Chapter 12 Environmental trends of Early Triassic biofabrics: implications for understanding the aftermath of the end-Permian mass extinction

摘要: Abstract The Lower Triassic Virgin Limestone Member of the Moenkopi Formation provides a holistic picture lag phase biotic recovery in aftermath end-Permian mass extinction. This unit records deposition siliciclastic and carbonate nearshore to mid-shelf palaeoenvironments western United States during latest Early (Spathian) time. Nearshore siliciclastic-dominated units are characterized by relatively diverse trace fossil assemblage, including vertical traces such as Rhizocorallium Arenicolites , but record low ichnofabric indices. Middle shelf carbonate-dominated units, however, contain diversity assemblage dominated simple horizontal tend high Subtidal microbial structures occur wrinkle strata stromatolitic thrombolitic buildups strata. strong variations assemblages, indices, development across onshore-offshore transect demonstrate that an examination variety facies different is required reveal true recovery. In addition, prolonged absence deep bioturbation distribution fabrics subtidal carbonates siliciclastics indicates return Phanerozoic-style substrates suggests environments continued experience environmental stress, perhaps episodically, for 4–7 million years after