of the Quartzite Series is generally accepted

to be Upper Noric to Rhaetic.

2.13. The Kioto Limestone(HAYDEN, 1908)

From the Quartzite Series a 500-600 m thick carbo-nate sequence develops, forming conspicuous cliffs androck faces. The Kioto Limestone is a thick-bedded suc-cession of grey, blue, and black, partly nodular lime-stones, grey dolomites, subordinate marls and a fewarenaceous layers in the lower part. Many of the dolo-mites are the product of dolomitization. Oolithic, oncoi-dal layers, fossil debris, current bedding large scale rip-ples and intraformational breccias indicate deposition inshallow water. From their facies studies GAETANI et al.(1986) infer a "transgressive-regressive sequence start-ing with medium to high energy inner shelf environmentcharacterized by bars, channels and small patch reefs.Low to medium energy subtidal inner shelf conditionswith poor but differentiated fauna and extensive biotur-bation follow. In the middle part of the unit low energy,interior platform conditions are documented. The upperKioto Limestone is interpreted as medium energy innershelf with terrigenous supply possibly connected toshort term base level fluctuations" (p. 464-465).The fossils are mainly algae, benthic foraminifers,

corals, bryozoa, brachiopods, gastropods, bivalves, andcrinoids. Typical are shell beds of Megalodon, Dicerocar-dium, and Lithiotis. The age is accepted Rhaetic to EarlyDogger.

477


2.14. The Ferruginous OoliteThroughout the Tethys Himalaya a thin ochreous

weathering band follows the Kioto Limestone and un-derlies the dark Spiti Shales. This marker horizon ofUpper Dogger age was studied in much detail byJADOULet al. (1985) and GAETANIet al. (1986) in south-ern Zanskar:A) The lowest Iithozone (0.5-10 m) an 001 it hie

i r0 ns ton e rich in fossils follows on the KiotoLimestone after a gap, which was larger in the E.

B) Varicoloured shales with scattered belemnites,ammonites, and ferruginous ooids (2-20 m).

C) Cross-bedded bioclastic quartzarenites 20 m)D) Fossiliferous oolitic arenites (2-5 m)The Spiti Shales follow with sharp contact.The time gap between the Kioto Limestone and the

Ferruginous Ooolite (Early resp. Middle Callovian toLate Callovian) spans at least 10m. a. (JADOULet aI.,1985). During this time deposition continued in otherparts of the Tibetan Zone. In Nepal, for instance, theKioto Limestone grades into the Lumachelle Formation,which in turn is succeeded by a ferruginous impurelimestone bed of Callovian age (EGELERet aI., 1964;FUCHS,1967; BORDETet aI., 1971). In Kumaun the Lap-tal Series corresponds with the Lumachelle Formation,and in the Shalshal Cliff the beds between the KiotoLimestone and the Sulcacutus Beds (DIENER,1912,p. 101, fig. 9). In these regions there may be a slightgap at the base of the Callovian ferruginous bed, in thewestern Himalaya, however, its time span is obviouslylarger.

2.15. The Spiti Shales(STOLlCZKA, 1865)

The formation consists of soft, green-grey to black,silty shales with sporadic thin layers of dark impurelimestone or siltstone. Dark concretions are not rare.Ammonites and belemnites are frequently found butpoorly preserved. GAETANIet al. (1986) observed alayer of fine-grained sandstone and graded calciruditerich in belemnites and ammonite fragments at the baseof the formation. In the same position a belemnite bedis recorded from Spiti (FUCHS,1982a, p. 351). The SpitiShales are ca. 20 m thick in western Zanskar, ca.100 m in the lower Oma Chu, and attain 100 to 150 min the lower Niri Valley. Due to the soft rocks the SpitiShales are frequently covered by float and good expo-sures are rare.The formation was deposited in deeper water, (outer

shelf) under euxinic conditions as indicated by the darksediment colours.The age of the Spiti Shales is generally accepted as

Upper Oxfordian to Lower Neocomian.

2.16. The Giumal Sandstone(STOLlCZKA, 1865)

The Giumal Sandstone shows brown ferruginousweathering colours, by which the formation can beeasily traced on satellite imagery. In the region of theZanskar Valley the Giumal Sandstone consists in itslower part of a thick-bedded sandstone sequence withsubordinate pelites interbedded, and an upper part with

478

prevailing dark argillites. The lower part rich insandstone is approximately 200 m thick in the NamtseLa section, 120 m at Zangla; the upper more shaly por-tion is 80 m in the first, 180 m in the second area. Thesandstones and quartzitic sandstones are fine tomedium-grained and show grey-green colours. S-planes are often uneven and burrowed and the rocksdisintegrate to large irregular blocks. There are alsobeds of white, green, grey, and black fine-to medium-grained quartzite. The arenites are interbedded withblack shales and silty shales, which are often found asclay fragment breccias in the sandstone. In the OmaChu-Zangla area the uppermost sandstone bed fre-quently shows dark blackish colour. As I suspected acorrespondence with the phosphoritic beds at the top ofthe Giumal Sandstone in other parts of Ladakh de-scribed by FUCHS(1979), BAUDet al. (1982b, p.355)and GAETANIet al. (1986, p. 468), I gave a sample forchemical examination. Dr. P. KLEIN,Geol. B.-A., kindlyinformed me that there was a P20S content of only0.6 %, Mn 0.06 %, but Fe 23.8 %. Thus the dark sedi-ment colour is obviously caused by iron compounds.GAETANIet al. (1986) on the basis of detailed studies

subdivided the Giumal Sandstone into three parts: thelower one (160-200 m) consists of dark greysandstones and pelites, the latter becoming prominenttowards the E (Tantak). A forams find points to LateAptian, possibly Albian age. The middle part(110-130 m) is composed of dark grey shales and thin-bedded laminated sandstones. The upper portion(90-100 m) commences with very coarse-grainedcross-bedded quartzarenites, followed by pelites, vol-canic arenites and biocalciruditic layers with belem-nites. Then come black glauconitic sandstones severalm thick. As the arenaceous bodies are fining if tracedto the E, the middle and upper Giumal are difficult toseparate in the Zangla area.The terrigenous debris comes from the SW from a

continental source. It was deposited in deltaic systems,which pass laterally into offshore pelites towards theNE (BAUDet aI., 1984; GAETANIet aI., 1986; FUCHS,1986, p. 426). The basic volcanic influence recognizedby GAETANIet al. is a problem. Should we accept alocal source from basaltic intercalations in the Spiti-Shales recorded by KANWAR& BHANDARI(1979)? Was itbasaltic volcanism related to the initial rifting betweenIndia and Australia as envisaged by GAETANIet al.(1986, p. 469)? Or should we assume that the northernmargin of India was already in a distance from theIndus suture to be influenced by the volcanic arc (Dras)already active then?The age of the Giumal Sandstone is Upper Neoco-

mian to Late Cenomanian. The upper boundary has be-come younger by recent ammonite finds (GAETANIet aI.,1986, p. 468).

2.17. The Chikkim Limestoneand

Shillakong FormationThe dark coloured terrain built by the Giumal

Sandstone is overtowered by light-weathering carbo-nate formations of distinct pelagic character. They areeither grey or blue - the Chikkim Limestone named bySTOLlCZKA(1865) - or consist of a varicoloured alter-nation of limestone, marl, and pelites - a couches


rouges facies - termed Shillakong Formation by FUCHS(1982b; synonym Fatu La Formation). In westernZanskar the Chikkim Limestone is confined to thesouth-western portions of the Tibetan Zone. Towardsthe N it thins out from 50 m to a few m only. The Shil-lakong Formation, on the contrary, is missing in the SWand attains several hundred m thickness in the N. Thusin the N the multicoloured facies replaces the grey one.In the transitional zone the Chikkiim Limestone alwaysunderlies the Shillakong Formation. This facies changeis more abrupt in western Zanskar because the north-ern parts (N. Z. U.) border the southern parts of theTibetan Zone along a thrust of a few km displacement(FUCHS, 1982b). E of the Zanskar River this tectonicplane has died away and the northern and southernfacies belts are connected. It was my aim to study thefacies intertonguing and the way of mutual replacementof the Mid and Upper Cretaceous formations.The Chikkim Limestone is a well-bedded se-

quence of grey, rarely blue, partly nodular dense lime-stone with extensive bioturbation. The rocks are free ofterrigenous detritus and full of foraminifera, however ill-preserved. Shale partings are subordinate. The foramsdetermined by R. OSERHAUSER in my samplessuggested Cenomanian to Campanian age (FUCHS,1982b, p. 9). GAETANIet al. (1986, p. 469) were able todefine the age of the base as Early Turonian, the top asuppermost Santonian. From their description it is notevident, why these authors assume a hiatus betweenthe Chikkim Limestone and the Kangi La Formation.Contrary I found passage beds yielding a Campanianfauna (FUCHS, 1982b, p.9).The Chikkim Limestone was deposited in upper

bathyal pelagic environment poor in oxygen and withlow rate sedimentation (GAETANIet aI., 1986).The Shillakong Formation (FUCHS,1982b) con-

sists of an alternation of cream, red, green, grey, andblue limestones and red, purple, green slates andmarls. This series is banded in dm to decametricrhythms. Frequently the rocks show fine recrystalliza-tion, phyllitic alteration, and transversal cleavage.The abundant foraminifera are recognized by the un-

aided eye, but difficult to determine due to recrystalliza-tion. In the following I shall describe a series of strati-graphic sections in the region investigated. In southernZanskar the Shillakong Formation has its westernmostoutcrops in the lower Oma Chu, further W it is replacedby the Chikkim Limestone and Kangi La Flysch.Our westernmost section was measured along the

ascent from the 0 maC hu to the Ha lu maL a (trail toLingshet): The boundary between the GiumalSandstone and the succeeding pelagic limestones issharp, but tectonically disturbed. In the orographicallyleft slope a wedge of the carbonates is pushed into theupper portion of the Giumal Sandstone. KELEMEN&SONNENFELD(1983, p. 272) seem to interprete this situ-ation as facies intertonguing between the ShillakongFormation and Giumal Sandstone. But without doubtthis is a local tectonic reduplication.The uppermost bed of Giumal Sandstone is almost

black, fine- to medium grained sandstone with somecross bedding. In thin section it can be seen that thegroundmass as well as part of the quartz grains havebeen replaced by black to dark brown iron compounds(analyt. kindly by Dr. P. KLEIN, Geol. B.-A., Vienna).With sharp boundary well-bedded, blue-grey limestones

follow. Sample 85/38 immediately above the baseyielded (all determinations kindly by Dr. R.OSERHAUSER,Geol. B.-A., Vienna"): Strongly recrystal-lized forams, from their shape highly probableCe nom ani a n (to Lower Tu r0 n i an) .Sample 85/36 from the basal blue-grey limestones

yielded: Rotall{Jora and Diearinella of an associationsuggesting Uppe rmost Cenom an i an:

R. ex gr. eushmanniR. ex gr. deeekeiPraeglobotruneana ex gr. algeriana-imbrieata

Approximately 20 m above the base of the carbo-nates they become multicoloured. Sample 85/39 takenin these beds contains:

Globotruneang ex gr. sigali-sehneegansiAge: Turonian (or younger)

The basal grey-blue beds correspond in facies withthe Chikkim Limestone the overlying multicolouredlimestones are Shillakong facies. Both facies togetherare 50 -100 m thick. At the top the Shillakong Forma-tion is succeeded by dark grey to black marly and siltyslates, a ca. 1000 m thick series assigned to theLamayuru Formation by FUCHS(1982b). Sample 85/40from their lower part yielded: well-preserved Globotrun-canas.

G. areaG. ex gr. stuartiAge:U pp e r Ca mpan i a n (Maestrichtian can notbe excluded)

The next section was studied along the ascent toNamtse La from the S: The Giumal Sandstone is suc-ceeded with sharp boundary by blue-grey, thick beddedlimestone. Sample 85/32 from the base of the carbo-nates yielded: abundant small Thalmanninella, Praeglobo-truneana, and Globigerina proving Up per A Ib i a nage.This is the only sample free of recrystallization.8 m above the base the carbonates become multi-

coloured. The red and green marly limestones exhibitbioturbation. Sample 85/33 contains a poorly preservedfauna, which allows only the identification as UpperCretaceous.Sample 85/34 ca. 15 m above the base, rather

sheared, yielded Globotruneana cf. eoronata BOLLI. Thefauna suggests Upper Turonian to Coniacianage.In the Namtse La section the Chikkim facies is

8-12 m, the Shillakong facies about 40 m thick. Thecarbonates are overlain by a several hundred metersthick complex of black slates. A sample 85/35 from thelowest portion of these slates yielded small Globotrun-canas, G. ex gr. area, suggesting Up per Ca mpan i an.

Further E the next section was studied in the gorge Nof Z a ng Ia: the dark silty slates and siltstones of theupper Giumal Sandstone are followed with distinctboundary by thick-bedded, grey to dark blue limestoneswith black shale partings. Sample 85/26 taken from thelowest limestone bed yielded abundant, but iII-pre-served Rotaliporas and Praeglobotruncanas.

*) Dr. R. OSERHAUSER notes that most of the foraminifera tests(all of them planktonic forms of Middle to Upper Cretaceousage) are strongly recrystallized. Therefore the examinationsoften had to be based on outer shape and the size, naturallylimiting the possibilities of determination.

479


R. ex gr. appenmmca (very frequent)R. cf. cushmanni (very frequent)R. reicheli (rare)Pr. stephani (frequent)Age: middle part of Cenomanian

Sample 85/27 ca. 12 m above the base contains ill-preserved planktonic forams. As Praeglobotruncanasare associated with the first double-carinated forms, thesample is from the Ce no ma n i a n - Tu ro n i an bound-ary. About 40 m above the base the varicoloured carbo-nates (85/28) yielded: poorly preserved one keeled andflat double-keeled tests, such as Globotruncana coronata.Age: Upper Middle to Upper Turonian (LowerConiacian can not be excluded).Sample 85/29 is derived from the core of the

syncline: In the schistose rock flat double-keeled formsare just recognizable. The age is probably Up perTu ron i an - Con iacian.Sample 85/30 was taken from the lowest multi-

coloured beds just above the Chikkim facies of thenorthern limb of the syncline. It yielded undeterminableGlobotruncanids.From the upper Chirche Valley NE of Zangla

BAUDet aL (1982b, p. 535) describe a section acrossthe Cretaceous rocks of a syncline NE of the one de-scribed above:The uppermost bed of the Giumal Sandstone - a

sandstone with black phosphate nodules - yielded anA Ib i a n microfauna. Varicoloured marly limestonesshowing bioturbation follow (Shillakong Formation).From the lowest bed BAUDet aL recovered an Up perA Ibi a n microfauna. Higher up Ce nom ani an faunaswere found in the Shillakong Formation. The changefrom multicoloured pelagic carbonates to black shalefacies occurred in the Up per Ce nom ani an. Thedark series yielded Up per Ce nom ani an, Up perTuronian and Turonian-Coniacian faunas. Thedark shales pass into monotonous marly limestone ofbrownish colour tentatively related to the Kangi LaFlysch (FUCHS,1979).The SE continuation of the Cretaceous syncline de-

scribed above was studied near the village Shad e.There the Giumal Sandstone, composed mainly of siltyshales, is overlain by blue-grey marly limestone suc-ceeded by black marly slates. Samples 85/41 and 85/42are derived from the dark basal limestones: The first -lower in the sequence - yielded ill-preserved Globo-truncanas.

Rotalipora cf.reicheliRotalipora ex gr. cushmanniPraeglobotruncana stephaniAge: Probably lower Middle Cenomanian85/42 contains poorly-preserved partly double-keeled

Globotruncanas leaving open Up per Tu ro ni a n toCa mpan ia n age. In the float of the eastern slope ofthe hill N of Shade I found sporadic rock fragments ofred colour, but the Shillakong facies seems to be verysubordinate or missing in the Shade area. There theChikkim facies appears to pass directly into the blackshale (Lamayuru) facies. The multicoloured (Shillakong)facies is only locally interbedded.From the above descriptions it is evident, that the

Shillakong Formation from place to place is of differentage.The Shillakong facies seems to start first in the

Chirche (BAUDet aL, 1982b) and Namtse La areas - in

480

the Albian. Cenomanian faunas are reported by BAUDetaL (1982b), who found the change from couchesrouges to black shale facies already in the UpperCenomanian (Chirche Valley). Very likely these Turo-nian black shales join up with the black slates replacingpart of the Turonian pelagic limestones and marls in theKhurnak area (FUCHS,1984a, 1986). There Turonian aswell as Santonian to Maestrichtian Shillakong Forma-tion are documented. GAETANIet aL (1986) find the for-mation bracketed between Turonian and Early Campa-nian in the region W of the Zanskar River. In the north-ern parts of Zanskar from the Khurnak area mentionedabove towards the W (Fatu La) the Shillakong Forma-tion reaches up into the Upper Campanian (BASSOULLETet aL, 19780; FUCHS,1986) and attains its greatestthickness.As to the environment it is characteristic that the Shil-

lakong Formation and the Chikkim Limestone are freeof terrigenous debris, consisting mainly of plankticforaminiferal remains and pelitic-calcareous muds. Thebright colours of the Shillakong formation indicate bet-ter oxygenation than the Chikkim Limestone (GAETANIet aL, 1986, p. 470). The first appears to be depositedon sills, pelagic plateaus or seamounts (FUCHS,1982b;GAETANIet aL, 1983), whereas, the latter points todeeper less aerated conditions. Both formations aresucceeded by thick clastic formations. The Campanianto Lower Maestrichtian Kangi La Flysch follows on theChikkim Limestone. Its areno-argillaceous material wasderived from the S from the Indian Craton. N of this ter-rigenous basin the pelagic sedimentation persisted on aswell, unaffected by detrital influx. The pelagic faciesinterfingers with euxinic basin facies (Lamayuru) bor-dering mainly in the N. With the Maestrichtian the darksilty-pelitic series transgresses the subsiding swell, put-ting an end to the Shillakong facies.

2.18. The Upper Partsof the

Lamayuru Formation

In the last chapter it was described that in all sec-tions the multicoloured Shillakong facies is overlain byblack silty argillites. FUCHS(1982b) correlated thesebeds to the Lamayuru Formation in the N and explainedit as an overlap of the basin facies due to subsidenceof the pelagic ridge. KELEMEN& SONNENFELD(1983) andGAETANIet aL (1983, 1986) connected these series withthe Kangi La Flysch of SW-Zanskar. Though both com-plexes are flyschoid I felt it necessary to distinguishthem for following reasons:o Lit hol 0gy: At the top of the Shillakong Formation

the red and green colours turn into dark grey toblack, but the slates and marls still abound inforaminifers, easily recognizable by the naked eye.Though the formation becomes more silty, it can notcompare with the arenaceous Kangi La Flysch. Theprevailing rocks are dark grey to black, silty slatesbleaching on weathering. The lithology is so similarto the Lamayuru Formation that it is almost impossi-ble to discern the overthrust Lamayuru rocks of theSpongtang Outlier form the underlying series inquestion, where the separating Tertiary formations(Lingshet Limestone, Kong Slates) are cut out bytectonics.


Contrary the Kangi La Flysch shows ochreousweathering and grey, dark grey and green sedimentcolours. The rocks are siltstones, silty marls, slates,and thin-bedded sandstones. In the upper portionsof the formation sandstones become prominent.

o Age: By increase of silt and sand the ChikkimLimestone (Upper Santonian) passes into the KangiLa Flysch. The passage beds yielded Campanianfaunas (FUCHS,1982b; GAETANIet aI., 1986). Thetop of the Kangi La Flysch is Maestrichtian (GAETANIet aI., 1986) and is succeeded by Upper Maestrich-tian - Paleocene shallow-water carbonates (Span-both Formation).The Shillakong Formation spans a wide range oftime - from Upper Albian to Upper Campanian. It isinterfingering with the Lamayuru basin facies in theN. In the SE the basin facies starts to overlap thepelagic carbonates in the Upper Cenomanian (BAUDet aI., 1982b) respectively Upper Turonian (sample85/40), finally putting an end to this facies after theUpper Campanian. The parautochthonous LamayuruFormation around the Spongtang Klippe yielded onlyMaestrichtian foraminifers (FUCHS, 1982b). Theseblack pelites are succeeded, possibly after a hiatusby the Paleocene Lingshet Limestone. So the blackslates overlying the Shillakong Formation are UpperCenomanian - Maestrichtian, respectively onlyMaestrichtian, whereas the Kangi La Flysch is Cam-panian - Lower Maestrichtian.

. For the above reasons I prefer to discern betweenKangi La Flysch and the Cretaceous portions of theLamayuru Formation. The difference to the views ofKELEMEN& SONNENFELD(1983) and GAETANIet al.(1983, 1986), however, is not so great. There are trans-itions between these formations in the Kong-Wakhaarea of western Zanskar (FUCHS,1982b) and I do notdoubt that they were originally connected. The Kangi LaFlysch derived the terrigenous material from the Sandhas the character of distal flysch deposited in outershelf to bathyal environment (GAETANIet aI., 1983,1986; BROOKFIELD& ANDREWS-SPEED,1984). TheLamayuru Formation indicates turbidite deposition on abasin plain or possibly the outer part of a deep-sea fan(BROOKFIELD& ANDREWS-SPEED,1984, p. 260). I inferthat the Kangi La facies was closer to the cratonicsource. Its shallowing trend, shown by increase in grainsize, led to filling up of a basinal depression in theZanskar Shelf. The ridge with pelagic carbonatesedimentation N of the mentioned depression was fi-nally transgressed by basin facies after the Campanian.In Ma

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The Geology of Southern Zanskar Fuchs - 1987