56
2 nd Th e Int’l Symposium of International Geoscience Programme IGCP Project 608 Tectono-magmatic Development of Accreted West Burma Block from Naing Maw Than (MGSS) Gondwana Land 6 t h Sept, 2014, Wasewda 1 Photo courtesy by Dr. Win Swe (2012)

Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Embed Size (px)

Citation preview

Page 1: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

2ndThe Int’l Symposium of International Geoscience Programme IGCP Project 608

Tectono-magmatic Development of Accreted West Burma Blockfrom

Naing Maw Than (MGSS)

Gondwana Land6th Sept, 2014, Wasewda

1Photo courtesy by Dr. Win Swe (2012)

Page 2: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

The Second International Symposium ofInternational Geoscience Programme (IGCP) Project 608"Cretaceous Ecosystems and Their Responses to

Western Pacific"Paleoenvironmental Changes in Asia and the

I_UG_S

_ ...._..,._

EDU-"

·"

-.

2

Page 3: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

± Naing Maw Than, he received B.Sc. (Hons), M.Sc.Univ. of Mandalay and Dip. in Computer Science ofand M.Sc. (Petroleum Geoscience), Univ. of Brunei,

(Geology) fromI.C.S.T (Yangon)life member of

MGS (Myanmar Geosciences Society), AAPG and executive member ofMGSS (Myanmar Geologists Society, Singapore).He presently works as I/M manager Cum

basingeologist in SK E&C

(Singapore) and main interests in study and reservoircharacterization.

Page 4: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

_,.,I

Eastelock

Fig.1 ' I

Sunde Prati orSundaland' Block

/

Bay ofBengal

lndanOoean

4

Page 5: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

INTRODUCTION Two Hypothesis

It seems probable that the WMB and the Sibumasu were formerly independent blocks or slivers which rift at different times off a supercontinent known as the Gondwanaland in the southern hemisphere (Ridd, 1971, Stauffer, 1974), and drifted northward across different generations of Tethys Oceans, and collided and amalgamated with Asia, and also with each other (Metcalfe, 1997).

The present available data supported the above tectonic scenariofor the Sibumasu Block, more convincingly than for the earlyhistory of the WMB which needs more research work to verify.

5

Page 6: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

6

Fore –Arc Sliver Model (Mac Caffrey,2009)

Page 7: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

The Sibumasu Block probably rift off the NW Australia which was attached to therigid Antarctica to the south, both forming parts of the Gondwanasupercontinent until Carboniferous, and drifted northward in late Early Permian.

It collided and sutured in Late Triassic with the Indochina Block (IndosinianOrogeny), also of the Gondwana origin, to form the Sunda Block or Plate,covering much of the mainland of Southeast Asia and its offshore continentalshelves and also the southern margin of Asia (Figure 2 & 3).

7Hall et al. 2010 IPA

Fig.2

Page 8: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Sibumasu

Fig.3

) Collision

of Subumasu

Block

with

Indochina Block

r,

- Indochina

Song Gp

Hua/ Hin Lat Fms

- Fig. Cartoon sections across

Indochina

I Sibumasu

or

Indochina block in the Late..,I_

Sukholhai Arr; ..._

Accretionary

& granite

---• Oceanic crust

.. plate-tectonic setting. NUS: Nnn•-

8

Sibumasu

PALAEOTETHYS CLOSED BACK-ARC

Earliest Triassic ~--'--1 BASIN

Mae Slllfang Fm

Fanr; Chell

~Gp

MESOTETHYS

!Late Triassic!INTHANON ZONE Nam Pa/Gp

Nam Phong&

MESOTETHYS

Nonhern and NE Thailand to show the narrowing of the Palaeotethys ocean in the earliest Triassic and the final collision of the Sibumasu block with the Sukhothai Arc/

'----' Shan-Thai Terrane Terrane ._ ..,! Indochina Terrane Triassic (modified from

Sonc &

Metcalfe 2008}. Triassic lirhostratigraphic units have beenAcid volcanic rocks added to show their interpretedcomplex (S & I types) Utturndit Suture.

Page 9: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

The south Asian margin remained passive until Jurassic when itbecame an active margin with repeated magmatic andmetamorphic episodes, the latest thermal event occurring in lateMiocene.

WMB extending into West Sumatran block carrying an intra-oceanic magmatic island arc with continental basement alsofollowed suit from the other part from the northern margin ofAustralia probably in Late Triassic to Early Jurassic, and frontalmagmatic arc collided with the Sunda Block (Sibumasu part) inMid-Cretaceous,

while much farther south of their present position (Mitchell et al.,2007), leading to the formation of high-grade metamorphicMogok Belt along the collision zone and generating both I-typeand S-type granites in the belt. Subduction shifted to the westmargin of the WMB .

9

Page 10: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.4)

Myanmar

at the

junction

of four

tectonic

plates (After Win Swe. 2012)EHS

1. Eurasian Plate2. Indian Plate3. SE Asia/Sunda Plate4. Burma Plate

Major Structures in the region

1. MBT= Main boundary Thrust2. EHS= East Himalayan Syntaxis3. Sunda Mega thrust4. Sagaing Fault5. Andaman Spreading

(After Win Swe 2012)

10

Page 11: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

WEST MYANMAR BLOCK OR BURMA PLATE Composed of CMB, WR and RCB

CMB is probably a continental fragment overlain by Triassic –Recent clastic strataintruded by a volcano-plutonic arc (Mid-K-R) along its medial axis, forming an intra-oceanic magmatic island arc.Collided with Sibumasu block in mid-K creating high-to medium-grade metamorphicbelt and emplacement of both I-type & S-type granitoids along the suture zone,Mogok Belt.

Further subducted by the oceanic lithosphere from the west; Up K- Eocene., flysch ofaccretionary wedge (WR) and coeval sequence of Western Outcrops depositedrespectively in a trench and fore arc trough of the magmatic arc along the medial axisof CMB.

In Oligocene the accretionary wedge was uplifted in the W, dextral shear basins andSagaing Fault were formed in the E due to hyper-oblique subduction by theIndian/Australian Plate and subsequent indentation in Himalayan Arc followingcollision in the Himalayan Arc.

Dextral slip SF transects mostly along the old suture zone, and Andaman Basinopened in Miocene, offsetting Burma Plate northward for ~333 km and pushing WSumatra farther southwards 11

Page 12: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.5) FOUR MAJOR PHYSIO-TECTONIC BELTS OF MYANMAR

1. Eastern HighlandsProvince(EHP),Central Myanmar Belt (CMB)Western Ranges (WR),Rakhine Coastal Belt (RCB).

2.3.4.

WEST MYANMAR BLOCK ORBURMA PLATE Composed ofCMB (Triassic-Q) Wt.Metamorphic Basement ,WR (Up K- Plio)RCB (Eocene-Plio) andCVL Central Volcanic Line

12

Page 13: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Three Continental Blocks : East Malaya_Sibumasu_West Sumatara (Barber & Crow, 2009)

Southeast Asia is made up of a series of continental blockswhich separated from northern Gondwana during the LatePaleozoic and Mesozoic and were subsequently accreted to thesouthern margin of Asia with the subduction of the interveningoceanic crust.

From east to west the Malay peninsula and Sumatra arecomposed of three continental blocks: East Malaya, Sibumasuand West Sumatra (Barber and Crow , 2009).

13

Page 14: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

A Hypothesis of West Sumatara and West Burma Detachement outbord of Subamu in TR

Hutchison (1994) and Barber et al.(2003) proposed a hypothesis,during the Triassic an elongated slice, including West Sumatra andWest Burma, became detached from Cathaysia (Indochina) along amajor transcurrent fault and was translated along the westernmargin ofterrane.

SE Asia to its present position outboard of the Sibumasu

14

Page 15: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.6) Continental tectonic blocks in Southeast Asia (after Metcalfe 2005).

The contact between theSibumasu block and theWest Sumatra block ismarked by the MedialSumatra Tectonic Zone(MSTZ), a distance of 1760km and interpreted as amajor transcurrent fault.

Barber and Crow (2005)correlated the MSTZ withthe Mogok Belt ofMyanmar and the WestBurma block is theextension of the WestSumatra block, from whichit was separated by theformation of the AndamanSea in the Miocene(Curray, 2005).

15

Page 16: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

,94°EFig

~ -\

I

I

C

- ,,,. ,-,

' \

I

PLATEAU

I

I '

,_-' THAILII

' ' '' '-

16°

0

Shan Thai(Sibumasu) BlockD

290'' ' Late Cretaceous

Granites','

-Mogok Meta•morphic Belt = MSTZ

'

--

HINA

West Burma Block= West Sumatra Block Jurassic to Early K and were

24 Mawgyi Nappe= Woyla Nappe

Ophiolites

'

-

Mount Victoria metamorphics

-Cenozoic AccretionaComplexes

'} Deformation Front

AND

1 i

Strike-Slip Fault

QuaternaryVolcanoes

16°

16

Metcalfe (1996, 2005) suggested that the Sikuleh microcontinental terrane, incorporated in the Woyla terranes and the West Burma block, separated in the Late

accreted in the mid K.

The Woyla nappe is interpreted as an intraoceanic arc thrust over the West

rySumatra block and the WoylaArc was certainly accreted toSE Asia as part of the Woylanappe in the mid K.(Barber 2000; Barber & Crow2008).

.7

Page 17: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.8) Outline Map of Mawgyi Nappe in Western SE Asia (After Mitchell, 1993)

East-ward vergingMawgyi nappe of maficarc rocks and ophiolite inMyanmar andequivalents in Sumatra,Borneo and Tibet in Mid-K.

Myanmar west ofSagaing Fault restored toMid-K position.(After A. Mitchell, 1993)

17

Page 18: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.9)

Latest

Arrival

of Indian

Platform

to Eurasia at Eocene (After Win Swe. 2012)

The latest arrival of a majorblock of Gondwana origin inour part of Asia is the Indianplatform or subcontinentwhich left the parentGondwanaland in EarlyCretaceous, collided andsutured in Eocene with theEurasian Plate,an assembly of suturedblocks, leading to theformation of the greatHimalayan Mountain Rangeand the high TibetanPlateau.

18

GIAC Project (1999-2002)

Page 19: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.10)

Myanmar

at the

junction

of four

tectonic plates (After Win Swe.

2012)

1.2.3.4.

Sunda PlateBurma PlateIndia PlateEurasian Plate

Major Structures in the region

1. MBT= Main boundary2. EHS= East HimalayanSyntaxis3. Sunda Megathrust4.Sagaing Fault5. Andaman Spreading

Thrust

(After Win Swe 2012)

19

Page 20: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.11)

Present

Day

Tectonic

Setting

of Myanmar

(Win

Swe,

2012)

20

Page 21: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Present Day Tectonic Setting of Myanmar (Win Swe, 2012)

During northward indentation of India into Asia the region eastand southeast of Tibet underwent large scale right-lateral shearand clockwise rotation, the right-lateral Sagaing fault in Burmawhich marks the eastern margin of the NNE moving Indian plateduring the Neogene.

The consequences of this collision (Himalayan Orogeny) andcontinuing convergence between the two blocks are, amongothers, propagation of major lateral shears, in part probably byreactivating the pre-existing structures, to the east and southeast,translating continental blocks out of the collision zone androtation of the Sunda block or plate clockwise (Tapponner et al.,1986,2008), the processes commonly known as "Extrusion orEscape Tectonism”. (After Win Swe, 2012)

21

Page 22: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

g.12) CoIr)• llision in the Himalayan Arc (Tapponier et al, 2008) 105'

110 •

TAR J .UNOIITN

8 AST V

CHINA

oRoo•

35'

22

Fi

Page 23: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Regional DEM of Asia with outlines of key basins,Escape Tectonismand structural features

Molnar and Tapponnier model 23

Page 24: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

CVL (Central Volcanic Line) in Myanmac / Tettono Magmatic Development

Igneous rocks ranging in age from Lower Jurassic to Pleistocene or earlyRecent occur sporadically in a1500 km long ‘volcanic arc’ throughout the Central Lowlands (Chhibber1934). The arc coincides with an axis within the Central Lowlandssedimentary basin (Central Burma Basin), dividing it into Western andEastern Troughs that represents arc volcanism above an east-dippingsubduction zone . The Central Volcanic Line (CVL) arc is terminated by Southat Andaman sea spreading center which has been active since Mid-Miocene(Curray, 1979).

Mitchell (1981), Stephenson and Marshall (1984) stated that prior to theinitiation of the Andaman Sea spreading centers the volcanic arc wascontinuous southwards with the Sumatra and Sunda arcs of Indonesia(Hutchison 1982), in which many high-K calc-alkaline volcanic centers havegeochemical and mineralogical similarities to the Burma volcanics (Whitford1975; Whitford & Nicholls 1976; Leo et al. 1980).This is particularly true in northern Sumatra where fault controlled Miocene toRecent volcanoes, with remarkable similarity to those of comparable age inBurma, are developed on the southwestern continental margin of the

Sundaland Craton (Rock & Syah 1983) (See in Stephenson and Marshall, 1984).24

Page 25: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.13) Geological

Map

of Myanmar

(MGS,

2014)

Mitchell et al. (2012)speculated that, inCretaceous the Wuntho–Popa arc (United Nations1978c) was much furthersouth, within the westernpart of the presentAndaman Sea andpossibly Sumatra–Wuntho–Popa–Mokpalin arccontinued northwardsthrough diorite andgranodiorite intrusionswithin the TagaungMyitkyina Belt (TMB) ofBurma.

Kaw Lin-Wuntho

Popa

25

Mokpalin

Page 26: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.14)Generalized Geological cross-section of Myanmar

,along Lat. 21˚

N

26

Southern Chin Hills MinbuBasin Chauk ML Popa Meiktila-Thazi PindayaPlain Range

GENERALLIZED GEOLOGICAL CROSS-SECTION MYANMAR,APPROXIMATELY ALONG LATITUDE 2 r NORTH

(Vertical scale greatly exaggerated)

I - Chaung Magyi Group; 2 - Lower Paleozoic units; 3 - Lower Carboniferous units;

4 - Plateau Limestone; 5 - Jurassic units; 6 - Mesozoic granitoids; 7 - Upper Cretaceous Paleocene ultrabasic rocks;

8 - Mesozoic-Eocene flysch; 9 - Eocene molasse; 10 - Pegu Group; l I - Irrawaddy sandsones; 12 - Upper Cenozoic volcanics; 13- Alluvium

Dr. U Thein, 2000

Page 27: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

• 6 L9',t·C.,.- .. -- (t •

c:, '-"-• Fig.15

45

622•

7

8

THAILAND

....

1• tt,•

2

3

N

Lahar Deposits

Basalt, Basaltic Andesite & Pyroclastic ofComposite ConesBasalt & Lava Plateau

Dacite and/or Rhyolitic Pumice Flow

Rhyodacite ? Lava Domes

Andesitic Flows

Silicified/ Argilized Lava

Kyoukpodoung

~--··- ·-··--·--·- ...

N

Younger Volcanics

Older Volcanics

·

LJ lffowodd1on HO•tntntJ -Plioctnt

E!!J Peguon Mdrl're' -nts

·Miocene

• PlugO Cr(lflf

+ * Ao!;clone ond

>yn<I"'<Torrood

~Flow

·

f

Schematic section Vertical exoggeratioo i 2

27

Fig.1 A) 1.Narcodam, 2. Myaung Mya; 2, Narcodam Island, 3.Barren Island, 4. Mt.Loime & Jade Mine area, 5. Taungthonlon Volcano, 6. Lower Chindwin Cones, 7.Sone Taung Flows, 8.Mt.Popa, 9. Pegu Yoma Hills, 10. Tigyaing Flow, 11. Kabaw Flows, 12. Yezin,13.Thaton, 14. Medaw Island, Tectonic Features of Andman Sea from Curray et al. (1979)

Page 28: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.16) Location ofet. al. 2004)

Samples on the Mt. Popa

Area Geological Map (After Stephenson et. al. 1984) (Mauay

1: sedimentary substratum of the volcano(Miocene to Lower Pleistocene);2: dacitic and/or rhyolitic pumice flows;3: andesitic flows;4: dacitic domes and flows;5: basaltic and basaltic andesitic flows;6: basaltic and andesitic basaltic pyroclasticdeposits from Mt. Popa cone;7: Popa (Taunggala) neck.

28Older Volcanics

Irrawaddy Fm.Pegu Group

Younger Volcanics

Page 29: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

29

Fig.17) Satellite Image of Mt.Popa and Taungni Area

Mt.Popa

Dangyin

Taungni

Mongan

Page 30: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Microscopic Study of the Popa_Taungni Area

a

Fig. 18A) Mongan Andesite : the penetrated

twin plagioclase altered to sericitesubparallel with mcrophenocrysts of plagioclase (a) showing flow

directionFig. 18B) A phenocryst of hornblende (b) was replaced

and etched

around

itsboundarywit

hPerlitic

crck

(c) as

contraction

of cooling

stage

Fig. 19A) Orthopyroxene (d) was replaced by clinopyroxeneform the rim, while the inner core is fresh indicates the slow

(e) and magnetite torate of crystallizationFig .19B) Zoning and Twinning in auguite phenocryst with ophitic

texture andmicro phenocrysts of plagioclase in fine-grained groundmass

30

d

e

c

b

Page 31: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

XRF

data of

Taungni Volcanic

Rocks

Plot

in Alkali

Vs.Silica

Diagrams

2

Fig.20 A & B ) XRF data of the Taungni volcanic

rocks

are plotted

in the alkali Vs. silicadiagram and K2O Vs. Silica diagrams indicate that most of samples are in the

alkaline andhigh K-calc alkaline fields.

Although such high - K Calc alkaline suite are known from island arcs, they are moreprevalent on continental margin where they are often associated with extremely K rich shoshonitic rocks.

31

K2 O

(W

t %

)

Alkaline

Sub Alkaline

4

Shoshonitic

3

High –K Alkaline

1

Calc Alkaline

Low_K

040 45 50 55 60 65 70

Si O2 (Wt %)

Page 32: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

32

Volcanic

Rocks

Plot

for Mt.Popa

and other

environs

Singu,

Monywa,

Narcodam,

Barren Islands

Fig.21A) Plot of the studied

lavas in the classification diagrams Na2O + K2Ovs. SiO2 [Le Bas et

al., 1986] and K2O-SiO2 [Peccerillo and Taylor, 1976].

Fig. 21B )Filled circles: Mt. Popa basalts; empty circles: Mt.Popa basaltic andesites; empty

crosses: Mt. Popa andesites; empty diamonds: Mt. Popa dacites;

empty squares: Singu lavas; empty triangles: Monywa lavas;

empty inverted triangles: Tengchong lavas.(Maury et. al. 2004)

Page 33: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

33

Genesis of Magma

Although such high - K Calc alkaline suite are known from islandarcs, they are more prevalent on continental margin where they areoften associated with extremely K rich shoshonitic rocks. A generalincrease in K2 O in lavas (for any given Si O2 contents) is usual withincreasing depth of magma generation along a subduction zone.

Most XRF data of the volcanic rocks in the Taungni area are plottedin the field of Potassium-rich Calc-alkaline suite which is attributedto the waning stage of orogeny as the obliquely eastwardsubduction of the Indian Plate beneath the Eurasian Plate that gaveway to strike-slip movement associated with the Andaman Seaspreading-centre.

Page 34: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

34

Genesis of Magma

Within this tectonic model, the generation of potassic magma involved the partial

melting of phlogopite-bearing garnet peridotite at relatively deep levels in the

upper mantle (120 Km+), below the amphibole stability (Gupta & Yagi, 1980)

and the more siliceous lavas may have been derived by fractional crystallization

of such magmas at crustal levels (See in Stephenson and Marshall, 1984).

Stephenson & Marshall (1984) cited the observed spatial

continental margin is that in which sub-solidous aqueous

the dehydration of subducted oceanic crust, rise through

enriched mantle, scavenging incompatible elements.

variation beneath

solutions, released by

the overlying, possibly

The overall amount of enrichment would be in proportionate to the thickness of

overlying mantle and steepening of the subduction zone.

Page 35: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

35

Genesis of Magma

The volume relationship tend to support a fractional crystallization for the origin of more

silicic rocks. The basalt and basaltic andesite of the Mt.Popa (Younger Volcanics) are

volumetrically far more abundant than andesite and silicified tuff (Older Volcanics) of the

Taungni area.The overall trend towards more primitive composition with volcanic time which is contrary

to other areas of calc-alkaline volcanicity. During the earlier stage, the

magma may have risen to the surface fairly, slowly allowing time for

fractional crystallization of plagioclase and Mg-bearing mafic phase to modify

the magma to older volcanic composition.Later activity, which followed a period of deformation, consisted almost entirely of

relatively undifferentiated Basalts and basaltic Andesite (Younger Volcanics).

These magma exploited newer-formed weakness and risen to the surface

rapidly, not allowing time for fractonation.

Page 36: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

36

Fig.22) The three dimensional geometry of the Burma Wadati Benioff Zone (WBZ) , James. F. Ni. et al.(1989)

It was based upon the 184 hypocenters fromInternational Seismological Center (ICS).

The dip of the

inclined

Burma WBZ(subduction

IndianPlate) varies from about

the north near the east50 Southeast

inHimalayan syntaxis

to about 30

Northeast inthe bay of Bangal

area .the

extrapolated

trend surface

160

Kmcontour would pass through the volcanic arc inmap view.

Mt.Popa

Page 37: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

The Main Large –Scale Tectonic features of The Myanmar_Thailand Area Cross~18° N. (Searle & Morley,2011)

Fig. 23)

Cross-section across southern Myanmar and northern Thailand illustrating some of themain large-scale tectonic features of the area. The surface geology used is taken

from ~18° N.(Searle & Morley, 2011). CVL was probably generated at the depth 180 Km..

37

Page 38: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.24)

The Characteristics of the Burma Seismic Zone (Stroke et. al., 2008)

Current findings of

Stroke (2008) and

Searle & Morley

(2011) also

supported the

magma generation

depth range

(160-

180)

Km.

west-vergent fold-

FB

38

CMBFault

Himalaya Jade Mine Katha-

Belt GangawRange

Shilong PlateauPop-up Structure

Mogok Belt

Indo-Burma Ranges

Mt.Popa

thrust belt

Sagaing DI

Shan-Thai Block

Page 39: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Relation of Sedimentation, Volcanism and Tectonic Occurrences in Popa-Taungni Area

Pivnik et.al (1998) proposed :(1) Miocene extensional deformation of the20°N uplift and in the southeastern part of the Salin subbasin and the formation of grabens;(2) late Miocene uplift of the eastern side of the basin due to emplacement of the Mount Popa volcanics along basement-involved faults;(3) late Miocene–Pleistocene motion of the basin-center thrust sheets and formation ofthe Salin synclinorium (including uplift of the western outcrops); and(4) Pleistocene inversion of previously existing normal faults to form the southeastern uplifts and the 20°N uplift.

39

Page 40: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Relation of Sedimentation, Volcanism and Tectonic Occurrences in Taungni Area

From the Polyphase deformation of the Salin basin by Pivnik et.al (1998), firstly the Taungni area(the Older Volcanics) related with late Miocene uplift of the eastern side of the basin alongbasement-involved faults , secondly Pleistocene inversion of previously existing normal faults to form the southeastern uplifts and the 20°N uplift that related to Popa area (The Younger Volcanics).It could be extracted that the intraformational Irrawaddy unconformity in Gwegyo area alsosuggesting that transpression related uplift occurred after or during deposition of the upperIrrawaddy Formation, (Pleistocene), coeval with the basin-center thrust sheets.

40

Fig. 16) The Older Volcanics of Taungni Silicified Tuff and Dangyin Trachy Andesite intefingerring and overlying withIrrawaddy Fm. (Stephenson et. al. 1983).

Fig. 17) Schematic inversion of Gwegyo Thrust, unconformbly overlying Irrawaddy Fm. date the Pliocene_Pleistocene time.

Irrawaddy Fm.Altered Argillized & Silicified Rocks

Kyauktaga Volcanics

Trachyandesites

Irrawaddy Fm.

Page 41: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Depth-to-magnetic basement map of Central Myanmar Popa-Taungni area (Pivnik & et. al. 1998)

This inversion occurred in the Popa region as

resultant of Subduction co-exist with lateral strike-

slip fault forming the compressional and

transpressional deformation in Central Myanmar

basins.

The Mount Popa volcanics are interpreted to coincide

with basement fractures or faults; thus uplift in the

region also may be related to basement-involved41

Fig.15) Tomographic Patterns indicate E-NE trending uplifts possibly related to the Mount Popa volcanic trend, whichalso may be related to the normal faults (Pivnik, & et. al1998).

Regional uplift related to intrusion and extrusion of the Mount Popa volcanics appears to have tilted the footwall of the Gwegyo thrust

Fig. 16) Schematic inversion of Gwegyo Thrust, unconformbly overlying Irrawaddy Fm. date the Pliocene_Pleistocene time.

Mt.Popa

Page 42: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

42

Genesis of Magma, Depth of Magma Generation

Morrison (1980) suggested that steepening of subduction plate can occur beneath a

thickening crust towards the end of an orogenic phase and prior to a flip (overturning) of

the zone or a change to strike-slip movement such as has recently occurred in Myanmar.It can be concluded that the magma generation of the Popa-Taungni area indicate a depth

range of (120-160 ) Km at relatively deeper part of the upper mantle related with

compressional and/or transpressional movement.Current findings of Stroke (2008) and Searle & Morley (2011) also supported the magma

generation depth range (160-180) Km.

Maury & et. al (2004) proposed The dehydration of this slab led to metasomatism and

subsequent melting of the Central Myanmar mantle wedge, and finally to the emplacement

of calc-alkaline and shoshonitic magmas in those volcanoes.These evidences provide a most useful local tectono-magmatic analogy and supportive for

West Burma block is the extension of the West Sumatra block.

Page 43: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Conclusion

1) Continental blocks of SE Asia separated from northern Gondwanaduring the Late PZ and MZ and were subsequently accreted to thesouthern margin of Asia with the subduction of the interveningoceanic crust.

2) From east to west the Malay peninsula and Sumatra are composed ofthree continental blocks: East Malaya, Sibumasu and West Sumatra.

3) Myanmar exits at the junction of four plates : Sunda PlateBurma Plate, India Plate and Eurasian Plate.

4) Myanmar is composed of two paleo-micro-continental blocks: Eastand West Blocks, both believed to be of Gowndana origin in MidCretaceous).

5) West Burma Block (Burma Plate) can be correlated withSumatra by Magamatism and intraoceanic arc thrust.

West

6) For correlation of Woyla Nappe and Mawgyi Nappe is needed moreresearch works to do.

Page 44: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Magmatic Activity Vs. Tectonic Stress, Time of Volcanism

Times of volcanism were drawn by the reviewing on Polyphase deformation of the Salin

basin (Pivnik et.al,1998) and stratigraphic evidences, firstly the Taungni area (The Older

Volcanic) related with late Miocene uplift of the eastern side of the Salin basin along

basement-involved faults.

Secondly, late Miocene–Pleistocene motion of the basin-center thrust sheets and formation

of the Salin synclinorium that probably related to Popa area (The Younger Volcanic)

supported by the age determination on samples of Mt. Popa’s area which indicate the early

Pleistocene age (0.80 to 0.96 m.a.) (Maury et. al. 2004).

44

Acknowledgement

• I tender my sincere thanks to Dr. Win Swe (Past President ofMGS

(Myanmar

Geoscience

Society)

who

drawn

acomprehensive

picture

of Myanmar1970.

Tectonic

Map

and

firstlynamed the Sagaing

Fault in

• Extended warmly

thanks

to those

referred chance

in context

andorganize

rsof IBCP60

8who

gave

a to meet

shadyWaseda

Campus.

([email protected])

Page 45: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

REFERENCES :

1)Barber A. J. 2000. The origin of the Woyla Terranes in Sumatra and the Late Mesozoicevolution of the Sundaland margin. Journal of Asian Earth Sciences 18, 713–38.2) Barber A. J. & CROW M. J. 2003. Evaluation of plate tectonic models for the developmentof Sumatra. Gondwana Research 20, 1–28.3) Barber A. J., CROW M. J. & MILSOM J. S. (eds) 2005. Sumatra: Geology, Resources andTectonics. Geological Society Memoir 31. Geological Society of London, London.4) Barber A. J. & CROW M. J. 2009. Structure of Sumatra and its implications for the tectonicassembly of Southeast Asia and the destruction of Paleotethys : 2 Island Arc (2009) 18, 3–205)Chibber, H.L., 1934, The Geology of Burma : New Jersy, Prentice-Hall, Inc6)Curay J.R., Moore D.G., Lawver L.A., Emmel F.J., Raitt R.W., Henry M. & Kieckhfer R. (1979).– Tectonics of the Andaman Sea and Burma. In: T.S. Watkins, L. Martadet & P.W. Dickerson,Eds, Geological and geophysical investigations of continental margins. AAPG Mem., 29, 189-198.7) Curray, J.R. 2005. Tectonics and history of the Andaman Sea region. Journal of Asian EarthSciences, 25, 187-232.8) Gerven.M.van. and Pichler.H., 1995, Some aspects of volcanology and geochemistry ofthe Tengger Caldera, Java, Indonesia : Eruption of a K-rick tholeitic series, Jour. SE AsianEarth Sci. V.1, No.2, P.125-1339) Gupta, A.K and Yagi,K., 1980, Minerals and rocks . V.14; Petrology and genesis of lucite –bearing rocks. Sprimger- Verlag, Newyork

45

Page 46: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

10) Hutchison, C.S., 1989. Geological Evolution of Southeast Asia. Oxford University Press.11) Khin Maung Tun, 1993, Petrology of the Shin Ma Taung Area, Pakkoku Tsp., Univ. ofMandalay, unpub. Master’s thesis12) Maung Maung, Aung Naing Thu, Suzuki, H., 2008. Latest Jurassic radiolarian faunafrom the Chyinghkran area, Myitkyina Township, Kachin State (Region),13) Maury. R.C., et. al., 2004, Quaternary calc-alkaline and alkaline volcanism in an hyper-oblique convergence setting, central Myanmar and western Yunnan (Bull. Soc. géol. Fr.,2004, t. 175, no 5, pp. 461-472)14) Metacalfe I. 1996. Pre-Cretaceous evolution of SE Asian terranes. In Hall R. & BlundellD. J. (eds).Tectonic Evolution of Southeast Asia. Geological Society, London, SpecialPublication 106, 97–122,Geological Society of London, London.15) Metacalfe I. 2005. Asia: South-East. In Selley R. C., Cocks L. R. M. & Plimer I. R. (eds).Encyclopedia of Geology, pp. 169–96. Elsevier, Amsterdam.16) Mitchell, A.H.G., 1981. Phanerozoic plate boundaries in mainland SE Asia, theHimalayas and Tibet. Journal of the Geological Society, London 138, 109–122.17) Mitchell, A.G.H. 1989. The Shan Plateau and WesternBurma: Mesozoic-Cenozoic plateboundaries and correlation with Tibet. In: Sengör, A.m.C. (ed.)Tectonic Evolution of theTethyan Region. KluwerAcademic Publishers, 567-583.18) Morrison, G.W. 1980, Charcteristics and tectonic setting of the shoshonite rockassociation : Lithos, 13, P. 101-12.19) Naing Maw Than, 1993, Petrology of the Taungni-Pingadaw Area, Kyaukpadaung Tsp.,Univ. of Mandalay, unpub. Master’s thesis

46

Page 47: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

20) Naing Maw Than, 2012, Nature of the Central Volcanic Line in Taung Ni area, CentralMyanmar (Presented at AOGS 1012, Asia Oceania Geoscience Society, August 2012,Singapore)21) Ni, James F. Marco, Gunzman Speziale et al.,1989, Accreationary tectonics of Burmaand the three dimensional geometry of the Burma subduction zone: Geology, No.17, P.68-71.22) Marshall.T.R, Amos.B.J. & Stephenson.D, 1983, Base Metals Concentrations inSilicified and Argilized lavas of the The central Burma Volcanics (Geological Society,London, Special Publications 1983, V 11, P.59-68.)23) Oo,TIN H. & NYUNY H. 2002. Permian of Myanmar.Journal of Asian Earth Science 20,683–9.24) Stephenson, D. and Marshall.T.R. , 1984, The petrology and mineralogy of Mt. Popavolcano and the nature of the late Cenozoic Burma volcanic arc; Jour Geology. SocietyLondon, V.141, P.747-762.25) United Nations, 1978c. Geology and Exploration Geochemistry of the Salingyi-Shinmataung area, Central Burma. Technical Report No. 5, DP/UN/BUR-72-002/14,Geological Survey and Exploration Project, United Nations Development Programme.United Nations, New York, p. 29.26) Win Swe (2012) The Tectonic Evolution Of Myanmar: A Brief Overview, GEOSEA 2012(Bangkok, Thailand)27) Ye Min, 1992, Petrology of the Banmauk-Pinlebu Area, Kawlin-Wuntho Tsp., Univ. ofMandalay, unpub. Master’s thesis

47

Page 48: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Back Up

48

Page 49: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

A) SOUTH SOUTH

CHINA CHINA

INDIA

INDIAv Transhimalayan arc

· ·· Yarlung Tsangpa-lrrawaddy·

1....~~......;;;;;;..~~~~~~~M.;.;.;.;;id~d~le~E~o~c~e~ne.;;..;;;c.~4~0~M~a;;..i~M~id~d~le;.:.;.M~io~.c.~..e~~-n-~-e'~Fig. 5. Paleogeographic reconstruction. A. Schematic reconstruction of rivers and suture zonesfor Late Eocene time (c. 40 Ma). Note the major rivers, including the Tsangpo–Irrawaddysystem, run parallel to the orogen. The continuous Transhimalayan arc includes the Gangdesebatholith, eastern Transhimalayan batholiths and the Mogok Metamorphic Belt and SlateBelt of Myanmar. B. During Early Miocene time (c. 20 Ma), the Tsangpo–Irrawaddy river keepspace with deformation around the syntaxis. C. By the Middle Miocene (c. 15 Ma), theYarlung Tsangpo–Irrawaddy river has disconnected, and the Yarlung Tsangpo has been capturedby the Lohit River (a tributary of the modern Brahmaputra). Namche Barwe is onlyshown to locate position of the syntaxis. Tectonic reconstructions and position of theWest

49Burma block relative to the Lhasa terrane and SE Asia are based on Hall (2002) and Metcalfe

Page 50: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

90° 110°

China

ust Maler strike-slip fault

zones~ 20°: SMS

•.. •

•:

:NUS

7 :

. : LS•••••

Tersang, located along the Bentong-Raub Suture

Zone (RBS)

500 km

Regional Setting

IndiaMai

spreading centre

and Sewell Rises

Attenuated continental cr ene oceanic crust

Pliocene-Holocene oceanic crust 0 1 = Gaoligong Shear zone

2 = Chongshan Shear zone3 = Ailao Shan-Red

River hear zone4 = Sagaing Fault zone

s = Mae Ping Fault zone6 = Three Pagodas Fault zone7 = Ranong Fault zone8 = Khlong Marui Fault zone9 = West Andaman Fault zone10 = Sumatra Fault zone

·•

SSukhothai Zone

lnthanon Zone

Region underlain by accretedc oceanic crust, western ntains Woyla Terranes and

Mawgi NappeTerranes derived from Gondwana in the late Early Permian

••: Suture zones

MSS = Myitkyina Suture 10° ASS= Ailao Shan SutureMES= Menglian SutureSMS = Song Ma Suture CMS= Chiang Mai Suture NUS= Nan-Uttaradit Suture MS= Mae Sariang SutureLS = Loei SutureSKS= Sa Kaeo SutureRBS = Rharb Benthong Suture

ISibumasu (Shan-Thai) Terrane

Terranes derived from Gondwanalandin

Indochina Terrane

South China Terrane

• West Burma Terrane

Regional tectonic setting of the gold deposit (Sone and Metcalfe 2008)

50

CM = ChiangL = Lancang

.,/ Modem

• Alcock

Attenuor Mioc

• Pliocen

Sukhot

lnthan

Region Mesozoi edge co Mawgi

Terranes deriv the late Early P

Sibum

Terranes der the Devonian

Page 51: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.6South China

N

Andaman 10Sea

Mesozoic

• volcanic arc___ Terrane

boundary------- ( nferred)X X X Suture4 4 Active trench

6 6 Thrust & extinct trench

Here is thesimple

subdivision

Terranes of

Cathaysian

affinity and

Gondwana

affinity,

DD

Terranes separated fromGondwanaland in Devonian

Terranes separated fromGondwanaland inEarly PermianTerranes separated from Gondwanaland in Late Triassic-Jurassic

India separated fromGondwanaland in Cretaceous

into

~~

depending uponwhen they

separated from

Gondwanaland.

Cathaysian

terranes are

characterised by

the equatorial

Gigantopteris

flora while

Gondwana

affinity terranes

contain glacial

pebbly

mudstones in

the

Carboniferous•

~~

~~

Blocks _se_Parated fromAustraha m Cenozoic

Blocks of East Asia resulting from South China Sea Tertiary riftingName

sof numbered terranes '

horsts or continental1 = Hainan Island2 = Sikuleh

3 = Paternoster4 = Mangkalihat5 = West Sulawesi6 = Semitau7 = Luconia8 = Kelabit-Longbawan9 = Spratly Islands

fragments

oo

(Dangerous Grounds)10 = Reed

Bank11 = North Palawan12 = Paracel Islands13 = Macclesfield BankC-M = Changning-

Menglian

Suture 100°

fragments, terranes and principal sutures of South-East Asia redrawn from

120° Perm ian 51Fig. 14.1. Distribution of continental

blocks,=W=ak=1ta~a~n~d~M~et~ca~lf~e~(2~00~5~)-~~~~~~~~~~~~~~~~~~~~-·~~~..~..~..~..._..J....

I

Page 52: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.7) SE Asia Regional Tectonic Map with Major Cpmponents Terranes & Fold Belts

SE Asia regionaltectonic mapshowing majorcomponent terranesand fold belts.SRTM data fromhttp://srtm.csi.cgiar.org/; geological mapmodified after e.g.,Barber and Crow(2003), Metcalfe(2013) and Burrett etal. (2014).

52

Page 53: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

Fig.8 110"China

ust

,::, ' 0

,,,c:

,,,E SMS

'~ 'e- ' '~ ' '

'

:,V'I

'\

\I I I

I •I :I :I •

II

IIII\\

SOOkm

---

-Outline of Sundaland

Modem spreading centre

Alcock and Sewell Rises

Attenuated continent.al cr or Miocene oceanic crust

Major strike-slip fault zones1 = Gaoligong Shear Zone2 = Chongshan Shear Zone3 = Ailao Shan-Red River

Shear Zone4 = 5againg Fault ZoneS = Mae Ping Fault Zone

20•

Pliocene-Holocene

oceanic crust

Sukhothai Zonelnthanon Zone

Region underlain by accreted Mesozoic oceanic crust. western edge contains WoylaTerranes and Mawgyi Nappe

Terranes derived from Gondwana in the late Early Permian

6 = Three Pagodas Fault Zone7 = Ranong Fault Zone8 = Khlong Marui Fault Zone9 • West Andaman Fault Zone10 = Sumatra Fault ZoneSuture zones

MSS = Myitkyina Suture 10-ASS= Ailao Shan Suture MES ~ Menglian Suture SMS = Song Ma Suture CMS = Chiang Mai SutureNUS= Nan-Urtaradit Suture

Sibumasu (Shan-Thai) Terrane

Terranes derived from Gondwanaland in the Devonian• Indochina

TerraneMS = Mae Sariang

SutureLS = Loei SutureSKS = Sa Kaeo Suture

• South China Terrane

· • West lkirma

Terrana6RS = Bento

-Raub Suture

Geological terrane map of SE Asia (modified fromSearle & Morley 2011) and the distribution of the Sukhothai and lnthanon zones in orthemand SE Thailand proposed by Sonc & Metcalfe (2008) (a. Khlong Lan Bend in the Mac Ping Fault Zone: b. Mae

Yuan Fault).53

CM= Chiang MaiL= Lancang

Cenozoic basin

Page 54: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

..Fig.10

.. li

If,

'

\Andaman SIBUMA.,. Sea BLOC

"

54

l

Page 55: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

97" 98" 100° 102"

PRE-TERT ARY TECTON C UN T0 100 200---======i

EAST SUMATRA BLO (SIBUMASU)

Triassic D Kaloiunconformity

Permo-Ca~boniferous ~ Alas Li(Tapanuh Group) ~ Bohor

(pebbly

MSTZ

WOYLANAPPE

Jurass c- D Woyla

Group retaceous

mestone)- 104°

104°

I I I S IN SUMATRAkm

5'

CK

, Batumilmil, Kualu

mestone (Visean)

ok, Tigapuluh Group mudstones)

Medial SumatraTectonic Zone

3'

2'

,.

o-Island arc and accretionary

1•

Permian D Palepat, Mengkarang

I

data from the 1:250000 geological map sheets published

Fig. 5

Distribution of the pre-Tertiary stratigraphic and tectonic units in Sumatra, based onby the Indonesian Geological Research and Development Centre, Bandung (after Barber et al 2005). Darker

tones indicate areas of outcrop, lighter tones indicate that the pre-Tertiary is overlain by Tertiary and Quaternary sedimentary and volcanic rocks.

55

95°E

S'N

3'

1•

i

O' C

complex

WEST SUMATRA BLOCK

i-s

(CATHAYSIAN)

Triassic D Tuhur

unconformity

Carboniferous0 Kluet, Kuantan (with Visean li

95°E 96" 97" 98" 99'

1 oo

Page 56: Tectono-magmatic Development of Accreted West Burma Block from Gondwana Land-Igcp sept 2014 waseda

ACCRETIONARY

BLOCK

Bintan Formationr-----~--~-•n•o

(oceanic and volcanic

enc,

:-::,:>

~:,-

-ai ea

~·c

en and Kualu ............

..............................................

,.

<a:w

::::>0

w!=

Formations

limestones)-c

a:

Fig. 6

Stratigraphic relationships between tectonic and stratigraphic units in Sumatra and East Malaya. Triassic rocks in similar facies extend across theEast Malaya, West Malaya-East Sumatra (Sibumasu) blocks, the Medial Sumatra Tectonic Zone and the West

Sumatra block and that all tectonic units arecut by Triassic and younger granites (after Barber et al 2005).

56

WOYLAGROUPWEST SUMATRA BLOCK

(Schiefer Barisan, Vorbarlsan, Kluet and

Kuantan UnHs)

MSTZ

WEST MALAYAEAST SUMATRA

(SIBUMASU)

BENTONG-BILLITON

COMPLEX

en::::>0

ow

~a:

Granitic Intrusions

Granitic Intrusions

u,

jj

!

Granitic Intrusions

----·--------· ...-----·-···---··--

•-•n•Hn-•-••·~

?

?...... ..................................

.

WoytaGroup

arc assemblages)

............................................

Limestone blocks in melange

Qen~

oen$a:I-

SiMup & TuhurFormations

,.

.................. --·-···--·--···-·

Situtup, Silungkang, Palepat and Mengkarang

Formations(tropical Jambi flora)

5

s: Et-=5...... u.....

a,:::,0ex:(!)

-zce

-z

c(/)

:::::,

w e,

Semanggol, Kodlang

Kaloi, Batumilmil

.......F..o...r.m...a..t.i.o..n..s....

··-··-····--······-·-·····

Kaloi and Batumilmil Formations

(.) "!l

=-1

Tempilang

....

Formation ....

-· ........ ··-.....................

....

z~

Q.

~IiJ-

••·············•····················

Pemali Group

a.:::::,0a:e:J:::::,z

~

~ .... 8ryozoen Bed

Bohorok (tilloids) and Alas

Formations (temperate fauna

in limestones)

en

a:

sz

<3

Kluet and Kuantan

(tropical fauna in