Tetsuo Sugiyama

Diversity and extinction patterns of Permian coral faunas of China

Coral diversity and extinction patterns in the Permian of China are revealed through statistical analyses of 56 coral families, 263 genera and 2100 species from five consecutive time intervals. The highest coral diversity is in the Chuanshanian, with 753 species, 167 genera and 39 families. In contrast, the lowest diversity is in the Changhsingian, with only 68 species, 20 genera and 10 families. Two decreases in diversity can be recognized during the Permian. The first occurred at the end of the Maokouan (end-Guadalupian) and is marked by the loss of 75.6% of coral families, 77.8% of coral genera and 82.2% of coral species. The second major diversity drop took place at the end of the Changhsingian, when all rugose and tabulate corals became extinct. The extinction at the end of the Guadalupian in Pangea may be related to the middle Permian global regression. However, in South China the end-Maokouan extinction may be related to the eruption of the Omeishan Basalt. A triple-zoned palaeobiogeographical pattern is well expressed by coral diversity.

Late Paleozoic faunal, climatic, and geographic changes in the Baoshan block as a Gondwana-derived continental fragment in southwest China

Abstract The Carboniferous and Permian of the Baoshan block consist of three major depositional sequences: a Lower Carboniferous carbonate sequence, a Lower Permian siliciclastic sequence, and a Middle Permian carbonate sequence. These three sequences were interrupted by two major regressive events: first, the Namurian Uplift ranging in age from Serpukovian to Gzhelian, and second, the Post-Sakmarian Regression occurring probably at Artinskian time in the Baoshan block, although the precise time interval of the latter event is still unclear. The Baoshan block is characterized by warm-water, highly diverse and abundant faunas during the Early Carboniferous, by cold-water and low diversity faunas during the Early Permian, and by possibly warm-water but low diversity faunas during the Middle Permian. The Sweetognathus bucaramangus conodont fauna constrains the upper boundary of the diamictite-bearing siliciclastic deposits (Dingjiazhai Formation) to the Sakmarian to early Artinskian, as well as the eruption of the rifting basalts (Woniusi Formation) to, at least, the post-early Artinskian. Paleozoogeographically, affiliation of the faunas in the Baoshan block changed from Eurasian in the Early Carboniferous, to Peri-Gondwanan in the Early Permian, and to Marginal Cathaysian/Cimmerian in the Middle Permian. Cimmerian blocks have more or less comparable geohistory to one another in the Carboniferous and Permian. During the Middle Permian, the eastern Cimmerian blocks such as Sibumasu (s.s), Baoshan, and Tengchong are not far from the palaeoequator, but apparently more distant than the western Cimmerian blocks based on the presence or absence of some index taxa such as the fusulinaceans Eopolydiexodina and Neoschwagerina , and the corals Thomasiphyllum and Wentzellophyllum persicum .

Late Palaeozoic corals of Tibet (Xizang) and West Yunnan, Southwest China: successions and palaeobiogeography

Abstract A dynamic pattern of coral faunal provincialism in the Carboniferous to Permian sequence is preserved in Tibet–West Yunnan. During the Early Carboniferous, an undifferentiated Eurasian province was present, containing the Kueichouphyllum , Keyserlingophyllum - Siphonophyllia , and Cyathaxonia faunas, that reflect major environmental differences relative to previous interpretations. During the Late Carboniferous–Early Permian, the Indoralian province and the Cathaysian province can be distinguished. The former is recognised by an absence of Late Carboniferous–Asselian corals and by the presence of the Sakmarian–Artinskian Cyathaxonia fauna. The latter contains the Late Carboniferous and Early Permian compound corals Nephelophyllum and Kepingophyllum . As many blocks drifted northward beginning in the late Early Permian, the Indoralian province had evolved into two discrete provinces: the Himalayan and Cimmerian provinces. The Himalayan province as a relic of the Indoralian province was in the northern margin of Gondwanaland. The Cimmerian province between the Himalayan and the Cathaysian provinces consists of the present tectonic blocks: Lhasa, Qiangtang, Tengchong, and Baoshan in Tibet and West Yunnan. It is characterised by Roadian non-dissepimental solitary corals and Wordian–Capitanian compound Waagenophyllidae, as well as some endemic Cimmerian taxa such as Thomasiphyllum and Wentzellophyllum persicum . The Cathaysian province is dominated by Szechuanophyllum and Ipciphyllum . During the Late Permian, the Himalayan province and the Cathaysian province can be recognised. The former contains only small solitary corals, referred to as the Lytvolasma fauna, and the latter is identified by Liangshanophyllum , a fasciculate waagenophyllid.

Permian of West Yunnan, Southwest China: a biostratigraphic synthesis

Recent progress in the study of Permian stratigraphy of western Yunnan, southwest China, is reviewed with particular references to the Tengchong and Baoshan blocks and the Changning–Menglian Belt. Where confusion or controversy exists in stratigraphical nomenclature and/or dating, we attempt to clarify the situation based on our recent field observations and newly obtained research results. The Permian within the Changning–Menglian Belt embraces different stratigraphic successions, suggesting different tectonic settings, ranging from passive margin and active margin, to oceanic basin and seamounts. Permo-Carboniferous faunas in the carbonate sequences of the Changning–Menglian Belt are of typical Cathaysian affinity, as demonstrated by abundant fusulinaceans and compound rugose corals. The Permian stratigraphy and faunas of the Tenchong and Baoshan blocks are markedly different from those of the Changning–Menglian Belt. The Baoshan Block lacks Upper Carboniferous deposits, and its subsequent Lower Permian sequence consists predominantly of siliciclastic strata yielding cool-water faunas and possibly glaciogene diamictites, overlain by thick basaltic lava and volcaniclastics of probably rift origin. The upper part of the Permian in the Baoshan Block is characterized by carbonates containing mixed Cathaysian and Gondwanan faunas. The Tengchong Block has a similar evolutionary history to the Baoshan Block, but completely lacks volcanic rocks.

Permian coral faunas of the eastern Cimmerian Continent and their biogeographical implications

Abstract Because of a depositional hiatus, Late Carboniferous corals are unknown from the eastern Cimmerian Continent. Early Permian (Asselian to Artinskian) corals are characterized by non-dissepimented solitary forms, and the absence of Kepingophyllidae and Waagenophyllidae, forms common in the Cathaysian biotic province. Roadian faunas in most areas of the eastern Cimmerian Continent are dominated by small solitary corals. These faunas are quite different from those of the Cathaysian area, where abundant large solitary and compound corals occur. By the Wordian, and into the Capitanian, large solitary and massive Waagenophyllidae, with a Cathaysian aspect, were well developed and widespread in the Cimmerian Continent. However, some endemic taxa, like Thomasiphyllum, also occur. Late Permian corals consist only of Cathaysian elements. Therefore, paleobiogeographically, the coral faunas in the eastern Cimmerian Continent reveal the following changes: (1) a Peri-Gondwanan affinity during the Early Permian to early Middle Permian, (2) an endemic Cimmerian–Cathaysian affinity during the late Middle Permian, and (3) a true Cathaysian fauna during the Late Permian. These changes may be related to the rifting of the Cimmerian Continent from Gondwanaland in the Late Early Permian and its subsequent northward drift.

MIDDLE PERMIAN RUGOSE CORALS FROM LAIBIN, GUANGXI, SOUTH CHINA

Abstract The Middle Permian Chihsia and Maokou formations in Laibin, central Guangxi, South China contain 19 rugose coral species; of these taxa, Lophocarinophyllum sandoi, Asserculinia solida, and Innixiphyllum wuae are new. Innixiphyllum represents a new genus characterized by contratingent minor septa. Ten species are reviewed and described in detail, and the diagnoses of three of these species, Allotropiophyllum heteroseptatum (Grabau, 1928), Lophocarinophyllum taihuense (Yan and Chen, 1982), and Ipciphyllum regulare (Wu, 1963), are newly emended. The morphological variation and ontogenetic changes of the solitary, nondissepimented species are particularly emphasized. Six additional taxa are described and illustrated but are left in open nomenclature. The corals from Laibin are typically Tethyan. Four biostratigraphic assemblages are recognized: an assemblage of massive corals in the upper Chihsia Formation represented by Polythecalis longliensis; an assemblage of small solitary and nondissepimented corals in the lower Maokou Formation, dominated by species of Allotropiophyllum, Innixiphyllum and Lophocarinophyllum; an assemblage of mixed massive colonial and small solitary corals in the middle Maokou Formation, characterized by Ipciphyllum regulare; and an assemblage of solitary nondissepimented corals in the uppermost Maokou Formation, characterized by Ufimia elongata. These assemblages correspond well to those from other areas of South China. In Laibin, only two rugose taxa, Amplexocarinia sp. and Paracaninia minor, occur in the basal part of the Wuchiaping Formation of Lopingian age.

A new Moscovian foraminiferal fauna from Huai Luang, east of Wang Saphung, Changwat Loei, Northeast Thailand

Abstract The unusual rarity of Fusulinella species is one of the most interesting characteristics among the known Moscovian foraminiferal faunas in Thailand. Earlier an occurrence of Fusulinella bocki von Moller was documented in Northeast Thailand but with neither description nor illustration. For the first time, we have recently discovered a small foraminiferal fauna characterized by two Fusulinella species ( F. bocki von Moller and F. praebocki Rauser-Chernoussova) from a limestone collected at Huai Luang, about 5 km east of Wang Saphung, Changwat Loei, Northeast Thailand, where the Fusulina pulchella fauna was reported previously. Geological evidence suggests that our foraminiferal fauna most certainly came from the strata referable to the Fusulina pulchella Zone although F. pulchella Gryzlova is absent from our fauna. The present discovery of a Fusulinella -bearing foraminiferal fauna from Huai Luang, indicative of a Late Moscovian age (most probably to the Myachkovsky Horizon in the Russian standard scheme), provides important data to clarify the faunal composition of the Fusulina pulchella Zone and to compare the Late Moscovian foraminiferal faunal affinity in the Loei-Wang Saphung area with those of the type and reference sections. In this paper, six species of fusulinaceans are described, and coexisting smaller foraminifers are listed and illustrated.