PHSC 11000 L20 Paleozoic Events & Mass Extinctions PDF

Environmental History of the Earth Lecture 20: Paleozoic Events and Mass Extinctions PHSC 11000 Spring 2023 These notes summarize the pertinent points of the lecture. You are encouraged to supplement these notes with your own notes from the lecture. Many of the points touched upon here will be fur...

Environmental History of the Earth Lecture 20: Paleozoic Events and Mass Extinctions PHSC 11000 Spring 2023 These notes summarize the pertinent points of the lecture. You are encouraged to supplement these notes with your own notes from the lecture. Many of the points touched upon here will be further discussed during other lectures and/or labs. Paleozoic Era • Paleozoic Era opened with an evolutionary bang (Cambrian Radiation; see Lecture 17). This Lecture Covers… • Key environmental and evolutionary events in the post-Cambrian Paleozoic. • Climate. • Sea level. • Paleogeography. • Evolutionary events. • Mass extinctions. ORDOVICIAN PERIOD (485 to 444 m.y.a.) Ordovician Climate and Sea Level • Climate was hot and sea level generally continued to rise during the early and middle Ordovician. Ordovician Paleogeography • Vast epicontinental seas throughout much of Ordovician. • Highest sea level of entire Phanerozoic during mid- to late Ordovician. • Iapetus Ocean narrowed as Rheic Ocean widened. • Microcontinents such as Avalonia docked with Laurentia and Baltica. • Start of Taconic Orogeny. • Altered oceanic circulation. Ordovician Radiation • Vast expanses of epicontinental and shelf seas, plus changes in paleogeography, resulted in “Ordovician Radiation” of animals. • Dramatic diversification of animal lineages that had originated during Cambrian Radiation. 1 Number of families of animals living in marine environments through the Phanerozoic. From Sepkoski (1981). Ordovician Radiation • Key elements of the Ordovician Radiation include: • Origin of tabulate and rugose corals (bioherm builders). • Diversification of filter-feeding benthic animals (brachiopods, crinoids, bryozoans, etc.). • Diversification of fish. Ordovician Landscape • Small, moss-like green plants in and around edges of watery habitats. • Land areas away from water still barren of vegetation; drab. Ordovician Sea Level and Climate • Major glaciation during Late Ordovician. • Tropical surface ocean temperatures fell by up to 10C°. • Sea level fell by 50 to 100 meters. 2 End Ordovician Glaciation • Glaciation centered on Northern Gondwana, which sat over South Pole. • Trigger(s) for glaciation still uncertain. • Paleogeography? • Continental weathering and CO drawdown? • Orbital parameters? • Main glaciation spanned about 1 million years. • Onset and waning of glaciation each coincide with pulses of extinction. 2 End Ordovician Mass Extinction • Second largest mass extinction in the Phanerozoic. • 22% to 26% of all marine invertebrate families went extinct. • 49% to 61% of all marine invertebrate genera went extinct. • 85% of all species went extinct. • Proposed causes for End Ordovician Mass Extinction include: • Major glaciation. • Fall in sea level (reduction in extent of shelf seas). • Loss of warm equatorial oceanic belt. • Oceanic overturn during sea level fall and subsequent rise. • Perturbation of ocean stratification. • Anoxic or toxic deep waters forced onto continental shelves. • Plate tectonic events. • Closure of the Iapetus Ocean. • Loss of shelf habitats. SILURIAN PERIOD (444 to 419 m.y.a.) Silurian Climate and Sea Level • Cold conditions continued from late Ordovician through early Silurian. • Subsequent Silurian was time of general warming and fluctuating sea level. Silurian Paleogeography • Return of epicontinental seas after Ordovician glaciation. • Continued closure of Iapetus Ocean between Laurentia, Baltica, Avalonia, and other microcontinents. • End of Taconic Orogeny. • Caledonian Orogeny. • Rheic Ocean started to narrow. Silurian Evolutionary Events • Recovery of marine animal diversity from End Ordovician Mass Extinction. • Continued diversification of land plants; origin of vascular plants. • Onset of atmospheric CO drawdown by terrestrial photosynthesis. • Colonization of land by arthropods during Late Silurian. 2 3 Ancient Shelly Limestone Environments • E.g., Racine Dolomite (Silurian), Illinois. Terrestrialization of Arthropods • Several arthropod lineages independently colonized land during Late Silurian and Devonian. • Aquatic arthropod communities essentially “marched” onto land. DEVONIAN PERIOD (419 to 359 m.y.a.) Devonian Climate and Sea Level • Climate generally warmed during Devonian. • Sea level fluctuated but was generally high. Devonian Paleogeography • Continued closure of Iapetus and Rheic Oceans. • Caledonian (Acadian) Orogeny as Laurussia assembled from Laurentia, Baltica, and Avalonia. • Aridification of large continental masses lying at latitudes of subtropical highpressure belts. Devonian Evolutionary Events • Radiation of coral bioherms in warm, shallow seas. • Radiation of fish (“Age of Fish”). • Origination of ray-finned and lobe-finned fish in Early Devonian. • Lobe-finned fish evolved into amphibious tetrapods during Late Devonian. • Continued diversification of land plants. • Continued drawdown of atmospheric CO by terrestrial photosynthesis. 2 Late Devonian Mass Extinction • Interval of severe extinction spanning late Frasnian to end Famennian stages. • 21% of all marine invertebrate families went extinct. • Almost 60% of all marine genera went extinct. • 75% of all marine species went extinct. • Tropical bioherm and warm-water shallow marine communities heavily affected. • 75% of brachiopod genera went extinct. • At least two distinct events, spaced over roughly 13 million years, each associated with widespread deposition of organic-rich black shale. • Upper Kellwasser event (end Frasnian extinction). • Hangenberg event (end Famennian extinction). 4 Late Devonian Mass Extinction • Proposed causes for Late Devonian Mass Extinction include: • Development of anoxic oceanic water on shelf. • Low oxygen inhibits microbial decay, resulting in increased burial of organic matter (hence black shale horizons). • Minor glaciations on Gondwana and at high-altitude in tropics. • Global cooling of oceanic waters (with sea level falls). • Extensive volcanism. • E.g., Yakutsk Large Igneous Province (Viluy Traps), eastern Siberia. • (Effects of extensive volcanism discussed in Lecture 21.) CARBONIFEROUS PERIOD (359 to 299 m.y.a.) Carboniferous Climate and Sea Level • Sea level generally rose during early Carboniferous. • Glaciation occurred in later part of Carboniferous (triggered by southward drifting of Gondwana over south pole). • Drop in sea level. Carboniferous Paleogeography • Rising sea level flooded continents. • Vast epicontinental seas. • Widespread deposition of shallow-water, marine shelly limestones. • Later glaciation caused drop in sea level. • Epicontinental seas retreated; lowland terrestrial environments expanded. • Development of coal swamps. • Collision between Laurussia and Gondwana to form Pangaea during Late Carboniferous. • Hercynian and Alleghenian orogenies. Carboniferous Evolutionary Events • Recovery of marine animal diversity from Late Devonian Mass Extinction. • Diverse “crinoid garden” communities in Early Carboniferous seas (see Lab 7). • Diversification of land plants; development of coal swamp forests (see Lab 7). • Continued drawdown of atmospheric CO ; increased atmospheric O levels. • Diversification of terrestrial arthropod communities (see Lab 7). • Diversification of terrestrial vertebrate communities (see Lab 7). • Amphibians. • Earliest reptiles. 2 5 2 PERMIAN PERIOD (299 to 252 m.y.a.) Permian Climate and Sea Level • Climate warmed and glaciers receded during Permian. • Icehouse to greenhouse transition. • Sea level generally fell during Permian. Permian Paleogeography • Continents formed single supercontinent of Pangaea, surrounded by Panthalassic Ocean. • Reduced mid-ocean ridge activity led to sea level fall during Permian. • Epicontinental seas withdrew as sea level fell. • Aridification of large areas of Pangaea beneath subtropical high-pressure belts and on continental interior. Permian Evolutionary Events • Aridification of much of Pangaea resulted in transition from wet coal swamp to dry desert environments. • Decline in diversity and abundance of seedless vascular plants. • Diversification of seed-bearing plants (gymnosperms). • Decline in prevalence of amphibians. • Require water for reproduction and egg-laying. • External fertilization. • Jelly-covered egg must be kept moist (laid in aqueous environment). • Diversification of reptiles. • Don’t require water for reproduction or egg-laying. • Internal fertilization. • Embryo and yolk are enclosed within fluid-filled, shelled, amniotic egg. TAKE-HOME MESSAGES 1. Environmental history of Earth was shaped by physical factors. • Temperature (icehouse versus greenhouse). • Sea level changes. • Plate tectonics (paleogeography). 2. Environmental history of Earth was shaped by biological factors. • Diversification and extinction of lineages. 3. Interaction between biological and physical factors. • Changing physical factors result in mass extinctions. • Diversification of ecosystem engineers changes physical factors. 6 REFERENCES AND ADDITIONAL READING: Books and Scientific Papers: The following books and papers deal with topics covered in this lecture: Barnes, C. R. 2004. Ordovician oceans and climate. Pp. 72-76 in Webby, B. D., F. Paris, M. L. Droser, and I. G. Percival (eds.), The Great Ordovician Biodiversification Event. Columbia University Press, New York. Bond, D. P. G., and P. B. Wignall. 2008. The role of sea-level change and marine anoxia in the Frasnian-Famennian (Late Devonian) mass extinction. Palaeogeography, Palaeoclimatology, Palaeoecology 263: 107-118. Brenchley, P. J. 2004. End Ordovician glaciation. Pp. 81-83 in Webby, B. D., F. Paris, M. L. Droser, and I. G. Percival (eds.), The Great Ordovician Biodiversification Event. Columbia University Press, New York. Brenchley, P. J., J. D. Marshall, and C. J. Underwood. 2001. Do all mass extinctions represent an ecological crisis? Evidence from the Late Ordovician. Geological Journal 36: 329-340. Cooper, R. A., and P. M. Sadler. 2012. The Ordovician Period. Pp. 489-523 in Gradstein, F. M., J. G. Ogg, M. D. Schmitz, and G. M. Ogg (eds.), A Geologic Time Scale 2012. Elsevier, Oxford. 1144 pp. Crampton, J. S., R. A. Cooper, P. M. Sadler, and M. Foote. 2016. Greenhouse-icehouse transition in the Late Ordovician marks a step change in extinction regime in the marine plankton. Proceedings of the National Academy of Sciences 113 (6): 14981503. DiMichele, W. A., H. W. Pfefferkorn, and R. A. Gastaldo. 2001. Response of Late Carboniferous and Early Permian plant communities to climate change. Annual Review of Earth and Planetary Sciences 29: 461-487. Edwards, C. T., M. R. Saltzman, D. L. Royer, and D. A. Fike. 2017. Oxygenation as a driver of the Great Ordovician Biodiversification Event. Nature Geoscience 10: 925-929. Falcon-Lang, H. J., W. J. Nelson, P. H. Heckel, W. A. DiMichele, and S. D. Elrick. 2018. New insights on the stepwise collapse of the Carboniferous Coal Forests: Evidence from cyclothems and coniferopsid tree-stumps near the DesmoinesianMissourian boundary in Peoria County, Illinois, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 490: 375-392. Fan, J.-x., S.-z. Shen, D. H. Erwin, P. M. Sadler, N. MacLeod, Q.-m. Cheng. X.-d. Hou, J. Yang, X.-d. Wang, Y. Wang, H. Zhang. X. Chen, G.-x. Li, Y.-c. Zhang, Y.-k. Shi, D.-x. Yuan, Q. Chen, L.-n. Zhang, C. Li, and Y.-y. Zhao. 2020. A highresolution summary of Cambrian to Early Triassic marine invertebrate biodiversity. Science 367: 272-277. Feulner, G. 2017. Formation of most of our coal brought Earth close to global glaciation. Proceedings of the National Academy of Sciences 114 (43): 11333-11337. Goddéris, Y., Y. Donnadieu, S. Carretier, M. Aretz, G. Dera, M. Macouin, and V. Regard. 2017. Onset and ending of the late Palaeozoic ice age triggered by tectonically paced rock weathering. Nature Geoscience 10: 382-386. 7 Gradstein, F. M., J. G. Ogg, M. D. Schmitz, and G. M. Ogg (eds.), A Geologic Time Scale 2012. Elsevier, Oxford. 1144 pp. Selden, P. A., and J. R. Nudds. 2004. Evolution of Fossil Ecosystems. University of Chicago Press, Chicago. 160 pp. Sepkoski, J. J., Jr. 1981. A factor analytic description of the Phanerozoic marine fossil record. Paleobiology 7 (1): 36-53. Shen, J., A. Pearson, G. A. Henkes, Y. G. Zhang, K. Chen. D. Li, S. D. Wankel, S. C. Finney, and Y. Shen. 2018. Improved efficiency of the biological pump as a trigger for the Late Ordovician glaciation. Nature Geoscience 11: 510-514. Stigall, A. L., R. L. Freeman, C. T. Edwards, and C. M. Ø. Rasmussen. 2020. A multidisciplinary perspective on the Great Ordovician Biodiversification Event and the development of the early Paleozoic world. Palaeogeography, Palaeoclimatology, Palaeoecology 543: 109521. Webby, B. D., F. Paris, M. L. Droser, and I. G. Percival (eds.). 2004. The Great Ordovician Biodiversification Event. Columbia University Press, New York. 484 pp. Zou, C., Z. Qiu, H. Wei, D. Dong, and B. Lu. 2018. Euxinia caused the Late Ordovician extinction: Evidence from pyrite morphology and pyritic sulfur isotopic composition in the Yangtze area, South China. Palaeogeography, Palaeoclimatology, Palaeoecology 511: 1-11. 8