长江下游地区晚泥盆世至早石炭世孢子带和泥盆系-石炭系界线

摘要

Miospores are abundant and well-preserved in the type section of Late Devonian and Early Carboniferous strata in the Lower Yangtze Valley. Based on an extensive study of the Miospores zonation in the Late Devonian and Early Carboniferous strata in the Lower Yangtze Valley, the author holds that there exist seven Miospore assemblege zones, comprising three Late Devonian zones and four Early Carboniferous zones: 1)Rugospora flexuosa-Grandispora cornuta(FC) zone; 2)Vallatisporites pusillites-Retispora lepidophyta (PL) zone; 3)Retispora lepidophyta-Verrucosisporites nitidus(LN) zone; 4)Vallatisporites verrucosus-Retusotriletes incohatus (VI) zone; 5)Spelaeotriletes pretiosus-Cingulizonates bialatus(PB) zone; 6)Schopfites claviger- Auroraspora macra (CM) zone; 7)Lycospora pusilla (PU) zone. A palynological characterization of the Devonian-Carboniferous boundary has, until now, been based on the disappearance ofRetispora lepidophytaand Vallatisporites pusillites.It is quite clear thatVallatisporites verrucosus-Retusotriletes incohatus(VI) zone should beling to Carboniferous, and the boundary between the Devonian and Carboniferous strata in Lower Yangtze Valley should be located at the bottom of the Chenjiabian Formation. The Devonian and Carboniferous miospores undoubtedly play an important role in stratigraphical subdivision and correlation as well as in reconstruction of palaeogeography, palaeontology and palaeoclimates. On the basis of palynological data, the author reassessed the age of the Guanshan Formation and assigned this formation to Late Devonian, and confirmed that theRugospora flexuosa-Grandispora cornuta (FC) zone should correspond to the Upper part of Famennian Formation (Fa2c-Fa2d).%本文系统研究了长江下游地区(包括江苏、浙江和安徽)晚泥盆世和早石炭世孢子50属150余种。根据孢子在地层中的分布和演化规律，建立了7个孢子带，其中晚泥盆世3个带，早石炭世4个带。自下而上依次为：1)Rugospora flexuosa-Grandispora cornuta(FC)带；2)Vallatisporites pusillites-Retispora lepidophyta (PL)带；3)Retispora lepidophyta-Verrucosisporites nitidus(LN)带；4)Vallatisporites verrucosus-Retusotriletes incohatus(VI)带；5)Spelacotriletes pretiosus-Cingulizonates bialatus(PB)带；6)Schopfites claviger-Auroraspora macra(LN)带；7)Lycospora pusilla (PU)带。五通群下部观山组化石孢子丰富，时代相当西欧晚泥盆世法门阶(Famennian)Fa2c-Fa2d。泥盆系和石炭系界线置于陈家边组底部，即3带Retispora lepidophyta- Verrucosisporites nitidus(LN)带和4带Vallatisporites verrucosus-Retusotriltes incohatus(VI))带之间。本文还深入讨论了沉积环境、微古植物地理区、国内外比较等问题。