Hao, Y. -c.; Lin, J. -x. (1982). 论粤、桂、湘、鄂二叠纪有孔虫的组合特征 - Permian foraminiferal assemblages in Guangdong, Guangxi, Hunan and Hubei. Earth Sciences. Journal of Wuhan College of Geology. 1982(1): 19-33.

340839

Hao, Y. -c.; Lin, J. -x.

1982

1982(1): 19-33

Publication

Permian forams (excluding fusulinids) discovered so far in the region covering Guangdong, Guangxi, Hunan and Hubei are represented by warm water forms resembling the Tethys fauna in nature.The abundant and wides- pread genera such as Pachyphloia, Robuloides and Padangia of this region are commonly encountered in the contemporaneous Tethys fauna. Colaniella and Pseudocolaniella occurring in this region are typical forms of the latter. Five assemblages are recognized on the basis of their distinct taxa, distribution and ecological characteristics (Table 1 ). Early Permian assemblages: 1. The Hemigordius decorus-Multidiscus pygmaeus assemblage occurs in the lower part of Lower Permian Qixia Formation. The Horizon containing this assemblage is equivalent to the fusulinid zone of Misellina claudiae. Main elements of this assemblage are Hemigordius decorus, H. parvulus, H. ovatus, Multidiscus pygmaeus, Cribrogenerina cylindrica, Globivalvulina graeca and Pseudoglandulina inepta. The assemblage is rich in carbonatites intercalated with carbonaceous mudstone or thin coal seams, in the south of Jiangnan Massif. The equivalent beds in the north of this massif are terrestrial coalbearing series without foraminifera. 2. The Eolasiodiscus-Neodiscus maopingensis assemblage ranging from the middle to upper parts of Qixia Formation is predominated by Eolasiodis-cus which reached its climax of development during middle to late Early Permian. Other profuse elements of the assemblage are Padangia, Nodosaria, Geintzina, Pachyphloia and Glomospira in association with a few species of Neoendothyra, Cribrogenerina, Climacammina and Hemigordius. Strata containing this assemblage are bioclastic limestone with thin interealations of marl and calcareous mudstone which are equivalent to the fusulinid zones of Nankinella orbicularia and Cancellina-Parafusulina multiseptata. 3. The Hemigordiopsis orientalis-Multidiscus robustatus assemblage is found in the Lower Permian Maokou Formation in association with fusulinid zones of Neoschwagerina and Yabeina. It is the most abundant among all the Permian assemblages. Its most common and best developed species are Multidiscus robustatus, Neoendothyra permica, Globivalvulina bulloides, Cribrogenerina nana, C. obesa, Climacammina valvulinoides, Pachyphloia angulata, P. ovata, P. multiseptata, P. lanceolata and Geintzina tcherdynjewi. Hemigordiopsis orientalis and Multidiscus robustatus are reported only from the Maokou Formation in the region studied. Occurring in diferent facies of carbonatites this assemblage has a wide geological distribution due to the euryhaline character of most of its taxa. However, it is very abundant in pure limestone, but scarce in dolomitic limestone and appears in small amount in siliceous limestone yielding no fusulinids and other fossils. Late Permian assemblages: 4. The Septoglobivalvulina guangxiensis-Robuloides gibbus assemblage is encountered in biodetrital limestone of the early Late Permian Wujiaping Formation. Being monotonous, poorly preserved and predominated by uniserial forms, this assemblage is much less abundant in both taxa and populations than those of the Early Permian. This indicates that there was a degeneration of foraminiferal fauna at the beginning of Late Permian. The most predominant and widespread species of this assemblage is Robuloides gibbus while Septaglobivalvulina guangxiensis appears only in this assemblage. Other abundant forms including Pachyphloia, Nodosaria and Pseudoglandulina, This assemblage is well-developed in bioclastic limestone in equivalent with the fusulinid zone of Codonofusiella lui in central and western Guangxi, eastern part of northern Hunan and some localities of western Hubei. In other areas of the region studied where clastic or siliceous sediments accumulated, foraminifera have not been found or have been found to be in poor preservation. 5. The Colaniella-Robuloides acutus assemblage occurring in the late Late Permian Changxing Formation is characterized by the pressence of Colaniella and Pseudocolaniella

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