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Eustatic Variations Reexamined

Bilal U. Haq, Smithsonian Institution, Washington, D.C., USA, and Sorbonne University, Paris, France

ABSTRACT INTRODUCTION documentation includes sections from the Documentation of eustatic variations for The Triassic Period encompasses 50.5 Sverdrup Basin, Svalbard, and the Barents Sea. This paper serves to complete a review the Triassic is limited by the paucity of the m.y., spanning an interval from 251.9 to of the entire as both preserved marine stratigraphic record, 201.4 Ma (Ogg et al., 2016). By this time, and sea-level variations have which is confined mostly to the low and the megacontinent of had already already been reappraised (Haq, 2014, 2017). middle paleolatitudes of the . assembled, surrounded by the For a background of the paleoenvironmental A revised sea-level curve based on reevalu- Ocean that covered >70% of Earth’s conditions (oceans and climates) in the ation of global stratigraphic data shows a surface, and by the mid-Triassic the Triassic see the GSA data repository (see clear trend of low seastands for an extended Pangaean landmass was almost evenly footnote 1). period that spans almost 80 m.y., from the distributed in the two hemispheres around latest to the earliest Jurassic. In the the paleo-equator (see Fig. S1 in the GSA 1 TRIASSIC TIME SCALE UPDATES Early and , the long-term Data Repository ). The interval from latest A succinct discussion of the method- sea levels were similar to or 10–20 m Permian through the earliest Jurassic, a ological advancements and modifications higher than the present-day mean sea level time span of nearly 80 m.y., represents the to the Triassic time scale can be found in (pdmsl). This trend was reversed in the late longest spell of low seastands of the Preto et al. (2010), and a detailed discussion , marked by a steady rise and cul- Phanerozoic. The Triassic is also bracketed of Triassic stratigraphy has been presented minating in peak sea levels of the Triassic by two major biotic near the by Ogg et al. (2014). Since the last update (~50 m above pdmsl) in the late . Permian-Triassic (P-T) and Triassic-Jurassic of the Triassic third-order sea-level varia- The trend reverses again with a decline in boundaries, the one at P-T boundary being the most severe biotic turnover of the tions (Haq and Al-Qahtani, 2005) that was the late and the base level remain- Phanerozoic (Raup and Sepkowski, 1982; calibrated to an earlier version of the time ing close to the pdmsl, and then Hallam and Wignall, 1997; McElwain et scale, there have been several refinements dipping further in the mid- to al., 1999). The experienced to the Triassic . The ~50 m below pdmsl into the latest Triassic the beginning of the lithospheric swell, latest version of the time scale (Ogg et al., and earliest Jurassic. Superimposed upon ushering the breakup of Pangaea and its 2016) modifies the boundaries of Triassic this long-term trend is the record of 22 eventual split into discrete continents in standard stages (ages) by anywhere widespread third-order sequence boundaries the later Mesozoic (see Fig. S1 [see footnote between <1 m.y. to almost 6 m.y. Like that have been identified, indicating sea- 1]). The definite signs of the beginning earlier versions, the new time scale is level falls of mostly minor (<25 m) to of Pangaean fragmentation were clearly mainly based on , anchored medium (25–75 m) amplitude. Only six of manifest by the end of the Triassic with the by selected radiometric dates, with some these falls are considered major, exceeding basaltic outpouring of the massive Central intervals refined by astronomical and the amplitude of 75 m. The long interval Atlantic magmatic province (see, e.g., cyclostratigraphical fine-tuning, and others of Triassic oceanic withdrawal is likely to Marzoli et al., 1999, 2004; Davies et al., aided by magnetostratigraphy. have led to general scarcity of preserved 2017). and ammonoids constitute the mainstay marine record and large stratigraphic In the past two decades substantial new of the Triassic biostratigraphic correlations. lacunae. Lacking evidence of continental stratigraphic data from Triassic sections Special problems concerning wider correla- ice sheets in the Triassic, glacio-eustasy as has come to light, and there have been sig- tions using these fossil groups in the the driving mechanism for the third-order nificant refinements in time scales, making Triassic include taxonomic standardization, cyclicity can be ruled out. And even though a review and revision of the Triassic sea- rarity of markers, potential diachroniety transfer of water to and from land aquifers level variations timely. The documentation in conodontsʼ first and last appearance, to the ocean as a potential cause is plausible for the revised Triassic sea-level curve, and provinciality among ammonoids. for minor (a few tens of meters) sea-level though still largely from northwestern Since much of the Pangaean landscape was falls, the process seems counter-intuitive and central Europe (western Tethys), now dominated by terrestrial sediments, regional for third-order events for much of the also includes sections further east from correlations often rely on palynology, Triassic. Triassic paleoenvironmental other parts of the Tethys, such as the ostracods and that do not lend scenarios demonstrate a close link between Arabian Platform, , , , themselves to wider correlations with eustasy, climates, and . and Australia. From the boreal latitudes marine records. Ogg et al. (2016) ascribe a

GSA Today, v.28, https://doi.org/10.1130/GSATG381A.1. Copyright 2018, The Geological Society of America. CC-BY-NC.

1Data Repository item 2018390, background and documentation of depositional sequences for the new Triassic sea-level curve, is online at www.geosociety.org/datarepository/2018/. composite error of between 0.2 and 0.59 are similar to the sea-level curve, recording duration = 0.77 m.y.), and expand for the m.y. for the boundaries in the Triassic only a long-duration signal in the Late remainder of the Carnian through Rhaetian depending on the type of data (see also the Triassic (Trotter et al., 2015). This singular interval (average ammonoid zonal duration GSA data repository for further discussion attribute of the Triassic stratigraphy (i.e., = 2.43 m.y.). Using multiple overlapping of time scales [see footnote 1]). the potential of missing marine strati- criteria (i.e., several fossil groups), these graphic record and large time gaps that uncertainties can sometimes be narrowed. LARGE TIME GAPS IN THE shows up in sequence-stratigraphic signal) The long-term sea-level envelope for the RECORD OF THE MIDDLE requires further thought and inquiry. Triassic is similar to those shown in Haq et AND LATE TRIASSIC? al. (1987, 1988) and Hardenbol et al. (1998). Even a cursory look at the most recent REEVALUATION OF THE The original long-term curve for the update of the Triassic time scale (Ogg et al., TRIASSIC SEA-LEVEL CURVE Triassic was based on continental flooding 2016) reveals its extreme lopsidedness: As stated above, the main correlative data and this is still the case, because other while the spans only 5.1 m.y. criteria for the Triassic marine strata are constraints for this envelope, such as mean and the Middle Triassic increases to 9.1 ammonoid and biostratigraphies. of oceanic crust, are not available since m.y., the Late Triassic jumps to a substan- The distribution of Triassic ammonoids almost all of the Triassic age oceanic crust tial span of 35.6 m.y. Some unevenness is to taxa in the boreal latitudes (e.g., British has since been subducted, with the excep- be expected, but this extreme asymmetry is Columbia, Siberia), however, was not the tion of a limited area of the seafloor on also witnessed in the time spans of the same as those in the Tethyan realm, and west of Australia (von stages (ages) and biostratigraphic zones this provinciality poses limitations for direct Rad et al., 1989). Recently van der Meer within the stages, as well the lengths of the correlations. The detailed cross-correlation et al. (2017) have produced independent sequence cycles and corresponding sea- schemes provided by Hardenbol et al. (1998) estimates of the long-term sea level based level events that all increase in duration in that have attempted to tie marine and on Sr-isotope data, which show close the Middle to Late Triassic. terrestrial biostratigraphies from the similarities to the continental flooding If the above apparent chronostratigraphic Tethyan and high latitudes are invaluable curves and to the long-term Triassic curve asymmetry is real, then the large differ- for the longer distance correlations. The presented here, although the interpreted ences in the duration of fossil zones imply correlation chart of these authors also pro- amplitudes differ. The documentation for that evolutionary rates (as measured by vides links to the stratigraphic distribution the short-term (third-order) sea-level events appearance of new species/m.y.) were of other Tethyan fossil groups, such as is based on sequence-stratigraphic informa- relatively rapid in the Early Triassic (thus calcareous nannofossils, dinoflagellates, tion pieced together from several available the availability of a high-resolution biozonal larger foraminifera, ostracods, radiolarians, longer duration sections and augmented by subdivision), declining somewhat in the and spore and pollen, which can be invalu- some shorter-duration records. In addition Middle Triassic, and slowing down to an able in constraining some of the long- to sequence-stratigraphic interpretive extreme thereafter (characterized by a few distance correlations (Hardenbol et al., criteria that are now well established and long-duration ), especially in the 1998, chart number 8). do not require repetition, other features that later Late Triassic. However, the temporal In this reappraisal of the Triassic sea- were particularly helpful in stratigraphic lengths of sequence cycles (based on sedi- level variations, which uses all available interpretations (originally listed in Haq mentary facies shifts) do not have to follow sequence-stratigraphic data published and Schutter, 2008) in the Triassic include the biotic evolutionary trends, and yet they since the last such compilation (Haq and forced-regressive facies, organic-rich facies do. Their long time spans (average of ~5 Al-Qahtani, 2005) as well as older studies, of the condensed sections, transgressive m.y./cycle in the Middle and Late Triassic) was reevaluated before inclusion in the coals, evaporites, exposure-related deposits would imply a built-in bias in the record current synthesis. The documentation for (including incised valley fills, autochtho- expressed as a lack of preserved marine the revised Triassic sea-level curve still nous coals, eolian sandstones, and karst), stratigraphic record. This seems plausible comes largely from low to temperate paleo- and laterite/bauxite deposits. These fea- in a scenario where the long-term trend of latitudes of the Tethys, but also includes tures can often aid in the identification low seastands for the period means fewer its boreal counterpart sections from the of depositional surfaces and tract marine records in favor of more terrestrial Sverdrup Basin, Svalbard, and the Barents boundaries on outcrops and in well logs. sedimentary records. This is exacerbated Sea. As indicated previously for the The earlier syntheses for the Triassic by mostly type-1 sequence boundaries Jurassic (Haq, 2017), the reliance mainly on period (Haq et al., 1987, 1988; Hardenbol (when the base line withdraws beyond the ammonoids and conodont biostratigraphies et al., 1998; Haq and Al-Qahtani, 2005) shelf edges) that may incorporate large for correlations means that the built-in continue to be the basis for the new erosional time gaps. Large temporal uncertainty in the proposed ages of revision presented here. The Triassic cycles lacunae in the stratigraphic record could sequence boundaries is equal to the dura- presented in Haq et al. (1987, 1988) were explain the potentially specious signal that tion of the (or subzone) that is used based on sections from NW Europe (Italy, comes across as slowdown in the biotic to date the boundary. This means that Austria), the Arctic (Svalbard, Bjørnøya evolutionary rates, as well as the dearth of error-bars are relatively small in the Induan in the Barents Sea), and Pakistan (the Salt sequence cycles for the interval in question through interval (average zonal Range). Hardenbol et al. (1998) consider- (i.e., Middle and Late Triassic). An oxygen- duration = 0.34 m.y.), increase to medium ably augmented this Triassic data from isotopic record of the Triassic derived from levels for the Ladinian through earliest the European basins, putting it on better- Tethyan conodont apatite shows trends that Tuvalian interval (average ammonoid zonal defined biostratigraphic footing and identifying 13 additional sequences as well. The base level actually fell just below One clear trend in the Triassic is the The Triassic portion of Haq and pdmsl in the Anisian, reserving this trend overall low seastands of this period. If one Al-Qahtani (2005) was mainly based on in the Fassanian substage of the early were to also include the lowstands on both cycles identified from the Arabian Ladinian when a steady rise is seen that ends of the Triassic, i.e., in the latest Platform. For the current reappraisal, those culminated in the highest sea levels of the Permian (starting ca. 260 Ma) as well as data have been further augmented with Triassic (~50 m above pdmsl) in the the earlier Jurassic (ending ca. 180.5 Ma), third-order cycles from published sources Tuvalian substage of the late Carnian. From it represents an interval of almost 80 m.y., as follows: the Triassic of Northern this peak the trend reverses again to a long- when the sea levels were universally low Germany (Aigner and Bachmann, 1992) term decline in the Lacian substage of the and do not seem to have risen more than and Induan through Ladinian of Black early Norian. Through the Alaunian and 50 m above pdmsl at the highest point (in Forest (Bourquin et al., 2006); Induan much of the Sevatian substages of the late the Carnian). This 80-m.y. period was also through Carnian of Balaton, Hungary Norian, the base level remained steady and an interval when there is no known evi- (Budai and Haas, 1997); the Triassic of very close to pdmsl. At the Norian-Rhaetian dence of large continental glaciations any- Transdanubian Range in Hungary, the boundary the base level dips once again where in the higher latitudes. Such a long Calcareous Alps of Austria and of Germany, just below pdmsl, recovering for a short duration of oceanic withdrawal from the and the Lombardi Basin in Italy (vide Haas time in the mid-Rhaetian and then declin- large landmass of Pangaea seems unique in and Budai, 1999, and references therein; ing rapidly to almost 50 m below pdmsl in the Phanerozoic Earth history and would also see the GSA data repository [see foot- the latest Triassic and earliest Jurassic. have had important repercussions for note 1]); the Triassic of Sverdrup Basin The short-term sea-level curve, superim- global climates and biodiversity (see fur- (Embry, 1997); the Triassic of Norwegian posed on the long-term eustatic curve, is ther discussion in the GSA data repository Barents shelf, Bjørnøya and Svalbard (van based on sequence boundaries that are [see footnote 1]). These could potentially Veen et al., 1992; Glørstad-Clark et al., consistently correlatable in several basins include the presence of large desert areas 2010; Mørk et al., 1989); the Triassic of and widespread salinas in arid regions, are therefore considered widespread. Two Arabian Platform (Sharland et al., 2001, extreme climates, especially in the conti- cycles, one each in the Norian and the 2004; Haq and Al-Qahtani, 2005); the nental interiors, high sea-surface tempera- Rhaetian (TNo2 at 222.5 Ma and TRh1 at Triassic of United Arab Emirates (Maurer tures, relatively flat equator-to-pole gradi- 203.5 Ma), are included tentatively, pending et al., 2008); the Triassic of Spiti, northern ents, and sluggish surface circulation. their confirmation from other areas as India (Bhargava et al., 2004; Krystyn et al., Deeper circulation would be characterized being more widespread. The amplitudes 2005); Induan through mid-Anisian of east- by warm saline bottom waters with inter- of third-order cycles (measures of sea-level ern Yangtze Platform, China (Tong and mittent loss of vertical stratification leading falls in meters) are particularly difficult to Yin, 1998); and the Triassic of Carnarvon to widespread anoxia. Tropical shallow estimate. The estimates of sea-level falls Basin, Australia (Gorter, 1994). It is appar- marine areas during relative highs could be are always relative to the preceding high- ent from this list that the Triassic sea-level sites of carbonate and extensive evaporite variations as documented in the new stand, and their determination criteria can deposition. Biodiversities would decline cycle chart remain mostly centered in include such relative measure as thickness when summer temperatures exceeded a the Tethyan realm (its western boreal and of the system tracks, bio- and lithofacies certain threshold both on land and at sea. its eastern low to temperate latitudes exten- depth assessments, depth of incision of A long period of lowstand and continuous sions) (see the GSA data repository [foot- shelves (in case of type-1 sequences), and high temperatures also mean a deficit of note 1] for the complete documentation partial back-stripping (see Haq, 2014, biologic evolutionary innovations, and evi- of the sequence boundaries of the Tethys for further discussion). In the cycle chart dence gathered by Triassic paleoclimatic realm). presented here (Fig. 1) they are averaged and paleoceanographic studies confirms from stratigraphic estimates in several these paleoenvironmental consequences. RESULTS AND DISCUSSION basins and should be considered best Biodiversity was decimated at the end- The results of the revision of the Triassic guesstimates. They are categorized into Permian event and, after the cycle chart are shown in Figure 1. Since the three groupings of sea-level falls: major Early through Middle Triassic recovery, revised eustatic curve is largely based on (>75 m of fall relative to previous high), declined once again during the long inter- the sections in the low- to mid-latitudes of medium (25–75 m of relative fall), and val of the Late Triassic (these issues are the Tethys Ocean, the biochronological minor (<25 m of relative fall). Most Triassic discussed in the GSA data repository [see scheme that is adopted here (after Ogg et sea-level falls were apparently of medium footnote 1]). The Triassic paleoenviron- al., 2016) is also Tethys-centric. to minor magnitudes. The six falls that mental scenarios demonstrate the close link The long-term eustatic trend shows that exceeded the 75 m amplitude, and are between eustasy, climates, and biodiversity. at the dawn of Triassic sea levels were near therefore considered major, include TIn3 The driving mechanism for the third- or a few meters higher than the present-day at 250 Ma; TAn4 at 242.1 Ma; TLa3 at 238 order cyclicity in the Triassic remains mean sea level (pdmsl) and then rose only Ma; TCa2 at 233.5 Ma; TCa3 at 229 Ma; unidentified, an interval characterized by ~10–20 m in the Induan and . and TNo4 at 209.7 Ma. exceptionally long sedimentary eustatic

Figure 1. Triassic sequences and variations of sea level. Time scale after Ogg et al. (2016). Biozone cross-correlations are after Hardenbol et al. (1998). Sequence boundaries (sea-level fall events) are redesignated following a numbering scheme suggested by Hardenbol et al. (1998), however, the letter T is prefixed to each designation for convenience to make the numbers unique and not to confuse them with similar numbers in other periods. (Two events, in the Norian and Rhaetian [TNo2 and TRh1] are included provisionally, pending documentation of more widespread occurrence.) SEA LEVEL EVENTS LONG-TERM AND MARINE CONODONT AGE TETHYAN (Sequence Boundaries) SHORT-TERM AGE PERIOD STANDARD POLARITY ZONES (Ma) AMMONOIDS [Movement of Shoreline] SEA-LEVEL-CURVES (Ma) STAGE / SUBSTAGE CHRON (GENERAL) LANDWARD BASINWARD 150 100 50 0 m -50 -100 (AGE) Psiloceras planorbis 200.2 JHe2 [JURA.] Psiloceras spelae 201 JHe1 201.4 LT27n- 201.4 TRh3 LT28n C. marshi M. ultima 202 TRh2 SEA LEVEL

V. stuerzenbaumi M. rhaetica 203.5 TRh1 STK"I- M" APPROXIMATE PRESENT-DAY 205 M. posthernsteini s.str. 205 RHAETIAN (Italian GSSP candidate) STK lower S. reticulatus R- M. posthernsteini s.l. zone (Austria GSSP candidate)

LT23n 209.7 TNo4 210 210 M. spinescens M. hernsteini- P. andrusovi LT22n SEVATIAN LT21r S. quinquepunctatus LT21n Long-term E. bidentata curve LT20r LT20n H. macer 215 LT19r 215 ALAUNIAN LT19n M. postera LT18r H. hogarti LT17r- E. spiculata 18n C. bicrenatus M. medionorica 217.3 TNo3 J. magnus LT17n

E. triangularis -

LATE N. hallstattensis 220 LT16r 220 NORIAN

M.paulckei

222.5 TNo2 LT14n- E. quadrata (?) LACIAN 16n

225 225 LT13r

G. jandianus M. communisti 226.5 TNo1

LT13n

LT12r 229 LT12n TCa3 A. spinosus C. pseudodiebeli 230 230 LT11n C. zoae TUVALIAN LT10r T. subbullatus Short-term TRIASSIC M. carpathicus LT10n curve

T. dilleri P.. postinclinata ?- P. noah I.Z. 233.5 TCa2 LT4r A. austriacum

CARNIAN G. tethydis - JULIAN LT3r P. postinclinata 235 T. aonoides 235 LT2n T. aon B diebeli- 236.2 TCa1 CORDEVOLIAN Q polygnathiformis LT1n D. canadensis Budurovignathus F. regoledanus MT13 n. sp. (Kozur) LONGOBARDIAN P. neumayri 238 TLa3 MT11r B mungoensis MT11n P. longobardicum E. gredleri 239.5 TLa2 B. hungaricus 240 P. margitosum 240 FASSANIAN MT9n B. truempyi P.? trammeri trammeri- 240.8 LADINIAN E. curionii TLa1 MT9r N. aequidentata P.? trammeri trammeri- N. secedensis P.alpina MT7n 242.1 TAn4 R. reitzi P. alpina- P.? trammeri ILLYRIAN MT6r K. felsoeoersensis praetrammeri N. mesotriassica

MIDDLE P. trinodosus MT4r- S. binodosus N. constricta 243.5 TAn3 PELSONIAN 5r B. balatonicus P. bifurcata Kocaella MT4n BITHYNIAN Paracrochordiceras (Nev.) P. bulgarica 244.7 TAn2 245 L. caurus (Nev.) (N. germanica and 245 S. mulleri (Nev.) 245.5

ANISIAN TAn1 N. kockeli s.z.) AEGEAN MT3n P. guexi (Nev.) J. welteri MT1-2 N. haugi N.? regalis 246.9 TOl2 ET9r-MT3r Subcolumbites C. timorensis ET8n- Procolumbites SPATHIAN 9n C. gondolelloides C. parisianus T. sosioensis 247.9 TOl1 ET5n- Columbites - Tirolites I. collinsoni 7n G. sinuatum - W. distractus N. pingdingshanensis

KIAN SMITHIAN Owenites B. buurensis-S. milleri B. compressus-F. flemingianus N. waageni OLENE- R. rohilla V. cf. pulchrum N. dieneri Morph 3 250 TIn3 250 DIENERIAN 250 EARLY ET2n F. bhargavai - Kashmiritidae S. kummeli P. rotundatus 250.8 TIn2 G. frequens C. krystyni GRIESBACHIAN P. planidorsatus Isarcicella isarcica IND- UAN ET1n O. tibeticum parvus 251.9 TIn1 251.9 O. woodwardi C. meishanensis O. fissisellatum C. yini 252.6 [PERMIAN] H. changxingense PCh2 253.5 PCh1 Bilal U. Haq (2018) MAJOR CYCLE BOUNDARY MEDIUM OR MINOR CYCLE BOUNDARY POTENTIAL CYCLE BD. (NOT YET CONFIRMED) periodicities in the Middle and Late effects that try to explain long-wavelength topography: Lithosphere, v. 5, p. 189–210, https:// Triassic (~5-m.y./cycle on average for third- and long-term tectonic warping (see, e.g., doi.org/10.1130/L245.1. order sequences) and no evidence of wide- Föllmi, K., 2012, life, climate and Gurnis, 1993; Flament et al., 2013). On anoxia: Cretaceous Research, v. 35, p. 230–257, spread glaciation. However, the relatively these longer scales subducting slabs under- https://doi.org/10.1016/j.cretres.2011.12.005. moderate variations in third-order sea lev- neath continents dramatically influence Glørstad-Clark, E., Faleide J-I., Lunschien, B. and els make it tempting to consider the surface topography that in turn could drive Nystuen, J., 2010, Triassic sequence stratigraphy possibility of changes driven by the transfer local eurybathic and paleogeography of the western Barents Sea: Marine and Petroleum Geology, v. 27, of water to and from land aquifers as a sea-level changes. Thus, dynamic topogra- p. 1448–1475, https://doi.org/10.1016/j.marpetgeo potential cause. Since the early suggestion phy-driven variations seem to be a promis- .2010.02.008. by Hay and Leslie (1990) and Jacobs and ing avenue to follow to explain the rela- Gorter, J.D., 1994, Triassic sequence stratigraphy Sahagian (1993) there has been consider- tively small amplitude but long duration of the Carnarvon Basin, Western Australia able recent interest in this mechanism as a highs and lows (within the range of –50 m in Purcell, P.G., and Purcell, R.R., eds., The Sedimentary Basins of Western Australia: potential cause for eustatic changes (e.g., to +50 m of pdmsl) of the long-term Perth, Proceedings of the Petroleum Exploration Föllmi, 2012; Wagreich et al., 2014; eustatic sea level in the Triassic. So far such Society Australia Symposium p. 397–413. Wendler and Wendler, 2016; Sames et al., modeling for the Triassic Gurnis, M., 1993, Phanerozoic marine inundation 2016). Nevertheless, this process is more and its margins has not been attempted and of continents driven by dynamic topography attuned to explaining modest (20–30 m) above subducting slabs: Nature, v. 364, p. 589– is obviously an area of important future 593, https://doi.org/10.1038/364589a0. input/sequestration of water from/to land investigation. Haas, J., and Budai, T., 1999, Triassic sequence groundwater aquifers (and to a much lesser stratigraphy of the Transdanubian Range extent, the lakes that contribute only a ACKNOWLEDGMENTS (Hungary): Geologica Carpathica, v. 50, no. 6, p. 459–475. minute, almost unmeasurable, amount to The author is indebted to professors James Ogg, Hallam, A., and Wignall, P.B., 1997, Mass the total) to the ocean on Milankovitch William Hay, Jerry Dickens, and an anonymous extinctions and their aftermath: New York, reviewer for detailed reviews of the paper and time scales (Hay and Leslie, 1990). In the Oxford University Press, 330 p. many useful suggestions that improved the quality Triassic the process seems counterintuitive Haq, B.U., 2014, Cretaceous eustasy revisited: of the paper. Christopher Scotese provided the as very dry periods on land coincide with Global and Planetary Change, v. 113, p. 44–58, reconstructions on which Figure S1 is based. https://doi.org/10.1016/j.gloplacha.2013.12.007. lowstands of sea level when presumably Alexandre Lethier (Sorbonne, ISTEP) assiduously continental interiors would tend toward Haq, B.U., 2017, Jurassic sea level variations: A drafted the Triassic cycle chart presented in this reappraisal: GSA Today, v. 28, no. 1, doi:10.1130/ depleted aquifers (and also lack large paper and the figures in the GSA data repository GSATG359A.1. lakes). The reverse also seems to be the that accompanies the paper. 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