摘要
四川江油—广元地区上石炭统碳酸盐岩发育良好,厚度不大,化石丰富,含多层紫红色砾屑生物碎屑灰岩和泥岩韵律层,在整个华南同期沉积中颇具特色。根据野外观察和室内显微分析,共识别出15种微相类型。根据这些微相类型在纵向和横向上的组合与分布特点,参考Wilson的标准微相和镶边碳酸盐岩台地沉积模式,利用微相组合分析将这些微相组合划分到4个相带,即蒸发台地、局限台地、开阔台地和台地边缘浅滩。沉积相带的变化特征表明研究区晚石炭世存在着多期海侵—海退旋回,其中在黄龙组上段沉积中期海侵达到最大值,使得川西北大部分地区和川东地区广泛接受碳酸盐岩沉积。江油—广元地区上石炭统特殊岩层的研究表明:黄龙组下部4套红层具有浅海陆棚上部近积风暴岩的特征;船山组核形石灰岩粒序层及其地球化学特征表明核形石的形成可能与晚石炭世晚期全球冰期事件有密切的关系。
The Jiangyou-Guangyuan area, which is located in the north margin of the Longmen Mountain Nappe Struc- tural Belts, is one of the classic areas for the upper Carboniferous researches in Sichuan Basin and even in the upper Yangtze Plate. The upper Carboniferous was deposited in semi-enclosed gulfs of the western Yangtze Block, which char- acterized by slight thickness, light color, many fossils and several fuchsia mudstone and containing gravels bioclastic limestone as a set of semi-restricted platform and open platform carbonate rocks in this area. The strata are revised ac- cording to sedimentary types, sedimentary structures, lithological characters, and paleontological combinations. The up- per Zongchanggou Formation, which was considered as one part of the lower Carboniferous, is amended to the upper Carboniferous Huanglong Formation in this paper. The upper Carboniferous is divided into four parts, as lower Huan- glong Formation, middle Huanglong Formation, upper Huanglong Formation and lower Chuanshan Formation. Fifteen microfacies can be divided according to field observation, laboratory micro-analysis and classification of car- bonate rocks by Dunham, as Unfossiliferous mudstones （MFI-1）, Clastizoic mudstones （MF1-2）, Calcareous green al- gae wackestones （ MF2-1 ）, Bioclastic wackestones （ I^IF2-2）, Birdseyes-Fenestral pelletoid packstones （ MF3 ）, Bivalve wackestones （MF4-1）, Bivalve packstones （MF4-2）, Calcareous green algae packstones （MF5-1）, Fusulinid pack- stones （MF5-2）, Bioclastic wackestones with oncoids （MF5-3）, Bioclastic wackestones （MF5-4）, Fine- grained pe- loid grainstones （MF6）, Bioclastic grainstones （MF7-1）, Fusulinid grainstones （MF7-2）, Worn foraminiferal grain- stones （MF7-3）, Coated bioclastic grainstones （MF8）, Bahamite peloids grainstones （MF9-1）, Bioclastic-Bahamite peloids grainstones （MF9-2）, Ooid grainstones with radial ooids（ MF10-1 ）, Ooid grainstones with micritizatal concen- tric ooids （ MF10-2�
出处
《沉积学报》
CAS
CSCD
北大核心
2012年第5期834-846,共13页
Acta Sedimentologica Sinica
基金
国家973前期预研项目(编号2010CB434809)
国家自然科学基金项目(批准号:41072085
40902096)联合资助
关键词
微相组合
沉积环境
碳酸盐岩
上石炭统
江油—广元地区
microfacies combination
depositional environment
carbonates
the Upper Carboniferous
Jiangyou-Guangyuan area
Sichuan Province
