The End Permian s…? Mass Extinction David M. Syracuse, I – Presenter November 17th, 2008 GLY 529
Where are we? When are we? Literature Cited An Example A bah-jillion mya • Something mildly interesting • about the not-so-recent past. 1
Introduction 1 Loss of about 95% of all life on earth.
When was it? 2 About 251 million years ago.
When was it? • In the Phanerozoic Eon. • Start in the Paleozoic Era, end in the Mesozoic Era. • Start in the Permian Period, end in the Triassic Period. • One event in the Guadalupian Epoch. • One event in the Lopingian. 3
The Name • Named for the Kingdom of Perm, in present-day northern Russia.
How do we Know? • The condont Hindeodus parvus is used as a marker. • It first appears in the Triassic. 4
How do we Know? • A familiar professor at the Permian/Triassic Global Stratotype Section and Point in Meishan, China. 5
How do we Know? Black Shale Permian-Triassic Boundary Limestone
The Stage 6 Pangæa
The Stage University of Texas at Austin, Institute for Geophysics, Jackson School of Geosciences PLATES Animation of paleotectonic reconstructions
Permian Conditions • Less Continental Shelf – Pangæa 7
Permian Conditions • Began with glaciers on the poles. 8
Permian Conditions • Large, cool oceans towards the poles. • Warmer equatorial water. • Vast dry areas inland. • Seasonal fluctuations – large areas of land away from water. • Reduced continental shelf area.
Permian Conditions • Pangæa – not much diversity in environment, so not much diversity in organisms? • Arid conditions. • Ripe for a mass extinction already.
The Players • Many sessile organisms lived in reefs. • Large ferns and large insects from Carboniferous. • Many large tetrapods existed. • “Reptilomorph” tetrapods gave way to the beginnings of mammals. • Large conifer forests (gave way to lycopsids)
The Players • Foraminifera (big losses in Guadalupian). • Trilobites (extinct in early Triassic). • Corals, Brachiopods (lost most genera). • Ammonoids, Nautiloids (lost most genera). • Huge sponge reefs (gone). The Tree of Life Project Insects (odonata vs. neoptera) and Mammalian lineages
The Insects • Insects from the carboniferous – fixed wings. • All very large insects (wingspan ≈ 75 cm!) became extinct. • New forms – beetles and flies with foldable wings. • What could have changed so significantly?
The Insects 13 Meganeuropsis permiana
The Insects • Only mass extinction to significantly affect insects. • large insects respired by rapid tracheal contractions. • Atmosphere was not higher in oxygen. • Heat, aridity, and loss of habitat or breeding grounds may have done them in.
The Insects • About 6,500 speices of extant odonata. • Hundreds of thousands of extant neoptera. • Neoptera radiated extensively after the Permian.
The Pre-mammals • Many “reptilomorph” animals show signs of a transition to mammals. • The extinction of larger reptile-like animals paved the way for mammals. • Extreme conditions on Pangæa may have favoured small endothermic beasties.
Mammals, etc. Mammals (you. me. marmosets.) Diapsids (archosaurs, etc.) Therapsids (will give rise to mammals) Large gap in fossil Record! Pelycosaurs(big sails, reptilomorph) Synapsids (first amniotes – Carboniferous)
The Pre-mammals 15 Lystrosaurus
The Causes I 260 mya • The first event was probably an eruption of the Emeishan flood basalts in the Guadalupian Epoch. • Regression due to doming caused loss of shallow-water habitat.
Crustal Doming Crust MOHO Mantle Core
Emeishan flood basalts • Erupted in the Guadalupian. • Affected warm-water marine invertebrates. • Probably killed off most forminiferans. • Regression might be result of doming prior to eruption.
Emeishan flood basalts • Regression then transgression noted at the end of the Guadalupian. • Due to doming? • Caused extinction in shallow marine environments. • Quick recovery.
The Siberian Traps 251 mya • Erupted slightly before the Permian-Triassic boundary. • May have erupted for as long as 1 million years. 12
Is that it? • Two major eruptions. • Loss of habitat from doming. • Couldn’t cause a Mass Extinction.
The Causes II • Emissions from the Traps and other eruptions. • May have significantly changed the atmosphere. • Mainly CO2, CH4 and SO4. • Extended warming. • Reduced Ocean Circulation. • Anoxia in shallow/deep oceans.
The Causes III • Hydrogen Sulfide. • Emitted from bacteria and volcanoes. • May have been stimulated by eutrophic deep waters. • Increased weathering delivers more nutrients to oceans. • Leads to anoxia – sulfur-oxidizing bacteria.
The Causes III • Lacking oxygen, some bacteria can metabolize sulfur, using it as the FEA. • This produces hydrogen sulfide, a poisonous gas. Oxygen – 32 g/mol Nitrogen – 14 g/mol Water – 18 g/mol Carbon dioxide – 44 g/mol 34 g/mol
The Causes III • The gas binds to enzymes in the mightycondrion to stop the production of ATP. • Quick death in high concentrations. • May not have been in high enough concentrations to kill. • Could have caused local extinctions, and chronic stress to organisms.
The Vultures • Lots of stromatolites after the extinction. • Indicates unstable, low-diversity ecosystems. 14
The Vultures • Increase in fungal spores towards end of Permian. • Thus an increase in the need for decomposers. 18
Carbon Isotopes • Different types of plants incorporate different types of carbon (C3 vs. C4). • Amount of carbon in sediments can indicate productivity. • Amounts of 13C took a negative excursion at the end of the Permian. • Both carbonate and organic carbon were reduced.
Land Plants • Vast conifer forests existed in the Permian. • Lycopsids replaced the conifers after the extinction. • Recovery to pre-extinction levels came in the Spathian stage, about 10 million years later 19
Land Plants Conifers Lycopsids 10
The Boundary • No coal deposits in the first part of the Triassic. • No chert. • Black Shales indicate anoxia • No reefs observed for 7 million years.
Lazarus Taxa Forminifera
Lazarus Taxa • Most Lazarus Taxa are filter-feeders. • Could have survived anoxic or dysoxic conditions. • Evidence of migration of species to refugia. • Many Elvis taxa as well, e.g. sponges.