Plate Tectonic Reconstructions of the Cretaceous and Cenozoic Ocean Basins

Tectonophysrs, 155 (1988) 27-48 Elsevier Science Publishers B.V.. Amsterdam - Printed in The Netherlands

Plate tectonic reconstructions of the Cretaceous and Cenozoic ocean basins

CHRISTOPHER R. SCOTESE I, LISA M. GAHAGAN ’ and ROGER L. LARSON ’

’ Shell Deuelopment Co.. Beilarre Research Center, P.O. Box Ml. Houston. TX 77001 (U.S.A. I ’ The Department ofGeological Soences, The Unwer.r# of Texas. Austtn. TX 7X713 (l!S.A.) and The Instrtutefor Geophvsics. Universit,: of Texcrs, Austrn. TX 78759 (U.S.A.) -’ School of 0ceanograph.v. Uniuerslt_v of Rhode Island, kbgston, RI 0_‘8XI (U.S.A.)

(Received May 18, 1987: revised vrersion accepted September 8. 19x7)

Abstract

Scotese. C.R.. Gahagan. L.M. and Larson, R.L.. 1988. Plate tectonic reconstructions of the Cretnceous and Cenozoic ocean basins. In: C.R. Scotese and W.W. Sager (Editors), Mesozoic and Cenozoic Plate Reccm\tructions. Tectonophysics. 155: 27-48.

In this paper we present nine reconstructions for the Mesozoic and Cenozoic. based on previously published sea-floor spreading tsochrons*. The purpose of this study was (1) to determine if the isochrons could he refitted to produce accurate plate tectonic reconstructions. (2) to identify areas of apparent mismatch between magnetic iaochrons as a focus for further investigations, and (3) to test the capabilities and accuracy of interactive computer graphic methods of plate tectonic reconstruction. In general. Tertiary and Late Cretaceous isochrons could be refitted wtth little overlap and few gaps: however. closure errors were apparent in the vicinity of the Bouvet and Macquarie triple Junctions. It was not possible to produce Early Cretaceous reconstructions that were consistent with the previously published isochrons. In this paper we also propose that the Late Cretaceous and Early Tertiary plate reorganizations ob\erved in the Indian Ocean were the result of the progressive subduction of an intra-Tethyan rift system.

Introduction ceous (chron MO, 118.7 Ma) and Early Cretaceoua (chron M17, 143.8 Ma). The isochrons were drawn In 1985 a map illustrating the age of the ocean using published and unpublished magnetic basins and continents was published by Larson et anomalies and bathymetric information. and were al. (1985) (Fig. l), on which the oceans were modified to take into account new data from divided into colored regions bounded by magnetic Seasat altimetry (Haxby, 1985). This map super- isochrons representing the following geologic time cedes the maps of the age of the ocean floor intervals: Pleistocene (chron 2, 1.9 Ma), Pliocene published by Pitman III et al. (1974) and Sclater (chron 3a, 5.9 Ma), Miocene (chron 6b, 23 Ma), et al. (1981). Oligocene (chron 15, 37.7 Ma), Eocene (chron 25. In this study, we have used interactive com- 59.2 Ma), Paleocene (chron 29, 66.2 Ma), Late puter graphics to produce plate tectonic recon- Cretaceous (chron 34, 84.0 Ma), Middle Creta- structions for each of the sea-floor spreading isochrons described by Larson et al. (1985). The ____ goals of this investigation were (1) to determine if * Larson et al. (1985). the isochrons mapped by Larson et al. could be

0040.1951/88/$03.50 ‘1’)1988 Elsevier Science Publishers B.V. Fig. 1. Isochron map illustrating the age of the ocean basm.s (modified after Larson et al., 1985). Fine light stipple-chrons 1. 3a and 6, fine dark stipple-chrons 15 and 25. coarse light stipple- --chrons 29 and 34, coarse dark stipple---chrons MO and Ml?. Continental sutures after Scotese et al. (1979), Ziegler et al. (1983) and Ross and Scotese (this issue).

refitted to produce accurate plate tectonic recon- digitizing program was to convert X and Y map structions, (2) to identify the areas of apparent coordinates into coordinates of latitude and longi- mismatch between magnetic isochrons as a focus tude, the program also recorded important infor- for further study and (3) to test the capabilities mation that was used to build a geographic data- and accuracy of interactive computer graphic base. This database consisted of bibliographic in- methods of plate tectonic reconstruction. In the formation as well as a description of the age of the following sections we outline the methods used to feature, the plate with which it was travelhng, and produce the reconstructions, discuss how well the a simple coded description of the feature that was isochrons can be refitted, review the major plate being digitized (for example, BA = bathymetric tectonic events illustrated in Figs. 3-11, and con- contour, RI = spreading ridge, CS = coastline, sider the predictions made for relative plate mo- etc.). This information was later used by data tions across complex plate circuits. management programs that searched and sorted the data, and by the interactive computer graphics M&hods and map-making programs that rotated and plotted the data as a function of plate identifica- Digitization of map data and interactive computer tion and age. graphics After the map data had been digitized, the geographic data was displayed and m~ipulated The first step in our procedure was to encode using the Evans and Sutherland PS300 interactive map data into digital form. This was done using a computer graphics system and the Megadrifter large digitizing tablet and a computer program program (MI. Ross and CR. Scotese). This pro- that converted X and Y map coordinates into gram displays geographic information in three di- latitude and longitude coordinates (Scotese and mensions on the surface of the globe. The user Eaker, 1975). Although the main function of the visually determines best-fitting rotations by inter- 29

b 60 B’N

C 55 ?N

Fig. 2. Contour piot representing a surface whose peak is the location of best-fittmg Euler poles for the closure of South Atlantic isochrons for (a) chron 25, (b) chron 15 and (c) chron 6. The star represents the Euler poIe determined using interactive graphic>. the dot is the location of the best-fitting Euler pole determined using the method of McKenzie and Sclater (1971). Pilger (1978) and Pattiat (1983).

actively manipulating dials that control the loca- Gruphicul test of the best fit tion and amount of rotation about finite rotation poles (LePichon et al.. 1973). By rotating the dials The computer graphic approach described and adjusting the finite rotation pole, isochrons above represents a novel way of making plate can he visually superimposed, and in a matter of reconstructions. However, it is reasonable to en- minutes, a visual best fit can be determined. quire “how well can the isochrons be recon- The main advantages of interactive computer structed using this technique?” To answer this graphics for plate reconstructions are (1) it is question, the rotations that were determined visu- possible to test all possible plate tectonic reassem- ally using the interactive computer graphic method blies in a matter of minutes, (2) reconstruction of were compared with best-fitting rotations that were multiple plates simultaneously is possible, and (3) determined by iterative statistical techniques. In the production of plate reconstructions that in- Fig. 2, the locations of the best-fitting rotations tegrate both marine- and land-based information determined by the interactive computer graphics is enabled. At present, the main disadvantage of method (star) can be compared with the location the method is that there is no numerical quantifi- of the best~fitting rotations (dot) calcufated by cation of the goodness of fit.

_ _,- .-_-I_lI,”

34 35 ‘-

ai % -E -0 . 39 iterative statistical methods (McKenzie and Late Tertiary: Chrons 2, 3a und 6h (Figs. 3. 4 and Sclater, 1971; Pilger Jr., 1978; Patriat, 1983). 5) Figure 2a is a contour plot that represents a surface whose peak is the location of a finite There is generally a good fit of the magnetic rotation pole (54.80”N-31.80’W) that best fits isochrons that were used to produce the re- chron 25 on the African plate with its counterpart constructions for the Late Tertiary (chrons 2. 3a on the South American plate. Similar contour and 6b). The only areas of notable misfit occur plots of the best-fit surface were made for chron along the northwestern extension of the Central 15 and chron 6 in the South Atlantic (Figs. 2b and Indian Ridge in the Arabian Sea. between the c). In both cases. the finite rotation pole de- Nazca and Pacific plates. and in the vicinity of the termined by the interactive computer graphic triple junction between Australia. Antarctica and method falls close to the calculated best-fit pole. the Pacific plates, south of Macquarie Ridge. We feel that this graphic test indicates that the The major tectonic events during the Late Ter- rotations determined by the interactive technique tiary (Figs. 3, 4 and 5) include the continued are comparable to results obtained using iterative northward motion of India and Australia; the statistical techniques, and that we are justified in opening of the Red Sea (Cochran, 1983: Hemp- using this method to produce plate reconstruc- ton, 1987: Labrecque and Zitellini, 1985). the Gulf tions. However. we agree that a combination of of California (Larson et al.. 1968: Atwater, 1970) these techniques might be the best approach, and and the Sea of Japan (Otsuki and Ehiro. 1979); are planning to modify the computer graphics the convergence and sinistral strike-slip movement software in the near future so that estimates of the along the Alpine Fault in New Zealand (Kamp, goodness of fit can be calculated interactively. 1986) and the breakup of the Farallon plate to form the Cocos and Nazca plates (Menard. 1978; Wortel and Cloetingh. 1981). The evolution of the Caribbean region is based on recent syntheses by Pindell and Barrett (1987) and Ross and Scotese Mesozoic and Cenozoic plate tectonic reconstruc- (this issue). tions In Figs. 3-5. it is interesting to note the apparent widening gap between the subduction zone Figures 3-11 illustrate the opening of the mod- and the oceanic crust south of Indonesia and ern ocean basins during the Cretaceous and Ter- along the entire margin of the Pacific. The re- tiary: a map has been produced for each of the construction of Southeast Asia shown in Fig. 5 is a magnetic isochrons illustrated on the Larson et al. preliminary attempt to palinspastically restore the (1985) map. The age of the ocean floor is indi- severe and complex deformation that resulted from cated by the varying densities of the stipple pat- the collision of India with Asia in the Early Ter- terns and the mismatch of isochrons along the tiary. No attempt has been made to reconstruct. in ridges is indicated by black (overlaps) and white detail, the tectonic evolution of the Scotia Sea or (gaps) areas. The blank regions on the map repre- the marginal basins of the western Pacific. sent areas of oceanic crust that have been removed by subduction. Eat+ Tertiacv: Chrons 15 und 25 (Figs. 6 and 7) The continental outlines and the location of sutures illustrated in Fig. 1 are taken from Scotese In Fig. 6 (chron 15. 37.7 Ma) there are wide et al. (1979) and Ziegler et al. (1983). The entire gaps between the isochrons east of the Bouvet plate reconstruction has been reoriented with re- triple junction in the South Atlantic and between spect to the spin axis using the global apparent the isochrons in the vicinity of southeastern polar wander path of Ziegler et al. (1983). The Australia, south of the Tasman Rise. These prob- crosses that have been plotted on the continents lem areas persist in the chron 25 reconstruction represent a present-day 5 o graticule. where additionally a wide gap occurs between the North and South Islands of New Zealand. This triple junction and along the Southwest Indian gap does not appear in older or younger re- Ridge near the Prince Edward Fracture Zone (Fig. constructions and is probably the result of errors 9). There is also a gap between northwestern India within the Pacific-Antarctic-Australia-New Zea- and the African plate, and the Indian plate over- land plate circuit. Also problematic is the gap laps both Madagascar and Antarctica in the area between the Indian and Antarctic plates just to of the Central Indian Ocean triple junction. the west of Broken Ridge. The gap that appears In the North Atlantic region during the Late on the map between India and Africa represents Cretaceous, Iberia ceased to rotate with respect to the location of the Seychelles Islands and the Europe (A32, 73.5 Ma; Williams, 1975) and the Mascarene Bank. Labrador Sea began to open (the Quiet Zone, 95 The major tectonic events during the Early Ma; Srivastava and Tapscott, 1986). During this Tertiary (Figs. 6 and 7) include the collision of same time interval, the Central and South Atlantic India with Asia (A22, 50 Ma; Patriat and Achache, continued to widen and the spreading center in 1984) the first phase of rifting in the South China the Agulhas Basin jumped westward (A29, 66.2 Sea (Ru and Pigott, 1986) the termination of Ma; Labrecque and Hayes, 1979), aligning itself strike-slip motion along the Ninetyeast Ridge and with the overall N-S trend of the spreading axis the subsequent rapid separation of Australia from in the South Atlantic (Fig. 9). In the Indian Oc- Antarctica (A19, 44.1 Ma; Cande and Mutter, ean, along the Southwest Indian Ridge, the 1982; Stock and Molnar, 1987) the cessation of spreading direction changed from NE-directed sea-floor spreading in the Labrador Sea (A20,46.2 spreading (Fig. 8) to N-NW directed (Fig. 9)( Royer Ma; Srivastava and Tapscott, 1986) and in the et al., this issue). Further to the northeast, India Tasman Sea (A24, 56.1 Ma; Weissel and Hayes, rapidly drifted away from Madagascar, opening 1977) and the opening of the eastern North the Mascarene Basin (Fig. 8) and in the latest Atlantic (A24, 56.1 Ma; Srivastava and Tapscott, Cretaceous-earliest Tertiary the spreading center 1986). It was also during the Early Tertiary (Early in the Mascarene Basin jumped northward to a Eocene) that extension and sea-floor spreading location between India and the Seychelles (A28. began in the Cayman Trough, resulting in the 65.1 Ma; Schlich, 1982). As a result of this ridge eastward translation of the Caribbean plate rela- jump, the Seychelles were transferred to the Afri- tive to North and South America (Ross and can plate and the proximity of the spreading axis Scotese, this issue). During the Early Tertiary the to the margin of India may have triggered the Apulian “prong” of Africa collided with Europe eruption of the Deccan plateau basal& producing the Alps (Trumpy, 1982), and the west- In the eastern Indian Ocean and southwestern em Cordillera of North America was uplifted Pacific, rifting took place between Australia and during the Laramide orogeny (Coney. 1973). Antarctica (the Quiet Zone, 95 Ma; Cande and Mutter, 1982), New Zealand and Australia (A33, 80.2 Ma; Weissel and Hayes, 1977). and New Late Cretaceous: Chrons 29 and 34 (Figs. 8 and 9). Zealand and western Antarctica (the Quiet Zone, 95 Ma; Kamp, 1986; Stock and Molnar, 1987). Figures 8 and 9 illustrate the configuration of The initial spreading rate between Australia and the continents and the ocean basins during the Antarctica was slow (4.5 mm/yr) and a “leaky” Late Cretaceous. Although the isochrons in the plate boundary connected the Australian- Central Atlantic superimpose reasonably well, Antarctic rift with the Ninetyeast Ridge, which at there is a poor fit in the South Atlantic (Fig. 9), that time was a major strike-slip boundary be- especially in the vicinity of the Bouvet triple junc- tween the Indian and Australian plates. The tion. In the Indian Ocean, chron 29 can be recon- Kerguelen Plateau and Broken Ridge were pro- structed with only a small amount of misfit (Fig. duced as a result of excess volcanism along this 8); however, large gaps are apparent in the chron leaky plate boundary (Mutter and Cande, 1983; 34 reconstruction in the vicinity of the Bouvet Ramsay et al., 1986; Coffin et al., 1986). 41

Ear01 Cretaceous: Chrons MO and Ml 7 (Figs. 10 Ma; Markl, 1978; Larson et al.. 1979: Johnson et and 11) al., 1980; Veevers et al.. 1985a). Although no Early Cretaceous magnetic anomalies have been Although the Early Cretaceous isochrons in the mapped between India and Antarctica. it is likely Atlantic superimpose with little mismatch, the fit that India also separated from Antarctica at this of the isochrons in the Indian Ocean is not satis- time. factory. As illustrated in Fig. 10 there are large. Discussion unreconcilable overlaps between the isochrons on the Indian and Antarctica plates. and equally large Closure of triple junctions and across complex plate gaps ( > 500 km) between the isochrons on the circuits Antarctic and African plates. The problems are less severe for the chron Ml7 reconstruction; how- As the reconstructions in Figs. 3-11 illustrate, ever, a large overlap is evident between the iso- the isochrons of the Larson et al. (1985) map can, chrons in the Somali Basin. in most areas, be used to produce accurate and The breakup of Pangea began in the Middle informative plate tectonic reconstructions. Iso- Jurassic and continued into the Early Cretaceous. chrona in the North and Central Atlantic, and The breakup of North America and Africa was along the Southwest Indian Ridge can be recon- preceded by extension and rift-related volcanic structed with few gaps or overlaps. In the South activity that extended back into the earliest Atlantic and Central Indian Ocean, however. the Jurassic (Seidemann et al.. 1984) (the oldest iden- match between isochrons is not as good, especially tifiable magnetic anomaly in the Central Atlantic for the older reconstructions. is M25 (157 Ma; Klitgord and Schouten, 1986). The accuracy of the maps can also be evaluated but separation probably occurred somewhat earlier by observing the closure of plates around triple (around 180 Ma) in the Jurassic magnetic Quiet junctions. and by noting the predicted relative Zone. Similarly, the breakup of eastern and west- motion of plates across complex plate circuits ern Gondwana was signalled by the extrusion of (e.g., the motion of the Pacific plate relative to the extensive Karoo (Forster, 1975) and Ferrar North America). In Figs. 3-5 (Late Tertiary) (Kyle et al., 1981) basalts during the Early Jurassic: closure is good along all triple junctions, with the however, the oldest oceanic crust in the Somali exception of the triple junction south of the Mac- and Mozambique basins is Middle Jurassic in age quarie Ridge (Australia-India-Pacific). In the (M25, 157 Ma; Segoufin and Patriat. 1981). Early Tertiary and Late Cretaceous reconstruc- Sea-floor spreading in the South Atlantic and tions (Figs. 6-9). there is reasonable closure across between India and Antarctica appears to have the Central Indian triple junction (Africa--Antarc- been delayed until the Early Cretaceous. The oldest tica-India). and poor closure across the Kerguelen magnetic anomaly in the South Atlantic is Ml1 triple junction (Antarctica-Australia-India). (133.5 Ma; Rabinowitz and Labrecque, 1979), Closure is also poor across the Bouvet triple junc- suggesting that the basin began to open in the tion (Africa-Antarctica-South America) and the Valanginian (130 Ma). The Early Cretaceous Macquarie Ridge triple junction. opening of the South Atlantic is confirmed by the By refitting the isochrons. plate circuits can be presence of anomaly Ml2 (135.6 Ma: Goodlad et constructed that predict the relative motion be- al., 1982) in the Natal Valley, suggesting that the tween pairs of plates for which there can be no Falkland Plateau rifted away from southeastern direct measurement of relative motion. These Mozambique during the Valanginian. predictions are especially useful in areas, such as The timing of the separation of India from the Circum-Pacific Basin and the Tethys, where Antarctica and Australia is not as well con- subduction has removed vast areas of oceanic strained. Anomaly Ml0 in the Perth and Cuvier crust. Of particular interest are the predicted rela- Basin indicates that rifting between Australia and tive motions between the Pacific and North Greater India began in the Valanginian (133.5 America, and between Africa-India and Eurasia. 42

Pacific-North America relative motion collision of Greater India and Asia occurred during the Early Eocene, approximately 50 n1.y. ago It is interesting to note that during the Late (Patriat and Achache, 1984). Immediately follow- Cretaceous and Early Tertiary (Figs. 6-9) the ing the collision of India, spreading rates between distance between the center of the Pacific plate Australia and Antarctica increased, and Australia and the western margin of North America does rapidly separated from Antarctica (Figs. 3-6). not change significantly. This suggests that new Although this sequence of events is well docu- oceanic crust generated along the Farallon-Pacific mented, the causes of these changes in plate mo- spreading center (the modem East Pacific Rise) tion are not well understood. In Fig. 12, we have nearly balanced the amount of oceanic crust drawn hypothetical plate boundaries in the Tethys subducted beneath western North America. As Ocean. We propose that the progressive subduc- recorded in the bend of the Emperor-Hawaiian tion of these plate boundaries was directly re- hot-spot track, this situation changed abruptly sponsible for the plate tectonic reorganizations during the Late Tertiary when the Pacific plate observed to the south in the Indian Ocean. began to move rapidly to the northwest, parallel to Late Jurassic sea-floor spreading in the Somali the western margin of North America (Figs. 3-6). Basin records the breakup of eastern and western Gondwana (Segoufin and Patriat, 1981). It is in- Solution of motion across the Alpine Fault (New teresting to note that magnetic lineations in the Zealand) Argo abyssal plain along the northwest coast of Australia indicate that a tectonic element rifted The motion between the northern and southern from Australia at the same time (Larson, 1975; halves of New Zealand along the Alpine Fault was Heirtzler et al., 1978; Veevers et al., 1985b). Al- constrained by the plate circuit South New Zea- though the identity of this tectonic element is not land-Pacific-Marie Byrdland-eastern Antarcti- known with certainty, several authors have sug- ca-Australia-New Zealand. In our model, South gested that an island arc composed of western New Zealand was considered to be part of the Sula, Sumba and Timor rifted away from the Pacific plate and no subduction was presumed to northwestern margin of Australia in the Late have taken place along the southern margin of the Jurassic (Berry and Grady, 1981; Johnson, 1981; Campbell Plateau or along the northern margin of Parker and Gealey, 1985). When Gondwana is Marie Byrdland since the Late Cretaceous (95 reconstructed, the spreading directions in the Ma). Also, no attempt was made to palinspasti- Somali Basin are similar to those on the Argo tally restore the severly deformed shapes of North abyssal plain. As previous authors have suggested and South New Zealand. As illustrated in Figs. (Parker and Gealey, 1985) this similarity may 6-11, North and South New Zealand remained in indicate that these two spreading centers were the same relative positions during the Cretaceous once part of the same rift system (The Tethyan and Early Tertiary. From the reconstructions pre- Rift) (Fig. 12a). In the Late Jurassic, eastern sented here, it appears that major movement along Gondwana (Greater India and Australia) was the Alpine Fault did not begin until the Early located south of the Tethyan Rift; the “Neo- Miocene (Figs. 3-5). Tethyan plate” was located to the north of the spreading center (Fig. 12a). During the Late The closure of Tethys and plate reorganizations in Jurassic and Early Cretaceous, as new ocean floor the Indian Ocean was generated at the Tethyan Rift, the older parts of the Neo-Tethyan plate were subducted beneath As illustrated in Figs. 8-11, a wide Tethys the southern margin of Eurasia (Sengor, 1985). Ocean separated India from southern Asia during Sea-floor spreading along the Tethyan Rift con- the Early Cretaceous. During the Late Cretaceous, tinued during the Early Cretaceous and the Tethys narrowed as India rifted away from spreading center moved steadily northward (Fig. Madagascar and moved rapidly northward. The 12b). Rifting between India and Australia during NEO-TETHYAN PLATE

e) Fig. 12. Hypothetical plate boundaries in the Tethys dunng the Mesozox and Cenozoic. a. Early Cretaceoub (chron M17). b. Middle-Cretaceous (chron MO). c. Cretaceous magnetic Quiet Zone (= 95 Ma). d. Late Cretaceous (chron 34). e. PAxxene (chron 29). f. Oligocene (chron 15). the Early Cretaceous resulted in the formation of duction of the western part of the Tethyan Rift a new triple junction between the Indian, (Fig. 12~). As a consequence of the elimination of Australian and Neo-Tethyan plates (Fig. 12b). the western section of the Neo-Tethyan plate. the During the Middle Cretaceous, the Tethyan Indian plate began to be subducted beneath Rift continued to move northward as the Neo- Eurasia. We suggest that it was the initial subduc- Tethyan plate was subducted beneath Eurasia. We tion of the Indian plate that caused the breakup of propose that about 95 m.y. ago, a major plate India and Madagascar and resulted in the increase reorganization took place as a result of the sub- in spreading rates along the Central and Southeast Indian ridges. This plate reorganization may also ing of Mesozoic and Cenozoic plate motions. Be- have been responsible for the drastic changes in cause much of the data used to draw the isochrons spreading directions observed in the Wharton and were compiled between 1977 and 1983, it is inevi- Cuvier basins. In this region, during the Creta- table that more recent work will supercede and ceous Quiet Zone, spreading directions changed refine the plate tectonic model presented here by approximately 45” from N-NW (Wallaby and (Table 1). In this regard. these maps should be Perth fracture zones) to N-S (Ninetyeast Ridge viewed as a first draft that lays the groundwork and Investigator Fracture Zone). Our model would for future efforts. also predict that an important erogenic event took Although the Larson et al. (1985) sea-floor place along the southern margin of Eurasia during spreading isochrons work well for the Late Creta- the Middle Cretaceous as a result of the thermal ceous and Tertiary, the match of Early Cretaceous pulse generated by the subduction of the western isochrons in the Indian Ocean is unsatisfactory. section of the Tethyan Rift. The misfit between India, Africa and Antarctica As illustrated in Fig. 12c, we indicate that highlights an important problem that will require although the western section of the Tethyan Rift additional study. As pointed out in the text, other was subducted, the eastern part continued to gen- persistent problems include poor closure across erate ocean floor between Australia and Southeast the Macquarie and Bouvet triple junctions, misfit Asia. As illustrated in Figs. 12a-e, the distance along the Southwest Indian Ridge and the rnis- between northern Australia and Southeast Asia match of Late Cretaceous isochrons in the South remained relatively constant from the Late Jurassic Atlantic. through to the Early Tertiary, suggesting that there We also believe that this paper demonstrates was a balance between subduction and sea-floor that the interactive computer graphics method is a spreading. useful and effective tool for producing plate During the Late Cretaceous and Early Tertiary, tectonic reconstructions. The three-dimensional India moved rapidly northward as the Indian plate capabilities of the computer graphics display de- continued to be directly subducted beneath the vice (Evans and Sutherland PS300) combined with southern margin of Eurasia (Figs. 12d and e). In the ability to rotate and manipulate plate outlines the Early Eocene, Greater India collided with in “real time” allow the user to take full ad- Eurasia (A22, 50 Ma; Patriat and Achache, 1984). vantage of the plate tectonic paradigm. Because At about the time of the collision, and possibly as the graphics computer so easily handles the three- a direct result of it, spreading in the Wharton dimensional aspects, the user is free to integrate Basin stopped (A20, 46.2 Ma; Liu et al., 1983) and and synthesize the data using the most powerful the Indian and Australian plates were fused to image-processing device available-the human form the modem Indo-Australian plate. As in the brain. case of the Indian plate during the Late Cretaceous,the Indo-Australian plate began to be subducted directly beneath Eurasia. We suggest What have we learned?: Global synchroneity and “slab pull” as the major driving force of plate that it was the subduction of the Indo-Australian tectonics plate that caused the ultimate breakup of Australia and Antarctica, resulting in the increase in spreading rate along the Australia-Antarctica plate Finally, in any large-scale synthesis it is im- boundary (Cande and Mutter, 1982) portant to ask the question: “what new things have we learned?’ The greatest strength of any Conclusion historical science, such as geology, is the perspective that time brings. Looking at today’s world, we How well do the Larson et al. isochrons work? have only one example of the plate tectonic sys- These reconstructions represent a comprehen- tem; however, by reviewing the history of plate sive yet preliminary synthesis of our understand- motion during the Mesozoic and Cenozoic, we 45

may be able to discern patterns that are not Chron Time Lat. Long. Angle Reference apparent on a shorter time scale. (Ma)

A brief review of the model presented in this Spain relative to Eurasia paper emphasizes two major features of Mesozoic 29 66.2 0.00 0.00 0.00 and Cenozoic plate evolution: (1) global synchro- 34 84.0 -46.22 - 174.65 5.05 Closure 92.0 -50.08 -179.43 30.40 TABLE 1 Total finite poles of rotation India relative to Africa 2 1.9 -32.80 ~ 154.09 1.22 Chron Time Lat. Long. Angle Reference 3a 5.9 -35.39 ~ 149.70 3.35 (Ma) 6b 23.0 -17.27 - 133.98 12.23 North America relative to Africa 15 37.7 -15.25 -135.09 19.82 2 1.9 80.44 56.31 0.37 25 59.2 - 15.36 -144.40 34.27 3a 5.9 82.40 43.10 1.44 29 66.2 -12.48 - 147.79 46.56 6b 23.0 80.43 56.36 5.31 34 84.0 -18.72 -154.61 54.26 15 37.1 77.61 7.21 10.63 Closure 92.0 -21.28 -154.24 57.66 Lawver 25 59.2 79.10 7.07 17.05 and Scotese 29 66.2 80.59 - 14.76 22.50 (1987) 34 84.0 78.35 - 12.13 28.52 MO 118.7 66.41 - 19.61 54.12 Madagascar relative to Africa Ml7 143.8 67.07 - 18.05 59.23 MO 118.7 0.00 0.00 0.00 Ml7 143.8 2.21 -- 90.85 12.15 Greenland relative to North America (interpolated) 13 35.9 0.00 0.00 0.00 25 59.2 - 16.26 28.48 2.37 Australia relative to Antarctica 29 66.2 -41.70 35.94 5.14 15 37.7 ~ 13.70 - 151.21 21.69 34 84.0 - 39.63 30.94 7.91 25 59.2 -10.70 - 146.93 24.01 Closure 92.0 - 50.07 26.29 7.74 Lawver 29 66.2 - 1.64 - 144.23 26.43 and Scotese 34 84.0 - 8.93 ~ 150.11 26.54 (1987) Closure 95.0 - 1.58 - 140.98 31.29 Lawvrr and Scotese South America relative to Africa (1987) 2 1.9 68.75 - 41.47 0.62 3a 5.9 66.57 - 37.30 2.02 Antarctica relative to Africa 6b 23.0 52.67 - 31.64 7.71 2 1.9 18.55 - 36.41 0.33 15 37.7 55.85 - 32.83 14.32 3a 5.9 9.45 -41.72 0.82 25 59.2 55.85 - 32.83 21.62 6b 23.0 9.46 -41.70 3.34 29 66.2 55.87 - 32.83 25.13 15 37.7 8.73 - 36.52 5.93 34 84.0 59.77 - 35.40 33.13 25 59.2 -1.56 - 37.65 8.94 MO 11x.7 48.82 - 32.90 52.34 29 66.2 -2.82 - 42.18 11.46 Closure 138.0 44.50 - 32.20 58.20 Lawver 34 84.0 - 1.52 -- 40.03 17.23 and Scotese (1987) Antarctica relative to India 34 84.0 7.88 14.80 64.34 Eurasia relative to North America Closure 130.0 - 4.44 16.14 92.77 Lawver 2 1.9 ~ 65.85 - 41.56 0.43 and Scotese 3a 5.9 - 65.85 - 47.56 1.44 (1987) 6b 23.0 - 30.43 - 38.30 4.25 15 37.1 - 73.30 - 49.70 9.01 North New Zealand relative to Australia 25 59.2 - 43.50 - 34.60 12.39 50.0 0.00 0.00 0.00 29 66.2 - 65.43 - 32.04 16.35 25 59.2 5.26 - 24.14 0.73 34 84.0 - 65.83 - 22.85 19.33 29 66.2 9.67 - 38.82 7.31 Closure 92.0 - 69.34 - 33.20 23.61 Lawver Closure 95.0 24.19 ~ 19.91 44.61 Lawver and Scotese and Scotese (1987) (1987) TABLE 1 (continued) tion that followed the collision of India with Asia ______Chron Time Lat. Long. Angle Reference in the Early Eocene (A21; 50.3 Ma). (Ma) The synchroneity of these plate tectonic events

South New Zealand relative to Marie Byrdland has two important implications. The first is that 2 1.9 68.71 - 98.50 1.88 the plate motions are connected. What happens in 3a 5.9 75.84 - 60.93 6.46 one ocean basin or along one plate boundary 6b 23.0 73.35 - 62.84 16.62 affects surrounding plates, as well as plates on the 15 37.7 74.97 - 53.67 28.96 other side of the Earth. The nature of this connec- 25 59.2 71.40 - 59.57 38.28 29 66.2 69.78 - 58.86 46.14 tivity, however, is not well understood. The second 34 84.0 65.10 - 55.29 43.30 implication of synchroneity is that there is a dis- Closure 95.0 65.14 - 52.00 62.38 Lawver tinct cause, or trigger, that sets off the chain and Scotese reaction that we interpret as a major plate re- (1987) organization. We propose that plate reorganiza- Pacific relative to Marie Byrdland tions are triggered by the subduction of a major 2 1.9 68.71 - 98.50 1.88 ridge system, or by the elimination of a subduc- 3a 5.9 75.84 - 60.93 6.46 tion zone as a result of continental collision. The 6b 23.0 73.35 - 62.84 16.62 plate reorganizations that took place in the Indian 15 37.7 74.97 - 53.67 28.96 25 59.2 71.40 - 59.57 38.28 Ocean can easily be interpreted to follow this 29 66.2 69.78 - 58.86 46.14 pattern. 34 84.0 65.10 - 55.29 43.30 As mentioned above, the second major lesson Closure 95.0 65.14 - 52.00 62.38 Lawer to be learned from the pattern of Mesozoic and and Scotese Cenozoic plate motions is the importance of slab (1987) pull. Numerous authors have proposed that slab Nazca relative to the Pacific pull, or the force due to the negative buoyancy of 2 1.9 - 53.01 86.61 3.58 the old, cold lithosphere, is the major driving force 3a 5.9 -63.15 91.01 9.03 of plate tectonics. However. because the dynamics 6b 23.0 - 60.85 90.63 38.91 15 37.7 - 69.20 80.47 51.78 of plate motion are not well known, there is no 25 59.2 - 78.84 60.18 67.20 agreement regarding the importance of slab pull relative to the other proposed driving mechanisms. Cocos relative to the Pacific We believe that a review of the chronological 2 0.9 - 38.72 72.61 3.96 Minister 3a 5.9 -44.17 68.83 9.57 et al. (1974) development of plate motions during the Meso- zoic and Cenozoic clearly indicates that slab pull and geometry of subduction zones is the first-order cause of plate motions. As in the case of the neity of major changes in plate motion and (2) the reorganizations in the Indian Ocean, or the brea- importance of slab pull as the major driving force kup of the Farallon plate to form the Nazca and in plate tectonics. A brief review of the timing of Cocos plates, it is the events at the subduction changes in plate motion suggests that there have zone that produce changes in plate motion and been five major events during the Mesozoic and create new plate geometries. In contrast, it ap- Cenozoic. These events are: (1) the breakup of pears that spreading centers, although an im- Pangea and Gondwana during the Middle Jurassic portant component of the system, passively follow (the Quiet Zone, 175 Ma), (2) the breakup of the the lines of stress emanating from the trenches. southern continents (Africa-South America and Antarctica-Australia-India) during the Early Acknowledgements Cretaceous (Mll, 133.5 Ma), (3) the Middle Cretaceous plate reorganization (the Quiet Zone, The authors would like to thank Bill Gealey, 95 Ma), (4) the latest Cretaceous plate reorganiza- Jean-Yves Royer and Mark Gordon for their com- tion (A28; 65.1 Ma), and (5) the plate reorganiza- ments and reviews of the manuscript. We would 47 especially like to thank Kyle Winn and Nancy ern Indonesia, Vol. 2. Geol. Res. Dep. Cent. Spec. Publ., Killough for their help in preparing the figures. Minist. Mines and Energy, Bandung. 199 pp. Kamp. P.J.. 1986. Late Cretaceous-Cenozoic tectonic develop- This work was supported by funding from She11 ment of the Southwest Pacific Region. Tectonophysics. Development Co., Mobil Oil Co., Phillips Petro- 121: 225-251. leum, Elf Aquitaine, Conoco, Amoco Interna- Klitgord, K.D. and Schouten, H.. 1986. Ptatr kinematics of the tional Oil Co., Exxon Production Research, central Atlantic. In: P.R. Vogt and B.E. Tuchnlke (Editors). Chevron Overseas Petroleum Co. and Standard Thr Geology of North America. Vol. M. The Western North Atlantic Region. Geol. Sot. Am.. Boulder, Cnlo.. pp. Oil Co., as part of their sponsorship of the Paleo- 351-378. ceanographic Mapping Project at the University Kyle, P.R., Elliot, D.H. and Sutter. J.F.. 1981. Jurasstc Ferrar of Texas. Supergroup tholeiites from the tramantarctic mountains. Antarctica. and their relationship to the inittal fragmentation of Gondwana. In: M.M. Cresswell and D. Vella (tidi- References tora). Gondwana Five. Proc. Int. Gondwana Symp.. 5th (Wellington. New Zealand. li-16 February. 1980). Bal- Atwater, T.. 1970. implications of plate tectonics for the kema, Rotterdam. pp. 283-288. Cenozoic evolution of Western North America. Geol. Sot. Labrecque. J.L. and Hayes, D.E.. 1979. Seafloor spreading Am. Bull.. 81: 3513-3536. history of the Agulhas basin. Earth Planet. Sci. Lett., 45: Berry, R.F. and Grady, A.E., 1981. Age of the major orogene- 411-42X. sis in Timor. In: A.J. Barber and S. Wiryosujono (Editors). Labrecque, J.L. and Zitellini. N., 1985. Continuous sea-floor The Geology and Tectonics of Eastern Indonesia. Vol. 2. spreading in the Red Sea: an alternative interpretation of Geoi. Res. Dep. Cent. Spec. Publ.. Minist. Mines and magnetic anomaly patterns. Am. Assoc Pet. Grol. Bull.. Energy. Bandung, 171 pp. 69: 513-524. Cande. SC. and Mutter, J.C.. 1982. A revised identification of Larson. R.L., 1975. Late Jurassic sra-floor spreadmg in the the oldest sea-floor spreading anomalies between Australia eastern Indian Ocean, Geology, 3: 69-71. and Antarctica. Earth Planet. Sci. Lett.. 58: 151-160. Larson. R.L.. Menard, H.W. and Smith. S.M., 1968. A result of Cochran, J.R.. 1983. A model for development of the Red Sea. ocean-floor spreading and transform faulting. Sctrnce, lhi: Am. Assoc. Pet. Geoi. Bull., 67: 41-69. 7X1-784. Coffin. M.F., Davies, H.L. and Haxby, W.F.. 1986. Structure Larson. R.L., Mutter, J.C.. Diebold. J.B.. Carpenter. G.B. and of the Kerguelen plateau province from Seasat altimetry Symonds, P.. 1979. Cuvier Basin: A product of ocean crust and seismic reflection data. Nature. 324: 134-136. formation by Early Cretaceous rifting off western Australia. Coney. P.J., 1973. Non-collision tectogenesis in western North Earth Planet. Sci. ILett.. 45: 105-l 14. America. In: D.H. Tarling and SK. Runcorn (Editors), Larson. R.L.. Pitman III, W.C.. Gnlovchmko. X.. Cande, S.C.. Implications of Continental Drift to the Earth Sciences, Dewey. J.F.. Haxby. W.F. and Labrrcque. J.L.. 1985. The Vol. 2. .Academic Press, London, pp. 113-121. Bedrock Geology of the World. Freeman, New York. Forster, R.. 1975. The geological history of the sedimentary Lawver. L.A. and Scotese. C.R.. 19X7. A revised reconstruction basins of southern Mozambique, and some aspects of the of Gondwana. In: G.D. McKenzie (Editor). Gondwana origin of the Mozambique Channel. Paleogeogr. Paleoc- Six: Structure. Tectonics, and Geophysics. Am. Geophys. limatol. Paieoecol.. 17: 267-287. Union, Geophys. Monogr., 40: 17-23. Goodlad, S.W., Martin, A.K. and Hartnady, C.J.H.. 1982. LePichon. X., Francheteau. J. and Bonin. J., 1973. Plate Mesozoic magmatic anomalies in the southern Natal Val- Tectonics. (Developments in Geotectnnics. 6.) Elsevier, ley. Nature, 295: 686688. Amsterdam, pp. 277-278. Haxhy, W.F., 1985. Gravity Field of the World’s Ckeans. Liu. C.S.. Curray. J.R. and McDonald. J.M.. 1983. New con- Lament-Doherty Geol. Obs., Palisades, N.Y. straints on the tectonic evolution of the eastern Indian Heirtzler, J.R., Cameron, P., Cook, P.J., Powell, T., Roeser. Ocean. Earth Planet. Sci. Lett.. 65: 331-342. H.A., Suk‘ardi, S. and Veevers. J.J.. 1978. The Argo abyssal Markl, R.G.. 1978. Further evidence for the early Cretaceous plain. Earth Planet. Sci. Lett.. 41: 21-31. breakup of Gondwanaland off southwestern Australia. Mar. Hempton, M.R.. 1987. Constraints on Arabian plate motion Geol., 26: 41-48. and extensional history of the Red Sea. Tectonics, 6: McKenzie, D.P. and Sclater. J.G.. 1971. The evolution of the 687-705. Indian Ocean since the late Cretaceous. Grophy. J.R. Johnson, B.D., Powell, CMCA. and Veevers, J.J., 1980. Early Astron. Sac.. 24: 437-528. spreading history of the Indian Ocean between India and Menard. H.W.. 1978. Fragmentation of the Farallon plate by Australia. Earth Planet. Sci. Lett.. 47: 133-143. pivoting subduction. J. Geoi.. 86: 999110. Johnson, C.R., 1981. Timor tectonics with implications for the Minster, J.B.. Jordan, T.H.. Molnar, P. and Haines. E., 1974. development of the Banda Arc. In: A.J. Barber and S. Numerical modelling of instantaneous plate tectonics. Geo- Wiryosujono (Editors), The Geology and Tectonics of East- phys. J.R. Astron. Sot., 36: 541lSlh. Mutter, J.C. and Cande, SC., 1983. The early opening between Sclater, J.G., Parsons, B. and Jaupart, C.. 1981. Oceans and Broken Ridge and Kerguelen Plateau. Earth Planet. Sci. continents: similarities and differences in the mechanisms Lett., 65: 369-376. of heat loss. J. Geophys. Res.. 86: 11535--l 1552. Otsuki. K. and Ehiro, M., 1979. Major strike-slip faults and Scotese. C.R. and Baker, D.W. 1975. Continental drift recon- their bearing on spreading in the Japan Sea. In: S. Uyeda, structions and animation. J. Geol. Educ.. 23: 1677171. R.W. Murphy and K. Kobayashi (Editors), Geodynamics Scotese, C.R., Bambach, R.K., Barton, C., Van der Voo. R. of the Western Pacific, Cent. Acad. Publ. Tokyo, pp. and Ziegler, A.M.. 1979. Paleozoic basemaps. J. Geol.. 87: 537-55s. 217-271. Parker, E.S. and Gealey, W.K., 1985. Plate tectonic evolution Segoufin, J. and Patriat, P., 1981. Reconstructions de I’Ocean of the Pacific-Indian Ocean region. Energy, 10: 249-261. indien occidental pour les epoques des anomalies M21, M2 Patriat, P., 1983. Evolution du systeme de dorsales de I’Gcean et 34. Paleoposition de Madagascar. Bull. Sot. Geol. Fr., indien. Ph.D. Thesis, Univ. Pierre et Marie Curie. Paris, 23(6): 603-607. 288 pp. Seidemann. D.E., Masterson. W.D., Dowling. M.P. and Patriat, P. and Achache, J., 1984. India-Eurasia collision chro- Turekian, K.K., 1984. K-Ar dates and 40 Ar/39 Ar age nology has implications for crustal shortening and driving spectra for Mesozoic basalt flows of the Hartford Basin, mechanisms of plates. Nature, 311: 615-621. Connecticut, and the Newark Basin, New Jersey. Geol. Sot. Pilger Jr., R.H., 1978. A method for finite plate reconstruc- Am. Bull., 95: 594-598. tions, with applications to Pacific-Nazca plate evolution. Sengor, A.M.C., 1985. The story of Tethys: How many wives Geophys. Res. Lett., 5: 469-472. did Okeanos have? Episodes, 8: 3-12. Pindell, J.L. and Barrett, S.F., 1987. Geological evolution of Srivastava, S.P. and Tapscott, CR., 1986. Plate kinematics of the Caribbean Region: a plate tectonic perspective. In: The the North Atlantic. In: P.R. Vogt and B.E. Tucholke (Edi- Geology of North America. Vol. I, The Caribbean Region. tors), The Geology of North America. Vol. M, The Western Geol. Sot. Am., Boulder, Colo., in press. North Atlantic Region. (A Decade of North American Pitman III, W.C., Larson, R.L. and Herron, E.M., 1974. Mag- Geology.) Geol. Sot. Am., Boulder, Colo., pp. 379-404. netic lineations of the oceans. Map Chart Ser., Vol. MC-6, Stock, J. and Molnar, P., 1987. Revised history of the early Geol. Sot. Am., Boulder, Colo. Tertiary plate motion in the southwest Pacific, Nature, 325: Rabinowitz, P.D. and Labrecque, J.L., 1979. The Mesozoic 495-499. South Atlantic and the evolution of its continental margins. Trumpy, R.. 1982. Alpine paleogeography: a reappraisal. In: J. Geophys. Res., 84: 5973-6002. K.J. Hsu (Editor), Mountain Building Processes Academic Ramsay, D.C., Colwell, J.B., Coffin, M.F., Davies, H.L., Hill, Press. London, pp. 149-156. P.J., Pigram, C.J. and Stagg, H.M.J., I986. New findings Veevers, J.J., Tayton, J.W. and Johnson, B.D., 1985a. Promi- from the Kerguelen plateau. Geology, 14: 589-593. nent magnetic anomaly along the continent-ocean Ross, M.I. and Scotese, C.R., 1988. A hierarchical tectonic boundary between the northwestern margin of Australia model of the Gulf of Mexico and Caribbean region. In: (Exmouth and Scott plateaus) and the Argo abyssal plain. C.R. Scotese and W.W. Sager (Editors), Mesozoic and Earth Planet. Sci. Lett., 72: 415-426. Cenozoic Plate Reconstructions. Tectonophysics, 155 (this Veevers, J.J.. Tayton, J.W. Johnson, B.D. and Hansen, L., issue): 139-168. 1985b. Magnetic expression of the continent-ocean Royer, J.Y., Patriat, P., Bergh, H.W. and Scotese, CR., 1988. boundary between the western margin of Australia and the Evolution of the Southwest Indian Ridge from the Late eastern Indian Ocean. J. Geophys., 56: 106120. Cretaceous (anomaly 34) to the Middle Eocene (anomaly Weissel, J.K. and Hayes, D.E., 1977. Evolution of the Tasman 20). In: C.R. Scotese and W.W. Sager (Editors), Mesozoic Sea reappraised. Earth Planet. Sci. Lett., 36: 77-84. and Cenozoic Plate Reconstructions. Tectonophysics, 155 Williams, C.A., 1975. Sea-floor spreading in the Bay of Biscay (this issue): 235-260. and its relationship to the North Atlantic, Earth Planet. Sci. Ru, K. and Pigott, J.D., 1986. Episodic rifting and subsidence Lett., 24: 440-456. in the South Schina Sea. Am. Assoc. Pet. Geoi. Bull., 70: Wortel, R., and Cloetingh, S., 1981. On the o~rigin of the 1136-1155. Cocos-Nazca spreading center. Geology, 9: 425-430. Schlich, R., 1982. The Indian Ocean: aseismic ridges, spreading Ziegler, A.M., Scotese, C.R. and Barrett, SF., 1983. Mesozoic centers, and oceanic basins. In: A.E.M. Nairn and F.G. and Cenozoic Paleogeographic maps. In: J.B. Borsche and Shehli (Editors), The Gcean Basins and Margins. Vol. 6, Sundermann (Editors), Tidal Friction and the Earth’s Rota- The Indian Ocean. Plenum, New York, pp. 51-147. tion II. Springer, Berlin, pp. 240-252.