Permian Period Notes

Permian Period (299-252 Ma)

Permian Subdivisions

The Permian Period is divided into several epochs and ages, with corresponding regional subdivisions across different continents.

  • Lopingian Epoch (Late Permian)

    • Changhsingian Age: ~254.14 ± 0.07 Ma
    • Wuchiapingian Age: ~259.1 ± 0.5 Ma

  • Guadalupian Epoch (Middle Permian)

    • Capitanian Age: ~265.1 ± 0.4 Ma
    • Wordian Age: ~268.8 ± 0.5 Ma
    • Roadian Age: ~272.95 ± 0.11 Ma

  • Cisuralian Epoch (Early Permian)

    • Kungurian Age: ~283.5 ± 0.6 Ma
    • Artinskian Age: ~290.1 ± 0.26 Ma
    • Sakmarian Age: ~295.0 ± 0.18 Ma
    • Asselian Age: ~298.9 ± 0.15 Ma

Permian Paleogeography

  • Pangea Supercontinent: During the Permian, most of the Earth's landmasses were joined in a supercontinent called Pangea.
  • Panthalassic and Tethys Oceans: The global ocean surrounding Pangea was known as Panthalassic, while the large bay indenting Pangea was the Tethys Ocean.
  • Gondwana Glaciation: Parts of Gondwana (southern continents) were still near the South Pole and experiencing glaciation during the Early Permian (LPIA - Late Paleozoic Ice Age).
  • Northward Movement: Pangea moved northward throughout the Permian Period.

Glaciation and Deglaciation

  • Asynchronous Deglaciation: Terminal deglaciation was asynchronous, starting in western Gondwana during the Middle Pennsylvanian and progressing eastward through the Pennsylvanian and Early Permian.
  • Paraná Basin: The glacial succession of the Paraná Basin played a significant role in understanding glaciation-deglaciation history due to its geographic extent (1.0×106 km21.0 \times 10^6 \text{ km}^2) and correlation with deglaciation cycles in southern Africa.
  • CA-TIMS U-Pb Zircon Ages: Integration of new CA-TIMS U-Pb zircon ages from the Paraná succession with published data from Argentina indicates that glaciation occurred at least by ~335.99 ± 0.06 Ma.
  • Coal Facies and Deglaciation: In the southern Paraná Basin, coal facies directly overlie glacial deposits. Deglaciation occurred approximately 17 million years later, close to the Permian-Carboniferous boundary, around 298.23 ± 0.31 Ma (Candiota A).
  • Volcaniclastic Deposit Age: A volcaniclastic deposit sampled in a coal facies in the Itararé Group yielded an age of 307.7 ± 3.1 Ma. However, the 10 youngest concordant zircon grains produce a recalculated age of 302.0 ± 4.9 Ma, overlapping with the CA-TIMS age of the Candiota coal deposits (298.23 ± 0.31 Ma).

Sonoma Orogeny

  • Permian-Triassic Event: The Sonoma Orogeny was a mountain-building event that reached its peak around the Permian-Triassic boundary.
  • Island Arc Collision: It involved the collision of island arcs with the western margin of North America.
  • Location: The effects are visible in California and Nevada, involving the Sonoman arc.
  • Process: The Sonoman flysch belt thrust over the NAM passive margin (North American Margin), leading to the formation of a new arc with subduction to the east and the beginning of an active Cordilleran margin.

Permian Paleogeography (Early Permian - 275 Ma)

  • Shallow Marine Environments: Dominated the landscape.
  • Deep Marine Areas: Also present alongside shallow marine environments.
  • Lowlands: Undergoing erosion.
  • Mountainous Areas: Also present with volcanoes.

Permian Basin

  • Location: West Texas and New Mexico, including the Guadalupe Mountains.
  • Sediment Thickness: Up to 14,000 feet of lagoon, reef, and basin sediments.
  • Reef Formation: Reefs formed on the basin edges of shallow platforms, composed of algae and over 250 species of invertebrates.
  • Evaporites: Interbedded gypsum and salt deposits formed on the edges of the Permian Basin due to a warm and dry climate.

Permian Deposition

  • Kaibab Limestone (LS): Early to mid-Permian fossiliferous marine limestone, forming the upper cliffs of the Grand Canyon.
  • Phosphoria Formation: Early Permian formation containing phosphorite, mined for phosphorus, and rich in petroleum and trace metals.
  • Evaporites: Vast salt beds in Kansas from the evaporation of Permian seas, plus Permian basin evaporites.
  • Sedimentary Transition: Transition from fossiliferous limestones to shales, oxidized (red bed) clastics, and evaporites.
  • Aridity: Retreat of the ocean and increasing aridity in the later Permian, exemplified by Caprock Canyon red beds and gypsum.

Permian Sea Level

  • Generally Low: Overall, sea levels were generally low during the Permian.
  • Regression of Absaroka: A significant sea level fall occurred during the regression of the Absaroka sequence.

Late Paleozoic Climate

  • Warm Tropics: Most of Europe and North America were warm and tropical, with coal deposits forming in swamps.
  • Cold Gondwana: Gondwana was cold, dry, and glaciated.
  • Climate Change: Major climate change in the late Permian led to “the Great Dying” during the Permo-Triassic mass extinction.