Record of the Late Paleozoic Ice Age From Tarim, China

<abstract xml:lang="en" type="main">The late Paleozoic ice age was one of the three major glaciations in the Phanerozoic. However, the influence and characteristics of this glaciation and deglaciation remain unclear. In this study, we present lithostratigraphy, biostratigraphy, and chemostratigraphy during the Late Mississippian to the Early Permian in Tarim, Northwestern China. Tarim records two Gondwana glacial events in the Serpukhovian-Moscovian (Glacial II) and the Asselian-Sakmarian (Glacial III). Together with the global evidence of isotopes and sea level changes, multipulsed growth and decay of Glacial II and III are confirmed. The Serpukhovian isotopic pattern in Tarim exhibits a negative δ¹³C excursion of -6.6‰, which is comparable to those recorded in other continents. This negative excursion and contemporaneous sea level fall are triggered by the expansion of the ice sheets of Glacial II. The glaciation maximum is marked by the global sea level fall during the Bashkirian. A two-stage transgression and positive shifts of δ¹³C from the Tarim and Laurussia represent evidence of stepwise deglaciation of Glacial II during the Moscovian. Positive δ¹⁸O excursions in Tarim and other two global sections from Laurussia and the regression during early Asselian to early Sakmarian are linked to the Glacial III, confirming this event is of global origin. The eustatic rise and the negative δ¹⁸O shifts indicate the retreat of this Gondwana glacier in late Sakmarian. These continuous data sets in Tarim coupled with time equivalent stratigraphy and geochemical records provide insights into the multistage evolution of the discrete Glacial II and III events.<abstract xml:lang="en" type="synopsis">The late Paleozoic ice age (LPIA) spanning from Late Devonian to Late Permian is among the major global icehouses in the Phanerozoic. Previous studies of the LPIA in southern Gondwana proposed a hypothesis of a single, prolonged LPIA. An alternative hypothesis argues for a more dynamic view that the LPIA consisted of a series of discrete, short-lived, and possibly asynchronous glaciations. However, the onset, development, and demise of the discrete glaciations are not clearly understood. In this contribution, we provide continuous data sets of carbon and oxygen isotopes from the biostratigraphically constrained strata covering the LPIA in Tarim, China. Evidence of microfacies and sedimentology, as well as isotope data, provide clues for sea level changes related to waxing and waning of the late Paleozoic glaciations. A global synthesis of carbon and oxygen isotope data and sea level evidence provides insights into the LPIA and supports the second hypothesis of a dynamic LPIA.<abstract xml:lang="en" type="short"><list xml:id="ggge22342-list-0001" style="bulleted"><listItem xml:id="ggge22342-li-0001">δ¹³C and δ¹⁸O data sets covering the late Paleozoic ice age from Tarim record two Gondwana glacial events in the Serpukhovian-Moscovian and Asselian-Sakmarian<listItem xml:id="ggge22342-li-0002">δ¹³C excursion and sea level fall were triggered by the Serpukhovian-Moscovian glaciation<listItem xml:id="ggge22342-li-0003">δ¹⁸O excursion and reef complex indicate the retreat of the Asselian-Sakmarian glaciation</list>