General conclusions

• All continents were now merged into the super-continent Pangaea.
• Most cratons were high standing or emergent as compared to most of the prior Paleozoic.
• The configuration of tectonic events leading up to Pangaea came to a close and the period became on of comparative tectonic quiescence.
• The Permian Period ended with the "MOTHER OF ALL EXTINCTIONS".
• More than 90% of all marine species disappeared or were greatly reduced.
• even greater than prior Ordovician and Devonian extinctions and the "famous" Cretaceous/Tertiary extinction
• marine invertebrates were severly impacted
• spore bearing plants were replaced by gymnosperms as dominant plants

• Shallow Pennsylvanian epeiric seas had occupied much of west and central North America.
• During the Permian, over large areas, the seas withdrew from these areas becoming dry land.
• The Ancestral Rockies were a major source of clastic material to their surrounding basins which filled with red bed formations. Alluvial fans, rivers and streams spread arkoses, sandstones, conglomerates, mudstones into the surrounding basins. Sediment type primarily was determined by the distance to the source, mode of transport, and source geology (often PreCambrian granites). One such formation, in the Four Corners area of the UF Geology Field Camp, is the Cutler Formation (sandstones, conglomerates, and mudstones).

• Location: West Texas and SE New Mexico

• During the Permian, the southern edge of a carbonate producing platform in the southwest was a narrow region in southern New Mexico and west Texas. As a consequence of Ouachita orogeny, a portion of this area formed a foredeep ( a downwarped "trench" adjacent to a island arc or orogenic belt) basin.
• This foredeep basin was actually two basins, the Midland Basin to the east (Texas) and the Delaware Basin to the west (New Mexico-Texas), separated by a Central Basin Platform.

• 1. It is one of the few places where you can see exposed Permian reef- basin facies relationships.
• 2. The barrier reef and Delaware Basin are exposed similar to their Permian topographic relationship.
• 3. The occurrence of some of the most spectacular caves and cave formations in the world (Carlsbad Caverns National Park and another even more spectacular cave system nearby).
• 4. The occurrence of major oil and gas deposits throughout the region.

• Earliest Permian basin subsidence with deposition of organic rich shakes and dark limestones.
• Mid-Permian carbonate banks form around the margins of the basins with small reefs. By late Middle Permian enormous barrier reefs formed (now exposed in the Quadalupe Mountains).
• Subsidence stopped in the Midland Basin, allowing it to silt up and become part of the carbonate platform.
• Restricted circulation into the Delaware Basin and more restricted circulation on the carbonate platform caused major evaporite formation.

• Reef carbonates: Goat Seep and Capitan limestones Basin and platform evaporites: Castille, Salida, and Rustler Formations. others
  Topics for classroom discussion

• How do the assemblages of the Permian reefs differ from those of the earlier Paleozoic?
• How do the caves of the Quadalupe Mountains differ from many other caves (e.g. Mammoth Cave) as to their modeof formation?
• What are the source rocks and reservoir rocks of these Permian Basins?

What was the cause(s) of the terminal Permian extinctions?
 
 

• The Late Permian extinction was the largest in Earth history (90% of all marine species extinct or greatly reduced)and marks the Paleozoic-Mesozoic boundary. The extinctions were spread over the last two stages of the Permian (~7 m.y.)

• Nature of the the Paleozoic/Mesozoic boundary:

• The Victims:

• Reductions of other groups:

• Terrestrial Plant and Animal Extinctions:

          2.Plants
                  continuity, except disappearance of cordaites
                  former large sphenopsids and lycopsids reduced to shrub-like plants
 

• Cause(s) of extinction:

2. Depletion of atmospheric oxygen oxidation of organic carbon may have reduced atmospheric oxygen from 30 to 15%

3. Depletion of oceanic nutrients by oxidation of enormous amounts of previously buried organic carbon exposed by low-stand conditions.

• no evidence

• Glaciation: Permian glacial deposits are found throughout Gondwana, however, main phase was in the middle Permian
• Also Middle Permian glaciation in Antarctica
• Upper Permian fossil wood in Antractica, warm, mildly seasonal conditions
• Latest Permian global warming
• climatic instability