The Sedimentary Record Investigating the Paleoecological Consequences of Supercontinent Breakup: Sponges Clean Up in the Early Jurassic

Frank A. Corsetti1, Kathleen A. Ritterbush2, David J. Bottjer1, Sarah E. Greene3, Yadira Ibarra4, Joyce A. Yager1, A. Joshua West1, William M. Berelson1, Silvia Rosas5, Thorsten W. Becker1, Naomi M. Levine1, Sean J. Loyd6, Rowan C. Martindale7, Victoria A. Petryshyn8, Nathan R. Carroll1, Elizabeth Petsios1, Olivia Piazza1, Carlie Pietsch1, Jessica L. Stellmann1, Jeffrey R. Thompson1, Kirstin A. Washington1, Dylan T. Wilmeth1 1 Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089 2 Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637 3 School of Geographical Sciences, University of Bristol, University Road, Clifton, Bristol BS8 1SS, United Kingdom 4 Department of Earth System Science, Stanford University, Stanford, CA 94305 5 Ingeniería de Minas e Ingeniería Geológica, Pontificia Universidad Católica del Perú, Lima, Peru 6 Department of Geological Sciences, California State University, Fullerton, CA 92831 7 Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712 8 Earth, Planetary and Space Sciences Department, University of California, Los Angeles, CA 90095

supercontinent Pangea and the emplacement of the Central ABSTRACT Atlantic Magmatic Province (CAMP), one of the largest The continued release of fossil fuel carbon into the atmosphere igneous provinces in Earth’s history (e.g., Marzoli et al., 1999; today means it is imperative to understand Earth system McHone, 2002; Nomade et al., 2007) (Figure 1). Estimates response to CO rise, and the geologic record offers unique 2 of eruption rates vary, but CO2 input could have been on the opportunities to investigate such behavior. Stomatal and order of ~13.2 Gt/CO2 per year, rivaling modern input rates paleosol proxies demonstrate a large change in atmospheric (~36 Gt/CO2 per year) (e.g., Schaller et al., 2011, 2012).

pCO2 across the Triassic-Jurassic (T-J) transition, concomitant The iconic Palisades Sill overlooking the Hudson River is a with the eruption and emplacement of the Central Atlantic classic example of CAMP magmatism (e.g., Blackburn et al., Magmatic Province (CAMP) and the splitting of Pangea. As one 2013). Via some estimates (e.g., Marzoli et al., 1999; Olsen, of the “big 5” mass extinctions—when the so-called modern 1999; McHone, 2002), CAMP lavas would have covered fauna was particularly hard hit—we know the biosphere was the conterminous United States with ~400 m of basalt (in severely affected during this time, but the details are relatively other words, it was big). The rapid addition of CO2 to the poorly understood, particularly with respect to an Earth system atmosphere-ocean system makes the T-J interval a candidate perspective. As part of the NSF Earth Life Transitions initiative, for ocean acidification in deep time (Hautmann et al., 2008; our team has targeted the T-J for integrative investigation to Greene et al., 2012; Martindale et al., 2012). And, like many explore, among other things, alternative ecological states that mass extinctions, the organic carbon cycle appears perturbed may exist in the aftermath of mass extinctions. The initial across the boundary, with a negative carbon isotope excursion findings reveal a global “sponge takeover” in the Early Jurassic recorded in many sections (e.g., Ward et al., 2001; Guex et al., following the extinction that lasted nearly 2 million years. The 2004; Hesselbo et al., 2004; Williford et al., 2007) sponge takeover may be linked to an unusual confluence of The T-J interval includes one of the “big 5” mass factors, including potential ocean acidification and intense silicate extinctions, a critical transition for life on Earth (e.g., Raup weathering following the emplacement of CAMP. and Sepkoski, 1982) (Figure 1). Notably, representatives of the fauna that inhabit today’s seas (the so-called modern fauna sensu Sepkoski, 1981), and animals living in reef and INTRODUCTION carbonate-dominated environments were preferentially The Triassic-Jurassic (T-J) interval represents a slice of deep negatively affected by the end Triassic mass extinction (Alroy, time when the Earth experienced a rapid rise in pCO (e.g., 2 2010; Kiessling and Simpson, 2011; Kiessling et al., 2007). McElwain et al., 1999; Beerling and Berner, 2002; Berner Furthermore, it was the first major extinction experienced by and Beerling, 2007; Steinthorsdottir et al., 2012; Schaller scleractinian corals (Kiessling and Simpson, 2011; Kiessling et et al., 2011, 2012) resulting from the initial splitting of the al., 2007) (Figure 1). Thus, the end-Triassic mass extinction is

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Figure 1: Summary of features associated with the T-J interval. A) Paleogeographic map of the T-J, with key localities and the hypothesized extent of CAMP marked (modified from Greene et al., 2012). B) Generic diversity of the Cambrian, Paleozoic, and Modern Faunas, highlighting that the T-J extinction was particularly devastating to the Modern Fauna (Alroy 2010). C) Summary of pCO2 levels across the T-J from stomatal proxies (green) and pedogenic proxies (brown) (symbols for stomatal and pedogenic proxies represent individual localities as discussed in Martindale et al., 2012). D) Extinction rate across the T-J interval, highlighting preferential extinction of fauna associated with carbonate environments and reefs (Kiessling and Simpson, 2011; Kiessling et al., 2007).

especially relevant for understanding the some preliminary results from two of Ward et al., 2007) and paleontological

present-day impact of rising CO2 levels our major field areas—Nevada and research (e.g., Laws 1982; Taylor et al., on the marine biosphere (Figure 1). The Peru—to highlight the concept of an 1983) set the stage for our studies. T-J interval, as used here, refers to the unexpected “alternate ecological state” in The uppermost Triassic strata of lead up to the extinction in the latest the aftermath of extinction. the Mount Hyatt Member of the Norian and Rhaetian stages (the last Gabbs Formation represent a typical, two stages of the Triassic, respectively) UNEXPECTED POST- prolific Late Triassic carbonate through the Hettangian and early EXTINCTION ECOLOGY: ramp assemblage, including massive Sinemurian Stages (the first two stages SPONGES CLEAN UP IN fossiliferous wackestones and thin- of the Jurassic, respectively), where the THE EARLY JURASSIC OF bedded mudstones (e.g., Laws 1982). extinction event horizon itself is in the NEVADA The shift to siliciclastic-dominated latest Triassic (Rhaetian Stage). In west central Nevada, the Gabbs sedimentation in the overlying Muller Typically, the biotic response to mass and Sunrise Formations of the Gabbs Canyon Member of the Gabbs extinction events is treated as a “numbers Valley Range comprise an excellent, Formation represents a collapse of the game”, where the loss of standing well-exposed Triassic – Jurassic shallow vibrant carbonate system in association diversity is the focus, followed by some shelf depositional sequence (Figures 2 with the mass extinction (e.g., Lucas et “recovery” in the number of taxa in and 3). It was once in the running to al., 2007). The shales, siltstones, and the aftermath of the extinction. But become the global stratotype section fine sandstones of the Muller Canyon what defines recovery? Simply focusing and point (GSSP) (e.g., Lucas et al., Member contain the Triassic/Jurassic on a return to pre-extinction levels 2007). The strata were deposited in a boundary. The lower to middle Muller of diversity deemphasizes potentially basin between the Sierran arc and the Canyon Member has been previously interesting and important alternate North American continent in eastern interpreted to represent a regression ecological states (e.g., Hull and Darroch Panthalassa (Figure 1) (e.g., Stewart, (Laws, 1982), a transgression (Hallam 2013). As such, unraveling the marine 1980). Comprehensive mapping and Wignall, 2000), or a transgression- paleoecology in the aftermath of the (e.g., Muller and Ferguson 1939), regression couplet (Schoene et al., extinction has been a major focus of biostratigraphy (e.g., Guex et al., 2004), 2010). Recent macro-, meso-, and our recent studies. Here, we present chemostratigraphy (Guex et al., 2004; microscale facies analysis demonstrate

June 2015 | 5 The Sedimentary Record very little/subtle sedimentary change the eventual return of carbonate ramp means recovered to a pre-extinction throughout the lower two thirds of the deposition (e.g., Lucas et al., 2007; state. Rather, macroscopic benthic Muller Canyon Member. Laminated Ritterbush et al., 2014). fossils remain rare and are not detected siltstones and rare very fine sandstones After the last occurrence of the in thin section in most of the Jurassic with low amplitude hummocky cross uppermost Triassic ammonite C. Muller Canyon Member strata (~10 stratification indicate a position below crickmayi in the Muller Canyon m, which we term the Depauperate fair-weather wave base/near storm Member, shelly benthic fossil content Zone in Figures 2 and 3) (Ritterbush wave base on the middle to inner shelf, drops dramatically, to essentially et al., 2014). While a slightly greater similar to the underlying carbonate- undetectable levels, marking the abundance of ammonoids is noted in dominated Mount Hyatt Member. extinction event (Figures 2 and 3). the Depauperate Zone, benthic fossils Rather than recording a significant This interval is also characterized by are limited to isolated occurrences of depth change, it appears that metazoan- the initial negative carbon isotope rare Modiolus mussel clusters, small dominated carbonates are simply not excursion seen worldwide (Figures 2 Agerclamys scallops, preserved primarily present in the Muller Canyon Member. and 3), and the subsequent 7 meters as casts without substantial shell Beds gradually increase in thickness in are considered the Extinction Interval material (see also Taylor et al., 1983; the upper Muller Canyon Member, (Figure 3). The base of the Jurassic Hallam and Wignall, 2000; Ward et al., until their transition to thin-bedded is defined by the first appearance of 2007; Taylor et al., 2007), and rare 4-6 silty carbonates of the overlying the ammonite P. spelae (Guex et al., cm-deep Helminthoides or individual carbonate-rich Sunrise Formation and 2004), but the ecosystem had by no Rhizocorallium burrows.

Figure 2: Photograph of Ferguson Hill, Muller Canyon, Nevada. Carbon isotope profile from Ward et al. (2007) (isotopic scale is given in Fig. 3), corrected for the presence of a fault. Note paleobiologist, for scale.

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Figure 3: A) Summary of features from the T-J interval in Nevada (ammonite biostratigraphy from Guex et al, 2004; ash date from Schoene et al., 2010; approximate ages of key ammonites from Guex et al., 2012; δ13C record, black data points from Ward et al., 2007; red data points, 13 this study). Our measured section is consistent with Guex et al (2004). Our δ Corganic data is comparable to that of Ward et al. (2007), as we heated our samples to 70°C during acidification to remove all carbonate, including refractory phases like siderite and dolomite. Benthic paleoecology and microfacies modified from Ritterbush et al., 2014 and references therein). B) Corals, gastropods, and other shelly fauna from the Sinemurian of Nevada, near New York Canyon, representing the recovery of the carbonate fauna up-section from the extinction. C) In situ body fossils of sponges, near New York Canyon, Nevada. D) Photomicrograph of spiculite from the “Sponge Takeover”, Muller Canyon, Nevada. Arrows point to spicule examples.

The main lower Jurassic ammonite remain extremely depauperate, both next via spicule-filled burrows, and diversification occurs near the base in abundance and diversity, and the finally via pure spiculite including of the Ferguson Hill Member of the return of carbonate bedding is not in situ siliceous sponges (Ritterbush Sunrise Formation, indicating a major accompanied by a dramatic increase et al., 2014) (Figure 3 C, D). For radiation of pelagic forms (e.g., Guex et in macroscopic shell content as might the first time since the extinction al., 2004), and a more robust recovery be expected, a finding paralleled at the horizon, metazoans become a major in the pelagic realm. Interestingly, microscopic level (Ritterbush et al., constituent in the sedimentary record, via correlation with radiometrically- 2014). potentially indicating a significant dated successions (e.g., Peru; Guex Unexpectedly, the next 40 meters recovery in the benthic realm. But et al., 2012), the radiation is nearly of strata, representing the remaining rather than carbonate producers, it coincident with the cessation of CAMP Hettangian Stage and the lower part is siliceous demosponges that take volcanism (Blackburn et al., 2013); that of the Sinemurian Stage, are replete over the shelf, reflecting an interesting is, the start of a more robust recovery with sponge spicules (Ritterbush et alternative-ecosystem-state in the did not occur until CAMP volcanism al., 2014), first via 20 m of abundant aftermath of extinction. Styles (simple terminated. Shelly faunas, however, transported siliceous sponge spicules, spicules), dichotriaenes (complex

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Figure 4: A) Field image of the T-J interval, Pucará Basin, Peru (Malpaso Section, Ritterbush et al., 2015). B) Photomicrograph of spiculite from the Aramachay Formation, Morococha section, Peru; arrows point to spicule examples.

spicules), and desmid spicules (highly Aramachay Formation (Figure 4) appear on ecological time scales. The full two mineralized spicules) of astrophorid nearly identical to their counterparts million year occupation, however, is a demosponges dominate the spiculites. in Nevada. The Hettangian sponge geologic-scale event, and most models Abundant carbonate storm beds in phenomenon extends throughout of ocean acidification, which would the cherty interval support a middle Europe (Austria, France), as well as suppress the carbonate producers, last shelf depositional environment and Morocco (e.g., Delecat et al., 2010; perhaps tens of thousands of years, not blanket in situ sponges in some cases. Neuweiler et al., 2001). Many of the millions (e.g., Hönisch et al., 2012); These sedimentological observations European localities represent deeper mere ecological patterns do not offer indicate that carbonate sedimentation paleoenvironments, so the siliceous a satisfying explanation without input was present, but sponges—silica, not sponge accumulations may not have from the broader environment. carbonate—constituted the major been considered unusual, given the Silica constitutes a major nutrient for metazoan contribution to sediments. modern distribution of siliceous sponges silica sponges, and may hold some of The remaining strata record an abrupt in the deep whereas they are more the answers for the duration and timing shift to carbonate-dominated bioclastic remarkable in the stratigraphically of the T-J sponge event. The rifting wackestones, packstones, and ooid-rich expanded shallow water occurrences in of Pangea and eruption of CAMP is grainstones, heralding the return of Nevada and Peru. likely to have affected silica supply by a robust carbonate ramp, including a increasing weathering fluxes, the primary return of corals, bivalves, and gastropods WHY SPONGES? silica source to the oceans. Increases

(Figure 3B), marking the next step in During recoveries from global mass in atmospheric pCO2 would have the recovery of the ecosystem from the extinctions, ecological complexity is intensified silicate weathering delivering end-Triassic extinction. expected to expand through a succession additional silica to the oceans (e.g., of trophic levels (e.g., Sole et al., 2002), Berner and Beerling, 2007; Schaller A GLOBAL SPONGE but novel scenarios may emerge via et al., 2011). Presence of the CAMP TAKEOVER? chance ecological or environmental basalts should have further increased Sponge hegemony characterizes the opportunities (e.g., Hull and Darroch, weathering fluxes of silica; weathering is early Jurassic of Nevada, but is the 2013). We hypothesize that the T-J faster on fresh rock, and is observed to takeover a local phenomenon or does “sponge takeover” resulted from the be five times faster on basalts compared it have global significance? Previous unique confluence of ecological and to granites (West et al., 2011). publications hinted that sponge environmental circumstances in the The types of spicules produced deposits existed in the Pucará Group, aftermath of the end-Triassic mass by sponges, and the rates of silica Peru (Szekely and Grose, 1972; Rosas extinction. Ecologically, the decimation uptake, depend on silica concentration et al., 2007). Our recent work with of previously dominant calcifiers during (Maldonado et al., 1999; Reincke collaborator Silvia Rosas demonstrates the Triassic-Jurassic transition likely and Berthel, 1997) and may provide that, like Nevada, shallow water facies eliminated incumbency challenges further evidence for enhanced silica of the T-J Aramachay Formation, to sponges settling across the shelf. supply during the sponge takeover. Pucará Group, Peru, record abundant In modern reef settings, it is not Desma spicules, which are more robust spiculites, spiculite filled burrows, and uncommon for sponges to initially and can interlock, are ubiquitous in in situ sponge body fossils (Ritterbush colonize areas vacated by corals, only the Nevada and Peru Early Jurassic et al., 2015). In fact, some strata of the to have the corals retake the real estate deposits (Ritterbush et al., 2015;

8 | June 2015 The Sedimentary Record 2015). Desmas are produced by system. Nonetheless, though we do REFERENCES a broad variety of sponges if silica not expect a sponge takeover, the T-J ALROY, J., 2010b, The shifting balance of diversity concentration is sufficient (e.g., 30-100 example might indicate the ramifications among major marine animal groups: Science 329, m; Maldonado et al., 1999), and thus of providing an abundant supply of a 1191–1194. m BEERLING, D.J., BERNER, R.A., 2002. may constitute evidence for elevated limiting nutrient to diatoms as a result Biogeochemical constraints on the Triassic- silica concentrations during the sponge of increased weathering in a warmer Jurassic boundary carbon cycle event. Global takeover. A box model investigating the climate must be considered as a potential Biogeochemical Cycles 16, 10–1–10–13. T-J silica budget provided in Ritterbush marine consequence of anthropogenic BERNER, R.A., BEERLING, D.J., 2007. Volcanic degassing necessary to produce a et al. (2015) is also consistent with the CO2 release, in addition to the aforementioned scenario. Thus, the deleterious effects of increased CO CaCO3 undersaturated ocean at the p 2 Triassic–Jurassic boundary. Palaeogeography, sponge event likely originated from a on coral reefs. More generally, the T-J Palaeoclimatology, Palaeoecology 244, 368–373. cascade of events following the rifting sponge takeover represents an excellent DELECAT, S., ARP, G., REITNER, J., 2011. of Pangea and eruption of CAMP: example of “alternative ecological states” Aftermath of the Triassic–Jurassic Boundary Crisis: Spiculite Formation on Drowned CAMP CO2 initially caused ocean perhaps not predicted via the typical acidification, suppressing the incumbent actualistic view of the Earth system, and Triassic Steinplatte Reef-Slope by Communities coral reefs, then, on a longer time scale, a manifestation of the law of unintended of Hexactinellid Sponges (Northern Calcareous Alps, Austria). in Advances in Stromatolite silicate weathering provided the limiting consequences. Geobiology, Joachim Reitner, Nadia-Valérie nutrient, silica, that allowed the sponges Quéric, Gernot Arp, eds., Springer-Verlag, to take hold for upwards of 2 million ACKNOWLEDGEMENTS p. 355–390. years. The coincidence of the ecological This research was funded by the NSF GREENE, S.E., MARTINDALE, R.C., and geochemical circumstances Earth-Life Transitions (ELT) program RITTERBUSH, K.A., BOTTJER, D.J., demonstrates why such an event is (EAR-1338329). Additional sources CORSETTI, F.A., BERELSON, W.M., 2012. Recognising ocean acidification in deep time: An best investigated from an Earth-Life of funding include NASA Exobiology evaluation of the evidence for acidification across Transitions perspective. (NNX10AQ44G), NSF EAGER the Triassic-Jurassic boundary. Earth Science (1017536), UK NERC grant NE/ Reviews 113, 72–93. FROM THE T-J H023852/1s, the American Museum GUEX, J., BARTOLINI, A., ATUDOREI, V., LOOKING FORWARD of Natural History, the American TAYLOR, D., 2004. High-resolution ammonite Our preliminary results from the T-J Philosophical Society, The Geological and carbon isotope stratigraphy across the Triassic–Jurassic boundary at New York Canyon suggest that, with increased pCO2 in Society of America, SEPM Society for (Nevada). Earth and Planetary Science Letters the atmosphere, the potential for ocean Sedimentary Geology, the American 225, 29–41. acidification exists, silicate weathering Association of Petroleum Geologists, GUEX, J., SCHOENE, B., BARTOLINI, A., should increase, and the flux of silica Aera Energy LLC, the USC Wrigley SPANGENBERG, J., SCHALTEGGER, U., and alkalinity to the oceans should Institute for Environmental Studies and O’DOGHERTY, L., TAYLOR, D., increase. Will we be faced with another the Sonosky Family, as well as material BUCHER, H., ATUDOREI, V., 2012. Geochronological constraints on post- sponge takeover in our future? Ocean assistance from the Pan American Silver extinction recovery of the ammonoids and acidification is measureable today as Company. Assistance in the field was carbon cycle perturbations during the Early Jurassic. Palaeogeography, Palaeoclimatology, CO2 builds in the atmosphere and provided by C. Astorga, J. Zarate, V. equilibrates with the ocean—the lesson Cajachagua, A. Allam, S. Mata, B. Palaeoecology 346-347, 1–11. from the T-J regarding the possible Haravich, M. Gawey, L. Tackett and HALLAM, A. AND WIGNALL, P. B., 2000, effects on coral reefs (that is, they could M. Lewis, as well as staff of the Pan Facies changes across the Triassic-Jurassic boundary in Nevada, USA. Journal of the crash) should be heeded. However, we American Silver Company and Volcan Geological Society London 157, 49-54. suspect the Earth today is not headed for Mining Co. Laboratory assistance HAUTMANN, M., BENTON, M.J., another sponge event, for several obvious was provided by Nick Rollins and TOMAŠOVÝCH, A., 2008. Catastrophic reasons. The silica cycle is different Miguel Rincon. Thanks to J. Guex, ocean acidification at theTriassic-Jurassic today, predominantly controlled by W. Kiessling, A. Piscera, G. Stanley, D. boundary. Neues Jahrbuch für Geologie und diatom abundance and distribution, Kidder, M. Foote, L. Tackett, P. Hull, Paläontologie - Abhandlungen 249, 119–127. HESSELBO, S.P., ROBINSON, S.A., versus the T-J interval, which preceded and M. Schaller for comments and SURLYK, F., 2004. Sea-level change and facies the origination of diatoms. Also, CAMP discussion. development across potential Triassic–Jurassic would have provided an abundance boundary horizons, SW Britain. Journal of the of fresh basalt ripe for weathering, a Geological Society 161, 365–379. situation not present in today’s Earth

June 2015 | 9 The Sedimentary Record HÖNISCH, B., RIDGWELL, A., SCHMIDT, MCELWAIN, J., BEERLING, D., WOODWARD, SEPKOSKI, J.J., JR, 1981. A factor analytic D.N., THOMAS, E., GIBBS, S.J., F., 1999. Fossil plants and global warming at the description of the Phanerozoic marine fossil SLUIJS, A., ZEEBE, R., KUMP, L., Triassic-Jurassic boundary. Science 285, record. Paleobiology 1, 36–53. MARTINDALE, R.C., GREENE, S.E., 1386–1390. SOLE, R.V., MONTOYA, J.M., ERWIN, D.H., KIESSLING, W., RIES, J., ZACHOS, J.C., MCHONE, J.G., 2003. Volatile emissions from 2002. Recovery after mass extinction: ROYER, D.L., BARKER, S., MARCHITTO Central Atlantic Magmatic Province Basalts: evolutionary assembly in large-scale biosphere JR., T.M., MOYER, R., PELEJERO, C., Mass assumptions and environmental dynamics. Philosophical Transactions of the Royal ZIVERI, P., FOSTER, G.L., WILLIAMS, consequences, in Geophysical Monograph Society B: Biological Sciences 357, 697–707. B., 2012. The Geological Record of Ocean Series, Geophysical Monograph Series. American STEINTHORSDOTTIR, M., WOODWARD, Acidification. Science 335, 1058–1063. Geophysical Union, Washington, D. C., F.I., SURLYK, F., MCELWAIN, J.C., 2012. HULL, P.M., DARROCH, S., 2013. Mass pp. 241–254. Deep-time evidence of a link between elevated

extinctions and the structure and function of NEUWEILER, F., MEHDI, M., WILMSEN, M., CO2 concentrations and perturbations in the ecosystems. in Andrew M. Bush, Sara B. 2001. Facies of Liassic Sponge Mounds, Central hydrological cycle via drop in plant transpiration. Pruss, and Jonathan L. Payne (eds.) Ecosystem High Atlas, Morocco. Facies 44, 36–41. Geology 40, 815–818. Paleobiology and Geobiology, The Paleontological NOMADE, S., KNIGHT, K., BEUTEL, E., STEWART, J.H., 1980, Geology of Nevada. Nevada Society Papers 19, 1-42. RENNE, P., VÉRATI, C., FÉRAUD, G., Bureau of Mines and Geology, Special KIESSLING, W., ABERHAN, M., BRENNEIS, MARZOLI, A., YOUBI, N., BERTRAND, H., Publication 4, 1-136. B., WAGNER, P.J., 2007. Extinction trajectories 2007. Chronology of the Central Atlantic SZEKELY, T.S., GROSE, L.T., 1972. Stratigraphy of benthic organisms across the Triassic-Jurassic Magmatic Province: Implications for the Central of the Carbonate, Black Shale, and Phosphate of boundary. Palaeogeography, Palaeoclimatology, Atlantic rifting processes and the Triassic–Jurassic the Pucara Group (Upper Triassic--Lower Palaeoecology 244, 201–222. biotic crisis. Palaeogeography, Palaeoclimatology, Jurassic), Central Andes, Peru. Geological Society KIESSLING, W., SIMPSON, C., 2011. On the Palaeoecology 244, 326–344. of America Bulletin 83, 407–428. potential for ocean acidification to be a general RAUP, D.M., SEPKOSKI, J.J., JR, 1982. Mass TAYLOR, D.G., SMITH, P.L., LAWS, R.A., cause of ancient reef crises. Global Change extinctions in the marine fossil record. GUEX, J., 1983. The stratigraphy and biofacies Biology 17, 56–67. Science 215, 1501–1503. trends of the Lower Mesozoic Gabbs and Sunrise KUERSCHNER, W.M., BONIS, N.R., REINCKE, T., BARTHEL, D., 1997. Silica uptake formations, west-central Nevada. Canadian Journal KRYSTYN, L., 2007. Carbon-isotope kinetics of Halichondria panicea in Kiel Bight. of Earth Sciences 20, 1598–1608. stratigraphy and palynostratigraphy of the Marine Biology 129, 591–593. WARD, P.D., GARRISON, G.H., WILLIFORD, Triassic-Jurassic transition in the Tiefengraben RITTERBUSH, K.A., BOTTJER, D.J., K.H., KRING, D.A., GOODWIN, D., section - Northern Calcareous Alps (Austria). CORSETTI, F.A., ROSAS, S., 2014. New BEATTIE, M.J., MCROBERTS, C.A., 2007. The Palaeogeography, Palaeoclimatology, evidence on the role of siliceous sponges in organic carbon isotopic and paleontological record Palaeoecology 244, 257–280. ecology and sedimentary facies development in across the Triassic–Jurassic boundary at LAWS, R.A., 1982. Late Triassic depositional eastern Panthalassa following the Triassic-Jurassic the candidate GSSP section at Ferguson Hill, environments and molluscan associations mass extinction. Palaios 29, 652–668. Muller Canyon, Nevada, USA. Palaeogeography, from west-central Nevada. Palaeogeography, RITTERBUSH, K.A., ROSAS, S., CORSETTI, Palaeoclimatology, Palaeoecology 244, 281–289. Palaeoclimatology, Palaeoecology 37, 131–148. F.A., BOTTJER, D.J., WEST, A.J., 2015. WARD, P.D., HAGGART, J.W., CARTER, E.S., LUCAS, S.G., TAYLOR, D.G., GUEX, J., Andean sponges reveal long-term benthic WILBUR, D., TIPPER, H.W., EVANS, T., 2001. TANNER, L.H., KRAINER, K., 2007. The ecosystem shifts following the end-Triassic mass Sudden productivity collapse associated with the Proposed Global Stratotype Section and Point extinction. Palaeogeography, Palaeoclimatology, Triassic-Jurassic boundary mass extinction. Science for the base of the Jurassic system in the New Palaeoecology 420, 193–209. 292, 1148–1151. York Canyon Area, Nevada, USA. Triassic of the ROSAS, S., FONTBOTE, L., TANKARD, A., WEST, A.J., BURTON, K., JAMES, R., VON American West, New Mexico Museum of Natural 2007. Tectonic evolution and paleogeography of STRANDMANN, P.P., BICKLE, M., GALY, History and Science Bulletin 40, 139–161. the Mesozoic Pucará Basin, central Peru. Journal A. 2011. Chemical weathering at La Selva Preserve, MALDONADO, M., CARMONA, M.C., of South American Earth Sciences 24, 1–24. Costa Rica, and implications for the role of erosion URIZ, M.J., CRUZANDO, A., 1999. Decline in SCHALLER, M.F., WRIGHT, J.D., KENT, D.V., and material supply in determining weathering

Mesozoic reef-building sponges explained by 2011. Atmospheric pCO2 Perturbations rates of volcanic rocks. Abstract. Ninth silicon limitation. Nature 401, 785–788. Associated with the Central Atlantic Magmatic International Symposium on Geochemistry of the MARTINDALE, R.C., BERELSON, W.M, Province. Science 331, 1404–1409. Earth’s Surface, Boulder, CO. CORSETTI, F.A., BOTTJER, D.J., WEST, SCHALLER, M.F., WRIGHT, J.D., KENT, D.V., WILLIFORD, K.H., WARD, P.D., GARRISON, A.J., 2012, Constraining carbonate chemistry at OLSEN, P.E., 2012. Rapid emplacement of the G.H., BUICK, R., 2007. An extended organic a potential ocean acidification event (the Triassic– Central Atlantic Magmatic Province as a net sink carbon-isotope record across the Triassic–

Jurassic boundary) using the presence of corals for CO2. Earth and Planetary Science Letters Jurassic boundary in the Queen Charlotte and coral reefs in the fossil record, 323-324, 27–39. Islands, British Columbia, Canada. Palaeogeography, Palaeoclimatology, SCHOENE, B., GUEX, J., BARTOLINI, A., Palaeogeography, Palaeoclimatology, Palaeoecology Palaeoecology 350, 114-123. SCHALTEGGER, U., BLACKBURN, T.J., 244, 290–296. MARZOLI, A., RENNE, P.R., PICCIRILLO, E.M., 2010. Correlating the end-Triassic mass ERNESTO, M., 1999. Extensive 200-million- extinction and flood basalt olcanismv at the year-old continental flood basalts of the Central 100 ka level. Geology 38, 387–390. Accepted June 2015 Atlantic Magmatic Province. Science 284, 616-618.

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