TY - JOUR A1 - Wang, Xiaoxi A1 - Foster, William J. A1 - Yan, J. A1 - Li, A. A1 - Mutti, Maria T1 - Delayed recovery of metazoan reefs on the Laibin-Heshan platform margin following the Middle Permian (Capitanian) mass extinction JF - Global and planetary change N2 - Following the Middle Permian (Capitanian) mass extinction there was a global ‘reef eclipse’, and this event had an important role in the Paleozoic-Mesozoic transition of reef ecosystems. Furthermore, the recovery pattern of reef ecosystems in the Wuchiapingian of South China, before the radiation of Changhsingian reefs, is poorly understood. Here, we present a detailed sedimentological account of the Tieqiao section, South China, which records the only known Wuchiapingian reef setting from South China. Six reef growing phases were identified within six transgressive-regressive cycles. The cycles represent changes of deposition in a shallow basin to a subtidal outer platform setting, and the reefal build-ups are recorded in the shallowest part of the cycles above wave base in the euphotic zone. Our results show that the initial reef recovery started from the shallowing up part of the 1st cycle, within the Clarkina leveni conodont zone, which is two conodont zones earlier than previously recognized. In addition, even though metazoans, such as sponges, do become important in the development of the reef bodies, they are not a major component until later in the Wuchiapingian in the 5th and 6th transgressive-regressive cycles. This suggests a delayed recovery of metazoan reef ecosystems following the Middle Permian extinction. Furthermore, even though sponges do become abundant within the reefs, it is the presence and growth of the encrusters Archaeolithoporella and Tubiphytes and abundance of microbial micrites that play an important role in stabilizing the reef structures that form topographic highs. KW - Reefs KW - Mass extinction KW - Wuchiapingian KW - Archaeolithoporella KW - Permian Y1 - 2019 U6 - https://doi.org/10.1016/j.gloplacha.2019.05.005 SN - 0921-8181 SN - 1872-6364 VL - 180 SP - 1 EP - 15 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Foster, William J. A1 - Lehrmann, Daniel J. A1 - Yu, Meiyi A1 - Martindale, Rowan C. T1 - Facies selectivity of benthic invertebrates in a Permian/Triassic boundary microbialite succession: Implications for the "microbialite refuge" hypothesis JF - Geobiology N2 - Thrombolite and stromatolite habitats are becoming increasingly recognized as important refuges for invertebrates during Phanerozoic Oceanic Anoxic Events (OAEs); it is posited that oxygenic photosynthesis by cyanobacteria in these microbialites provided a refuge from anoxic conditions (i.e., the "microbialite refuge" hypothesis). Here, we test this hypothesis by investigating the distribution of ~34, 500 benthic invertebrate fossils found in ~100 samples from a microbialite succession that developed following the latest Permian mass extinction event on the Great Bank of Guizhou (South China), representing microbial (stromatolites and thrombolites) and non-microbial facies. The stromatolites were the least taxonomically diverse facies, and the thrombolites also recorded significantly lower diversities when compared to the non-microbial facies. Based on the distribution and ornamentation of the bioclasts within the thrombolites and stromatolites, the bioclasts are inferred to have been transported and concentrated in the non-microbial fabrics, that is, cavities around the microbial framework. Therefore, many of the identified metazoans from the post-extinction microbialites are not observed to have been living within a microbial mat. Furthermore, the lifestyle of many of the taxa identified from the microbialites was not suited for, or even amenable to, life within a benthic microbial mat. The high diversity of oxygen-dependent metazoans in the non-microbial facies on the Great Bank of Guizhou, and inferences from geochemical records, suggests that the microbialites and benthic communities developed in oxygenated environments, which disproves that the microbes were the source of the oxygenation. Instead, we posit that microbialite successions represent a taphonomic window for exceptional preservation of the biota, similar to a Konzentrat-Lagerstatte, which has allowed for diverse fossil assemblages to be preserved during intervals of poor preservation. KW - anoxia KW - extinction KW - microbialite KW - Permian KW - Triassic KW - refuge Y1 - 2019 U6 - https://doi.org/10.1111/gbi.12343 SN - 1472-4677 SN - 1472-4669 VL - 17 IS - 5 SP - 523 EP - 535 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Foster, William J. A1 - Heindel, Katrin A1 - Richoz, Sylvain A1 - Gliwa, Jana A1 - Lehrmann, Daniel J. A1 - Baud, Aymon A1 - Kolar-Jurkovsek, Tea A1 - Aljinovic, Dunja A1 - Jurkovsek, Bogdan A1 - Korn, Dieter A1 - Martindale, Rowan C. A1 - Peckmann, Jörn T1 - Suppressed competitive exclusion enabled the proliferation of Permian/Triassic boundary microbialites JF - The Depositional Record : the open access journal of the International Association of Sedimentologists N2 - During the earliest Triassic microbial mats flourished in the photic zones of marginal seas, generating widespread microbialites. It has been suggested that anoxic conditions in shallow marine environments, linked to the end-Permian mass extinction, limited mat-inhibiting metazoans allowing for this microbialite expansion. The presence of a diverse suite of proxies indicating oxygenated shallow sea-water conditions (metazoan fossils, biomarkers and redox proxies) from microbialite successions have, however, challenged the inference of anoxic conditions. Here, the distribution and faunal composition of Griesbachian microbialites from China, Iran, Turkey, Armenia, Slovenia and Hungary are investigated to determine the factors that allowed microbialite-forming microbial mats to flourish following the end-Permian crisis. The results presented here show that Neotethyan microbial buildups record a unique faunal association due to the presence of keratose sponges, while the Palaeotethyan buildups have a higher proportion of molluscs and the foraminifera Earlandia. The distribution of the faunal components within the microbial fabrics suggests that, except for the keratose sponges and some microconchids, most of the metazoans were transported into the microbial framework via wave currents. The presence of both microbialites and metazoan associations were limited to oxygenated settings, suggesting that a factor other than anoxia resulted in a relaxation of ecological constraints following the mass extinction event. It is inferred that the end-Permian mass extinction event decreased the diversity and abundance of metazoans to the point of significantly reducing competition, allowing photosynthesis-based microbial mats to flourish in shallow water settings and resulting in the formation of widespread microbialites. KW - Competitive exclusion KW - Permian KW - Triassic KW - mass extinction KW - microbialites KW - palaeoecology Y1 - 2019 U6 - https://doi.org/10.1002/dep2.97 SN - 2055-4877 VL - 6 IS - 1 SP - 62 EP - 74 PB - Wiley CY - Hoboken ER -