Stewart (1988) -- L Proterozoic n' Paleozoic S Margin of N. a. n the Accretion of Mexico

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Geology

doi: 10.1130/0091-7613(1988)0162.3.CO;21988;16;186-189Geology

John H. Stewartaccretion of MexicoLatest Proterozoic and Paleozoic southern margin of North America and the

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Latest Proterozoic and Paleozoic southern marg in

o f Nor th Amer ica and the accre t ion o f Mex ico

John H. Stewart

U.S. Geo log ica l Survey M .S. 901 345 M idd le f ie ld Road Men lo Park Ca l i f o rn ia 94025

A B S T R A C T

Th e la t es t Pro terozo ic an d Pa leozo ic s ou th ern marg in o f th e

N orth A mer ican con t in en t i s in t erp reted to h ave b een loca ted in w h at

i s n o w n orth ern M ex ic o . Th e in t erp reta t ion is b as ed on 1 ) th e con -

vergen ce acros s n orth ern Mex ico o f th e C ord i l l eran geos yn c l in a l b e l t

on th e w es t t ow ard th e Ou ach i ta geos yn c l in a l b e l t on th e eas t , an d

2) th e lack o f N orth A mer ican u p p ermos t Pro terozo ic an d Pa leozo ic

s h e l f an d cra ton a l p la t form rock s s ou th o f la t 28 in Mex ico . C omp lex

rift ing in the lates t Pr oter ozo ic to Cambria n is interpre ted to hav e

forme d th e s ou th ern marg in an d may h ave p rod u ced microcon t in en ta l

b lock s n ow rep res en ted b y Precamb rian crys ta l l in e b as emen t rock s in

eas t ern Mex ico an d p os s ib ly e l s ew h ere in th e C ar ib b ean reg ion .

Precamb rian crys ta l l in e rock s , a s s oc ia t ed Pa leozo ic s ed imen tary

rock s , an d p erh ap s far - t rave led exo t ic t erran es w ere accre ted to

N orth A mer ica in th e la t e Pa leozo ic , an d p erh ap s Tr ia s s ic , an d

formed th e n u c leu s o f Me x ico .

I N T R O D U C T I O N

In recent years speculat ion has increased that the southern margin of

th e N o r th A mer ican co n t in en t ex ten d ed ac r o s s n o r th e r n M ex ico d u r in g

lates t Prote rozoic and Paleozoic t ime Ross , 1976; S tew ar t , 1976, 1981;

P e i f f e r - R an g in , 1 9 7 9 ; S tev en s , 1 9 8 2 ; P a lmer e t a l . , 1 9 8 4 ; A lmazan -

Vazquez et a l . , 1986) . In th is ar t ic le I review information on the locat ion of

th i s p r o p o s ed mar g in , ex p la in s eemin g ly an o malo u s P r ecamb r ian an d P a -

leozoic rocks south of the proposed margin , and descr ibe the tectonic

d ev e lo p men t o f th e s o u th e r n mar g in o f N o r th A mer ica an d th e acc r e t io n

of Mexico.

L O C A T I O N O F T H E S O U T H E R N M A R G I N

Th e b o u n d ar y b e tw een s h a l lo w - w a te r mio g eo s y n c l in a l an d c r a to n a l

pla tform carbon ate-s i l ic iclas t ic rocks and f r inging eugeosyn cl inal se-

quen ces of deep-w ater s i l iceous and de tr i ta l rocks def ines the la tes t

P r o te r o zo ic an d P a leo zo ic co n t in en ta l mar g in o f N o r th A mer ica . Th i s

bou nda ry F ig . IB) , modif ied by thrus t ing, t rends eas t in the Cord i l leran

g eo s y n c l in a l b e l t o f n o r th w es t M ex ico an d h as an i r r eg u la r b u t g en e r a l ly

s o u th w es t t r en d in th e O u a ch i t a g eo s y n c l in a l b e l t o f th e s o u th e r n U n i t ed

S ta te s . Th e co n v er g en ce o f th es e tw o b e l t s to w ar d o n e an o th e r h as l ed to

the specula t ion that they jo in in a region of few outc rops of Paleo zoic

rocks in nor thern Mexico. This hypothes is is suppor ted by facies and

thickness t rends of Paleozoic rocks that extend general ly eas t across the

s o u th e r n an d s o u th w es te r n U n i t ed S ta t e s an d n o r th e r n M ex ico S tev en s,

1982; Palmer et a l . , 1984; Almazan-Vasquez et a l . , 1986) and by souther ly

La te P r o te r o zo ic an d C amb r ian p a leo cu r r en t s th a t s ug g es t a f low o u tw a r d

f r o m th e N o r th A m er ican p la t f o r m to w ar d a s o u th e r n s he l f S tew ar t e t a l ,

1984, F ig . 14) . The hypothes is is a lso suppor ted by the widespread dis tr i -

b u t io n o f u p p e r mo s t P r o te r o zo ic an d P a leo zo ic s h a l lo w - w a te r s h e l f r o ck s

F ig . A , I B ) in th e U n i t ed S ta t e s an d n o r th e r n M ex ico a s f a r s o u th a s l a t

28, and the lack of any shal low-water rocks that can be t ied with assur-

anc e to the No rth Am erica n shelf south of th is la t i tude S tew ar t , 1981) .

S p ecu la t io n o n th e lo ca t io n o f th e s o u th e r n mar g in o f N o r th A me r ica

is in ter related with the problem of the amount , i f any, of Mesozoic or

younger tectonic d is locat ions in nor thern Mexico. In par t icular , 700 to 800

k m o f J u r as si c d i s p lacemen t o n th e l e f t - la t e r a l M o ja v e - S o n o r a meg as h ea r

F ig . 1 ) h as b een p r o p o s ed b y S i lv e r an d A n d er s o n 1 9 7 4 ) an d A n d er s o n

an d S ch m id t 1 9 8 3 ) . Th i s in t e r p r e ta t io n is b as ed o n an ap p a r en t d i s r u p t io n

in n o r th w es t M ex ico o f P r ecamb r ian c r y s ta l l in e b as emen t r o ck s an d th e

s eemin g ly id en t i ca l d i s r u p t io n o f u n co n f o r mab ly o v e r ly in g u p p er mo s t

P r o te r o zo ic an d P a leo zo ic C o r d i l l e r an g eo s y n c lin a l r o ck s F ig . 1 A , I B ) .

Th e m eg as h ea r i s an imp o r tan t b o u n d ar y b e tw een d i f f e r en t ty p es of r o ck s

an d s t r u c tu r es in n o r th e r n M ex ico F ig . 1 ) an d , a s s u ch , may r ep r es en t a

zone of s ignif icant la teral movement . On the o ther hand, the al ignment of

th e C o r d i l l e r an an d O u ach i t a b e l t s F ig . 1 ) may a r g u e ag a in s t s u ch mo v e-

men t s . I n an y cas e , t ec to n ic d i s lo ca t io n s in n o r th e r n M ex ico a r e p o o r ly

unders tood, and s ignif icant d is rupt ions in the relat ive pos i t ions of rocks

and s tructures sho wn in F igure 1 are poss ible .

P R E C A M B R I A N A N D P A L E O Z O I C R O C K S S O U T H

O F T H E P R O P O S E D M A R G I N

P r ecamb r ian c r y s ta l l in e b as emen t r o ck s an d P a leo zo ic s ed imen ta r y

an d m e tam o r p h ic r o ck s c r o p o u t , o r h av e b een p en e t r a t ed in d r il l h o le s , a t

s ca t t e r ed lo ca l i t i e s in M ex ico s o u th o f th e p r o p o s ed s o u th e r n mar g in o f

l a t e s t P r o te r o zo ic an d P a leo zo ic N o r th A m er ica F ig . 1 A , IB , 1 C ) . S o me

geologis ts have proposed that the Ouachita bel t turns south in nor theas t

M ex ico A n d er s o n an d S ch m id t , 1 9 8 3 ; H an d s ch y e t a l. , 1 9 8 7 ) an d th a t th e

P r ecamb r ian an d P a leo zo ic r o ck s in M ex ico f o r m a s o u th w ar d - ex ten d in g

p r o n g o f th e N o r th A me r ican co n t in en t G u zm an an d D e C s e r n a , 1 9 6 3 ;

Shurbet and Cebull , 1987) . Such relat ion, i f t rue, would be in conf l ic t with

the concepts presented here.

The mos t impor tant local i ty south of the proposed margin is the

H u izach a l - P e r eg r in a a r ea in eas t e r n M ex ico F ig . I B ) w h er e P r ecam b r ian

G r en v i l l i an b as emen t r o ck s an d S i lu r i an , D ev o n ian , M is s i s s ip p ian , P en n -

s y lv an ian , an d P e r mia n s ed imen ta r y r o ck s c r o p o u t C ar r i l lo - B r av o ,

Figure 1. Surface and subsurface distribution of Precambrian to

Triassic rocks, southern United States and central and northern Mex-

ico. MC = Mexico City; MSM = Mojave-Sonora megashear; CA = Cali-

fornia; MX = Mexico; SA = San Andreas fault system; TX = Texas; US =

United States. Symbols queried where facies assignments or ages are

uncertain. Blank areas are no-data regions. A: Precambrian crystalline

rocks. HP = Huizachal-Peregrina anticlinorium; HU = Huayacocotla an-

ticlinorium. Based mainly on Condie 1981), Anderson an d Silver

1979), and Bickford et al. 1986 ). B: Uppermost P roterozoic to Lower

Mississippian. HP = Huizachal-Peregrina anticlinorium; M = Marathon

region; OB = Ouachita be lt; TA = transcontinental arch. Based on many

sources, including Gastil and Miller 1984), Stewart et al. 1984), Flawn

et al. 1961), and Lopez-Ramos 198 1,19 82). C: Upper Mississippian to

Middle Triassic. OB = Ouachita belt; PB = Pedregosa basin; S = serpen-

tinite; V = volcanic rock. Based on many sources, including Gastil and

Miller 1984 ), Lopez-Ram os 1972, 1981, 1982), Mellor and Breyer

1981), and H andschy et al. 1987). D: Upper Triassic. Based on

many sources, including Belcher 1979) and Lopez-Ram os 1972,

1981,1982).

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3/5

E X P L A N A T I O N

M e s o z o i c o r C e n o z o i c s t r ik e - s li p f a u l t A r r o w s s h o w

r e l a t i v e m o v e m e n t

A g e , i n M a

1700 1800

1550 1770

1340 1400

750 1200


U p p e r P a l eo zo i c o r T r i ass i c (? ) t h ru s t f au l t D ash ed w h ere

i n f e r red . S aw t ee t h o n u p p er p l a t e

M e s o z o i c o r C e n o z o i c s t r i ke - s li p f a u l t A r r o w s s h o w


^ / . yv j C ra t o n a l p l a t f o rm

. . * . C o rd i l l e ran m i o g eo syn c l i n a l b e l t

l i ^ ^ l S i l ic e o u s a n d d e tr i ta l ( e u g e o s y n c l in a l ) a s s e m b l a g e s


. U p p er P a l eo zo i c o r T r i ass ic ( ? ) t h ru s t f au l t D ash ed w h ere

i n f e r red . S aw t ee t h o n u p p er p l a t e






C h i n le F o r m a t i o n a n d D o c k u m G r o u p

C ra t o n a l p l a t f o rm

C o rd i l l e ran m i o g eo syn c l i n a l b e l t

T h i ck f l ysch seq u en ces ; l i t t l e ch er t

T h i n f l y s c h s e q u e n c e s ; c o m m o n t o a b u n d a n t c h e r t

T u rb i d i t e seq u en ce o f P ed reg o sa b as i n

l . - . i y . j C o arse r i f t - b as i n d ep o s i t s

j ^ j j M a r i n e s e d i m e n t a r y ro c k s

I - - V ^ l G ran i t o i d ro cks

U p p er P a l eo zo i c m et am o rp h i c ro cks , i n c l u d i n g i n t e r i o r

zo n e o f O u ach i t a b e l t

G ran i t o i d ro cks

GEOLOGY, February 1988

187


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1961). These rocks have been correlated Flaw n et al., 1961; Carrillo-

Bravo, 1961) with Paleozoic rocks of the Marathon region of southwest

Texas, and this correlation has been given as evidence that the Ouachita

geosynclinal belt extends southwar d into northeast M exico Flaw n et al.,

1961; Carrillo-Bravo, 1961). This correlation, however, seems unlikely

because the lower Paleozoic sedimentary sequence there does not closely

resemble that of the Mara thon region. In particular, Silurian and Devon ian

strata consist of gravity-flow deposits with a transported shallow-water

fauna, unlike any rocks in the Marathon region. In addition, rocks in the

Huizachal-Peregrina area that were previously reported as Devonian no-

vaculite, a distinctive unit in the Ouachita geosynclinal belt, are now

identified as volcanic rocks of unkn ow n age Gursky and R amirez-

Ramirez, 1986).

Farther south, Precambrian crystalline basement and Paleozoic sedi-

men tary rocks occur in the subsurface of eastern Mexico Lopez -Ram os,

1972), in the Huayacocotla anticlinorium, and in Oaxaca in southern

Mexico south of the area of Fig. 1). The only Paleozoic shallo w-w ater

rocks in this region that could conceivably be considered to be a piece of

the North American shelf occur in Oaxac a Pantoja-Alor and R obison,

1967). Here, however, the stratigraphic sequence is unlike that of the

North American shelf, and Cambrian trilobite faunas in this sequence have

their greatest affinities to faunas in Argentina Robison a nd Panto ja-Alo r,

1968).

T E C T O N IC D E V E L O P M E N T O F T H E S O U T H E R N

M A R G I N O F N O R T H A M E R I C A

Latest Proterozoic to Early Mississippian

The latest Proterozoic and Paleozoic southern margin of North

America is interpreted to have formed either during a single Late Proter-

ozoic rifting event Keller and Cebull, 1973; Stewart, 1976) or during tw o

stages of rifting, one in the late Precambrian and one in the Cambrian

Lowe, 1985). In the latter interpretation, microcontinental blocks sepa-

rated from North America during the Cambrian, migrated away from

North America, and in their wake produced basins in which the rocks of

the Ouach ita belt were deposited. Subsequ ent to the rifting event or

events), the margin remained generally tectonically passive into the

Mississippian.

This passive margin in northwest Mexico is a continuation of the

Cordilleran belt of western North America and is characterized by an

outward-thickening sequence of shallow-water shelf deposits of the mio-

geosynclinal belt Stewar t et al., 1984) and offshelf deep-w ater siliceous

and detrital rocks of the eugeosynclinal belt Poole and Madri d, 19 86).

Deposition of these sequences was interrupted in Nevada by a major

converge nt event Antler orogeny) in latest Dev onian and M ississippian

time, but no rocks or structures related to this event have yet been recog-

nized in northwest Mexico.

The Ouachita belt contrasts with the Cordilleran belt because it lacks

an outward-thickening miogeosynclinal sequence. In the Ouachita belt,

th in cratonal platform rocks extend southward to the thrust contact with

the tectonically overlying siliceous and detrital eugeosynclinal) rocks on

the south Flaw n et al., 1961; Nicholas and Rozen dal, 1975; Greenw ood

et al., 1977). Miogeosynclinal sequences comparable to the Cordilleran

belt may exist at depth south of the thrust contact Lillie et al., 1983;

Palmer et al., 1984), but the thickness and distribution of these rocks

cannot be determined with available information.

Late Mississippian to Middle Triassic

During the late Paleozoic, the southern margin of North America

becam e tectonically active. Flysch sequences Fig. 1C) as thick as 10 km

were deposited in the Ouachita belt and emplaced in a major a llochthon

over coeval shelf carbo nate rocks Flawn et al., 1961) during the en-

chroachment and final coll is ion of South America and North America

during the late Paleozoic Ouachita orogeny. A widespread allochthon of

upper Paleozoic metam orphic rocks interior zone of the Ouachita belt)

was also emplaced during this time. In northeastern and eastern Mexico,

thinner and finer grained sequences of upper Paleozoic flysch Lopez-

Ram os, 1981 ,1982), as well as upper Paleozoic metam orphic rocks Gar-

rison et al., 1980; Hand schy et al., 1987), serpentinite Carrillo-Brav o,

1961), volcanic rocks Lopez-R amos, 1981, 1982), and poorly dated

Perm ian to Triassic granitic rocks Lopez -Ram os, 1972; Handschy et al.,

1987) occur in scattered outcrops and in the subsurface. Rocks in north-

east Mexico, north of the Mojave-Sonora megashear, were considered by

Handschy et a l . 1987) to be a composite terrane composed of la te Paleo-

zoic voclanic-arc rocks and exotic continental crust, accreted to North

America during the Ouach ita orogeny.

In north-central Mexico, upper Paleozoic turbiditic rocks are exposed

in the Pedregosa basin Mellor and Breyer, 1981; Gree nwo od et al., 1977),

but these rocks depositionally overlie lower Paleozoic carbonate shelf

rocks, in contrast to the Ouachita belt where similar rocks depositionally

overlie siliceous and detrital offshelf rocks. Armin 1987 ) ascribed the

southern Pedregosa basin to Early Permian downflexure under northward-

moving thrust sheets during the Ouachita orogeny in north-central

Mexico.

In northwest Mexico, upper Paleozoic turbiditic sequences also over-

lie lower Paleozoic eugeosynclinal rocks Poole and Madrid, 1986) similar

to the stratigraphic relations in the Ouachita belt, although the turbiditic

sequences are much thinner in northwest Mexico than in the Ouachita

belt . Deformation in northwest Mexico occurred between the mid-

Permian and the Late Triassic and resulted in the emplacement of a major

allochthon of Paleozoic eugeosynclinal and turbiditic rocks over Paleozoic

carbon ate shelf rocks R. Amay a and T. Calm us, 1987, oral com mun .).

A paleogeographic continuity from North America across Mexico to

South America resulted from late Paleozoic tectonic events. This conti-

nuity is evident fron the similarity of upper Paleozoic faunas between and

in the tw o continen ts Ross, 1979; Stevens, 1982; Ande rson and Sch midt,

1983).

Late Triassic

By Late Triassic time the assembly of much of Mexico may have

been complete. In northeast Mexico, assembly of accreted terranes appar-

ently was complete by Early Permian time when the thrust systems of the

Marathon region stopped moving and definite ly before emplacement of

Triassic plutons in northeast Mexico Hand schy et al., 1987). In north-

western Mexico, Upper Triassic rocks that rest unconformably on

allochthonou s eugeosynclinal terranes contain coarse, locally derived detri-

tus from North Am erican shelf rocks, indicating the juxtapos ition of the

accreted rocks and North America by Late Triassic time. These and other

Upper Triassic rocks in northern Mexico appear to have accumulated in

rift basins Belcher, 1979; Stewar t and Roldn, 1986) suprajacent to the

accreted terranes.

T E C T O N I C M O D E L

The model presented here is an attempt to integrate various ideas

concerning the geologic development of the North American continent

and Mexico, and it incorporates the idea that the Late Proterozoic and

early and middle Paleozoic southern margin of North America extended

across northern Mexico. If the margin was there, most of Mexico has been

accreted to the North American continent during or since late Paleozoic

time.

The southern margin of North America, as interpreted here, was

developed by Late Proterozoic and Ca mbr ian rifting that may have taken

place in tw o stages Low e, 1985). Durin g the second stage, small mic ro-

continental blocks may have r if ted from North America and form what

are now Precamb rian baseme nt terranes in eastern Mexic o Fig. 1A) and

perhaps elsewhere in the Caribbean region. Little is known of the history

of these blocks; some may have remained close to North America, others

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may have t rave led fa r from North America , and s t i l l others may have been

derived from other cont inents . Whatever the i r or igin, these blocks were

assembled and a t tached to North America , or enmeshed in the col l i s ion

z one be t we e n Nor t h Am e r i c a a nd Sou t h Am e r i c a dur i ng t he l a t e Pa l e o-

zoic , and perhaps the Early and Middle Triass ic . Orogenic ac t ivi ty tha t l ed

to thi s assembly occurred from Miss i ss ippian to Permian t ime in the Oua-

chi ta be l t in the southern Uni ted Sta tes and northeas te rn Mexico and from

Permian to perhaps Triass ic t ime in north-cent ra l and northwest Mexico.

Assembly of the various blocks may have been comple te by Late Triass ic

t ime wh en r i f t bas ins for me d in the tec tonica l ly w eak be l t tha t was the s i t e

of the la te Pa leozoic and perha ps Triass ic accre t ion Stewart and Rold n,

1986). This same zone of weakness corresponds in part to the s i t e of the

prop osed la rge-sca le l e f t - l a te ra l di splacemen t a long the Jurass ic Mo jave-

Sonora m e ga she a r .

R E F E R E N C E S

CITED

Almazan-Vazquez, Emilio, Palmer, A.R., and Robison, R.A., 1986, Constraints on

the southern margin of North America during the early Paleozoic: Geological

Society of America Abstracts with Programs, v. 18, p. 525.

Anderson, T.H., and Schmidt, V.A., 1983, The evolution of Middle America and

the Gulf of M exico-Caribbean Sea region during M esozoic time: Geological

Society of America Bulletin, v. 94, p. 941 -966 .

Anderson, T.H., and Silver, L.T., 1979, The role of the Mojave-Sonora m egashear

in the tectonic evolution of northern Son ora,

in

Anderson, T.H., and Roldn-

Quintana , J., eds., Geology of northern Sonora Geological Society of Amer-

ica Annual Meeting guidebook, field trip 27): Pittsburgh, Pennsylvania,

University of Pittsburgh, p. 59 -68 .

Armin, R.A., 1987, Sedimentology and tectonic significance of Wolfcampian

Lower Permian) conglomerates in the Pedregosa basin: Southeastern Arizona,

southwestern New Mexico, and northern Mexico: Geological Society of Amer-

ica Bulletin, v. 99, p. 42- 65.

Belcher, R.C., 1979, Depositional environm ents, paleomagnetism, and tectonic sig-

nificance of Huizachal red beds lower Mesozoic), northeastern Mexico [Ph.D .

thesis]: Austin, University of Texas, 276 p.

Bickford, M.E., Van Schmus, W .R., and Zietz, Isodore, 1986, Proterozoic history of

the midcontinent region of North Am erica: Geology, v. 14, p. 492- 496 .

Carrillo-Bravo, J., 1961, Geologa del anticlinoria Huizachal-Peregrina al NW de

Ciudad Victoria, Tamaulipas: Asociacin Mexicana de Geolgos Petroleros,

Boletn, v. 13, p. 1-9 8.

Condie, K.C., 1981, Precambrian rocks of the southwestern United States and

adjacent areas of Mexico: New Mexico Bureau of Mines and Mineral Re-

sources, Resource Map 13, scale 1:1,640,000.

Flawn, P.T., Goldstein, August, Jr., King, P B., and W eaver, C.E., 1961 , The

Ouachita System: University of Texas Publication 6120,401 p.

Garrison, J.R., Jr. Ramirez-Ramirez, C., and Long, L.E., 1980, Rb-Sr isotopic

study of the ages and provenance of Precambrian granulite and Paleozoic

greenschist near Ciudad Victoria, Mexico,inPilger, R.H., Jr., ed., The origin of

the Gulf of Mexico and the early opening of the central north Atlantic ocean:

Baton Rouge, Louisiana State University, p. 37 -49 .

Gastil, Gord on, and Miller, Richard, 1984, Prebatholithic paleogeography of Penin-

sular California and adjacent Mexico,

i n

Frizzell, V., ed., Symposium on Baja

California: Society of Economic Paleontologists and Mineralogists, Pacific

Section, p. 9-16.

Greenwood, Eugene, Kottlowski, F.E., and Thompson, Sam, III, 1977, Petroleum

potential and stratigraphy of Pedregosa Basin: Comparison with Permian and

Orogrande basins: American Association of Petroleum Geologists Bulletin,

v. 61, p. 1448-1469.

Gursky, Hans-Jiirgen, and Ramirez-Ramirez, Calixto, 1986, Notas preliminares

sobre el discubrimiento de volcanitas acidas en el Caflon de Caballeros

Ncleo del Anticlinorio Huizachal-Peregrina, Tamaulipas, Mxico): Actas de

la Facultad de Ciencias de la Tierra, Universidad Autnom a de Nuevo Leon,

Linares, v. 1, no. 1, p. 11-22.

Guzman, E.J., and D e Cserna, Zoltan, 1963, Tectonic history of Mexico,inChilds,

O.E., and Beebe, B.W., eds., Backbone of the Am ericas, a symposium: Ameri-

can Association of Petroleum Geologists Memoir 2, p. 113-1 29.

Handschy, J.W., Keller, G.R., and Smith, K.J., 1987, The Ouachita system in

northern Mexico: Tectonics, v. 6, p. 32 3-3 30.

Keller, G.R., and Cebull, S.E., 1973, Plate tectonics and the Ouachita system in

Texas, Oklahoma, and Arkansas: Geological Society of America Bulletin,

v. 84,p. 1659-1666.

Lillie, R.J., Nelson, K.D., DeVoogd, B Brewer, J.A., Oliver, J.E., Brown, L.D.,

Kaufm an, S., and Viele, G.W., 1983, Crustal structure of Ouachita M ountains,

Arkansas: A model based on integration of COCORP reflection profiles and

regional geophysical data: American Association of Petroleum Geologists Bul-

letin, v. 67, p. 907-931.

Lopez-Ramos, E., 1972, Estudio del basamento igneo y metamorfico de las zonas

norte y Poza Rica entre Nautla, Ver., y Jimnez, Tamps: Asociacin M exicana

de Geolgos Petroleros, Boletn, v. 24, p. 2 65- 323 .

1981, Geologa de Mxico, Toma III second edition): Mexico, D.F., Tesis

Resendiz S. A., 446 p.

1982, Geologa de Mexico, Tom a II third edition): Mexico, D.F., Tesis Re-

sendiz S. A., 454 p.

Lowe, D.R ., 1985, Ouachita trough: Part of a Cambrian failedrift system Geology,

v. 13, p. 790-793.

Mellor, E.I., and Breyer, J.A., 1981, Petrology of late Paleozoic basin-fill sand-

stones, north-central Mexico: Geological Society of America Bulletin, v. 92,

part I, p. 367-373.

Nicholas, R.L., and Rozendal, R.A., 1975, Subsurface positive elements with Oua-

chita foldbelt in Texas and their relation to Paleozoic cratonic margin: Ameri-

can Association of Petroleum Geologists Bulletin, v. 59, p. 193-216.

Palmer, A.R., DeMis, W.D., Muehlberger, W.R., and Robison, R.A., 1984, Geo-

logic implications of Middle Cambrian boulders from the Haymond Forma-

tion Pennsylvanian) in the Marathon basin, west Texas: Geology, v. 12,

p. 91-94.

Pantoja-Alor, Jerjes, and Robison, R.A., 1967, Paleozoic sedimentary rocks in

Oaxaca, Mexico: Science, v. 157, p. 1033-1035.

Peiffer-Rangin, Franoise, 1979, Les zones isopiques du Palozoque inferior du

nord-ouest mexicain, tmoins du relais entre les Appalaches et al cordillre

ouest-amricaine: Paris, Acadmie des Sciences Com ptes Rendus, v. 288, sr.

D, p. 1517-1519.

Poole, F.G., and Madrid, R.J., 1986, Paleozoic rocks in Sonora Mexico) and their

relation to the sou thwestern continental m argin of North America: Geological

Society of America Abstracts with Programs, v. 18, p. 7 20.

Robison, R.A., and Pantoja-Alor, Jerjes, 1968, Tremadocian trilobites from the

Nochixtln region, Oaxaca, Mexico: Journal of Paleontology, v. 42,

p. 767-800.

Ross, C.A., 1979, Late Paleozoic collision of North and South A merica: Geology,

v. 7, p. 41-44.

Ross, R.J., 1976, O rdovician sedimentation in the western United States,

in

Bassett,

M.G., ed., The Ordovician System: Proceedings of the Paleontological Associ-

ation Symposium, B irmingham, September 1974: Cardiff, University of W ales

Press and National Museum of Wales, p. 73-105.

Shurbet, D.H., and Cebull, S.E., 1987, Tectonic interpretation of the westernmost

part of the Ouachita-Marathon Hercynian) orogenic belt, west Texas-Mexico:

Geology, v. 15, p. 458^161.

Silver, L.T., and A nderson, T.H., 1974, Possible left-lateral early to middle Meso-

zoic disruption of the southwestern N orth America craton m argin: Geological

Society of America Abstracts with Programs, v. 6, p. 955.

Stevens, C.H., 1982, The Early Permian hysanophyllumcoral belt: Another clue to

Permian plate-tectonic reconstructions: Geological Society of America Bul-

letin, v. 93, p. 798-803.

Stewart, J.H., 1976, Late Precambrian evolution of North America: Plate tectonic

implication: Geology, v. 4, p. 11-15 .

1981, Early and middle Paleozoic margin of the North A merican continent in

the southwestern United States and northern Mexico,

i n

Howard, K.A., Carr,

M.D., and Miller, M.D., eds., Tectonic framework of the Mojave and Sonora

deserts, California and Arizona: U.S. Geological Survey Open-File Report

81-503, p. 101-103.

Stewart, J.H., McMenamin, M.A.S., and Morales-Ramirez, J.M., 1984, Upper

Proterozoic and Cambrian rocks in the Caborca region, Sonora, Mexico

Physical stratigraphy, biostratigraphy, paleocurrent studies, and regional rela-

tions: U.S. Geological Survey Professional Paper 1309, 36 p.

Stewart, J.H., and Roldn Q., Jaime, 1986, Upper Triassic rift basins in northern

Mexico: New information from the Barrance Group: Geological Society of

America Abstracts with Programs, v. 18, p. 764.

A C K N O W L E D G M E N T S

I thank R. Amaya-Martinez, T. H. Anderson, T. Calmus, M. F. Campa,

R. Dyer, C. Gon zales-Leon, Gordo n G astil, P. C. Goodell, H. J. Gursky, A. E . Guz-

man, N. W. Jones, K. B. Ketner, R. J. Madrid, J. W. McKee, I. Minjarez-Sosa,

J. M . Morales-Ramirez, F. G. Poole, C. Ramirez-Ramirez, J. R oldin , G. Salas, and

L. T. Silver for their help in my geologic studies; C. Carter, R. C. Douglass, J. T.

Dutro, Jr., A. G. Harris, B. Murchey, A. R. Palmer, J. E. Repetski, R. J. Ross, Jr.,

and B. R. Ward law for their paleontologic help; and J. E . Case, W. R. Muehlberger,

R. A. Robison, and Paul Stone for helpful reviews of the manu script.

Manuscript received August 10,1987

Revised manuscript received October 26,1987

Manuscript accepted November 4, 1987

GEOLOGY February 1988

Printed in U.S.A.

189

Documents

Stewart (1988) -- L Proterozoic n' Paleozoic S Margin of N. a. n the Accretion of Mexico