云南墨江下密地早二叠世常么期含地层及化石带  

EARLY PERMIAN FUSULINID-BEARLING STRATA AND FUSULINID ZONES AT XIAMIDI, MEJIANG, YUNNAN

作　　者：周铁明 

机构地区：[1]云南石油地质科学研究所,昆明650200

出　　处：《古生物学报》2000年第4期521-532,共12页Acta Palaeontologica Sinica

摘　　要：简要介绍云南墨江下密地早二叠世常么期含地层 ,对其中类动物群特征作了归纳 ,记述 7属 2 9种 ,其中包括 4新种。依据类化石在该剖面中的垂直分布 ,在常么组建立Eoparafusulinagracilis Eo .mejiangen sis带和Chalaroschwagerinavulgaris Chalaroschwagerinapseudovulgaris带。This paper describes the fusulinids collected from Changmo Formation in the Xiamidi section. This section is stuated at about 1 km west of the Xiamidi village in Mejian county, Yunnan. The Xiamidi section consists of continuous marine sediments, including grey to dark grey bioclastic limestone, thin or medium bedded micritic bioclastic limestone and contain various fossils such as fusulinids, foraminifers, corals and algae. In this section, the stratigraphic succession from the Changmo Formation to Maokou Formation is continuous and extensively exposed in simple structures. The total thickness of Changmo Formation is about 76.69 m.\;The fusulinids are very abundant, with illustrations for 29 species assigned to 7 genera, including 4 new species.\;According to the stratigraphic distribution of the fusulinids in the Changmo Formation, two zones have been recognized (in descending order):\; 2. Chalaroschwagerina vulgaris Chalaroschwa gerina pseudovulgaris Zone; \; 1. Eoparafusulina gracilis Eoparafusulina mej iangensis Zone. DESCRIPTION OF NEW SPECIES Eoparafusulina nagatoformis sp. nov. (Pl.Ⅰ, figs.20, 21)\;Shell large, fusiform, median portion slightly vaulted, polar ends bluntly pointed. Mature specimens having 7—712 volutions about 6.42 —7.81 mm in length and 1.82—2.21 mm in width. Form ratio about 3.53—3.55∶1. The inner volution ellipsoidal and tightly coiled; outer volution loosely expanded, spirotheca thin, composed of a tectum and a keriotheca. Septa fluted in the lateral slopes to poles, median portion plane or weak, septal folds low and hemispherieal. Chomata low, massively developed in the inner volutions. Axtal fillings well defined, occurring almost in the inner whorls. Proloculus small, spherical, about 0.14—0.19 mm in outside diameter.\;Remarks This new species closely resembles Nagatoella in the character of juvenarium, by this character it can be distinguished from other species. Eoparafusulina simaoensis sp. nov. (Pl.Ⅰ, figs.22,

关 键 词：含Ting地层 常么期 Ting化石带 早二叠世 

分 类 号：Q91[天文地球—古生物学与地层学]