A Potential Global Standard Stratotype-Section and Point of the Moscovian Stage(Carboniferous)

Conodonts and fusulinids are the two most widely used biotic groups for subdividing and correlating Bashkirian and Moscovian strata. The definition of the base of the Global Moscovian Stage is undecided because there are many disagreements among existing boundary definition proposals,each of which has disadvantages. Declinognathodus donetzianus is easily recognized but somewhat limited in its paleogeographic distribution. Idiognathoides postsulcatus is slightly more widespread, but it is less easily identified and its occurrences may be diachronous from region to region. Diplognathodus ellesmerensis is easily recognized and even more widespread, but it is usually rare and its ancestry is not adequately known. The Naqing Section of South Guizhou, South China contains diverse conodont evolutionary lineages among different taxa, including Idiognathoides, Idiognathodus, Diplognathodus,Neognathodus, Gondolella and Mesogondolella. There are numerous transitional forms in almost every lineage of the Naqing section, which shows that the prospects for South China to play a critical role in determining the basal Moscovian Stage definition are good.

Interpretation of Depositional Environment of Fusulinid Bearing Middle Permian Succession of Bolula and Khaja Ghar Formation, Bamian Zone, Central Afghanistan

The study area belongs to the north Afghanistan having complex tectonic setting, because of separation of the Afghanistan plate from Pangea in Early Permian and its subsequent northward journey and collision with Eurasian plate. The rock exposed in the area belongs to Paleozoic, Mesozoic to Quaternary with Proterozoic basement. Particularly the Permian succession of Afghanistan is rich in fusulinids (larger foraminifera), is age diagnostic, provides strong biostratigraphic tool for the Permian deposits, and has paleobiogeographic applications. The Bamian zone of north Afghanistan has good exposure to Middle Permian and is designated as Bolula and Khaja Ghar Formation is undertaken in this study. The Bolula Formation overlies the greenschist and basalts, composed mainly of carbonate rocks (Dolostone and limestone), having massive limestone, with some quartz and secondary calcite vein in the succession. The intermittent siliciclastic wedges within the carbonate succession are identified as input within the platform with tectonic pulses in the hinterland. Bolula and Khaja Ghar succession is divided into 8 lithofacies ( Facies A to H) and 6 carbonate Facies viz. Sparry calcites limestone, Micritic limestone, Fossiliferous limestones (Biomicrite), Peloidal limestone (Fecal pellets), Interlaminated micritic and sparite limestone, and sandy limestone (micritic). The Bolula and Khaja Ghar Formation in the Bamian area have deposited in a shallow marine shelf environment because of predominance of carbonate rocks and presence of shallow-water marine fossils including fusulinids, small benthic foraminifera, algae, bivalve, brachiopods fragments, corals and bryozoans, etc. In the Bamian zone the unconformity between Upper Carboniferous and Lower Permian;indicates extensive gap in sedimentation, traceable to many parts of Afghanistan as unconformity or tectonic contact is considered here as sequence boundary.

Depositional model of Permian Luodianian volcanic island and its impact on the distribution of fusulinid assemblage in southern Qinghai,Northwest China

Pan-riftizational tectonic activity reached climax at Luodianian (Permian) in the East Tethyan Domain, Qinghai-Tibet Plateau. Because of eruptive volcanics and influence of terrigenous materials, a complex volcanic-sedimentary landform formed on the sea floor in southern Qinghai. Four sedimentary facies types were recognized based on detailed field mapping. Spatially, platform facies volcanic-limestone type was located at the center belt approximately trending NWW, surrounded by shallow water slope facies tuff/tuffite type at the two flanks and deep water slope facies breccia/calcirudite at the most outside. The depression facies sandstone-mudstone type, which comprised mainly mudstone, de-posited between volcanic islands (platform facies volcanic-limestone type). Based on the field map-ping and stratigraphic section data, seven rift-related sedimentary facies were recognized and a depo-sitional model for volcanic island was proposed. It is revealed that some volcanic island chain formed quickly and intermittently in the Qamdo Block during violent eruption, and small carbonate reef, shoal, platform occurred above or on edge of volcanic island, and some slope sedimentary facies surrounded volcano island chain during dormant period of volcanic activities. Three types of fusulinid assemblages were distinguished in the carbonate rocks, which deposited in varied positions of a palaeo-volcanic island: (1) Misellina-Schwagerina assemblage occurred above or on edge of volcanic island, (2) Para-fusulina assemblage was located at restricted depression facies among volcanic islands or carbonate platform, and (3) the reworked Pseudofusulina-Schwagerina assemblage occurred at slope facies near margin of volcanic island, which originally deposited in the shallow-water carbonate platform, then collapsed along the volcanic island margin with fusulinid-bearing grain-supported carbonate con-glomerate or calcirudite, and finally re-deposited on the deeper slope. The sedimentary sequence re-sulting from calm shallow water was deposited at the interior of the Qamdo Block from the Devonian to early Early Permian. At the beginning of the peak period of activity of pan-riftzation (Luodianian), al-ternate volcanic island and shallow marine environment within continent crust came into being. Uni-form and stable shallow-water carbonate platform was formed during the Xiangboan. This suggested that the activity of rift basin was evidently weakened. Subsequently the instability of the basin appre-ciably increased with the occurrence of basalt in late Kuhfengian. At last the whole Qamdo Block turned into the closure period of rift during the Late Permian.

新疆阿尔金山拉配泉地区石炭纪含地层

新疆阿尔金山拉配泉地区石炭系上统下部，被命名为苦水河组，岩性为灰岩、砂岩、泥页岩夹少量硅质岩，含丰富的、非有孔虫、珊瑚、腕足类、海百合茎及钙藻化石。详尽地研究类化石后，可分为３个带：３）Ｐｒｏｆｕｓｕｌｉｎｅｌａｐｓｅｕｄｏｒｈｏｍｂｏｉｄｅｓ－Ｐｒｏｆｕｓｕｌｉｎｅｌａｐａｒａｒｈｏｍｂｏｉｄｅｓ带；２）Ｐｒｏｆｕｓｕｌｉｎｅｌａｐｒｉｓｃａ－Ｐｒｏｆｕｓｕｌｉｎｅｌａｏｖａｔａ带；１）Ｅｏｓｔａｆｆｅｌａｐｏｓｔｍｏｓｑｕｅｎｓｉｓ－Ｐｓｅｕ－ｄｏｓｔａｆｆｅｌａａｎｔｉｑｕｅｖａｒ．ｐｏｓｔｅｒｉｏｒ带。苦水河组可与新疆塔里木盆地西南缘的卡拉乌依组对比。

Ni-Ir anomaly and fusulinid extinction across the Permian-Triassic boundary in Dongluo, Guangxi

SINCE Alvarez first used iridium anomaly to explain the Cretaceous-Tertiary impact eventand mass extinction, more than 70 sites of iridium-nickel anomalies have been found. The Per-mian-Triassic boundary extinction is more prominent than that of the Cretaceous-Tertiary.This leads us to make research on whether similar events happened during that period.

LATE CARBONIFEROUS FUSULINID BIOSTRATIGRAPHICAL SEQUENCE IN STRATIGRAPHICAL REGION OF NORTH CHINA

Based upon the research materials from Shanxi, Hebei, Henan, Jiangsu, Shan- dong, Anhui and Shaanxi provinces, the Late Carboniferous fusulinid biostrati- graphical sequence in stratigraphical region of North China can be subdivided from bottom upwards into the following zones.

Ultrastructures in the Spirotheca of Fusulinella (Fusulinid foraminifer)

An SEM study has been conducted to examine the ultrastructures in the spirotheca of Fusulinella and to reveal the ultra-features of the basic layers consisting of the spirotheca of Fusulinella. The study has demonstrated that the diaphanotheca in the spirotheca of Fusulinella could be considered as a secondary structure.