Proliferation of Early Triassic wrinkle structures: Implications for environmental stress following the end-Permian mass extinction

摘要: Lower Triassic strata in the western United States and northern Italy have yielded first reported occurrence of microbially mediated wrinkle structures shallow subtidal siliciclastic paleoenvironments since Cambrian. We hypothesize that formed under reduced infaunalization conditions during aftermath end-Permian mass extinction. These occur sedimentary rocks association with hummocky cross-stratification and, some cases, trace fossils such as Asteriacites , Rhizocorallium Planolites Gyrochorte indicate a paleoenvironment. Wrinkle were found Campil Member Werfen Formation Virgin Limestone Moenkopi upper member Thaynes exposed States. The presence is likely related to unique taphonomic window allowed for preservation these delicate features on storm-dominated shelves. commonly variety Proterozoic–Cambrian, but thereafter became restricted intertidal-supratidal deep-sea environments. This restriction has been attributed increase metazoans following Cambrian radiation. proliferation settings Early suggests infaunal bioturbation was after extinction this reduction lasted millions years.