豫西栾川地区栾川群的层序、沉积环境及其构造古地理意义

运用构造分析与地层研究相结合的方法，修订了豫西栾川地区栾川群的地层层序，进而研究了栾川群的沉积环境及构造古地理特征。研究结果表明，栾川群主要为浅海一潮坪相的碳酸盐及碎屑泥质沉积，其中碎屑岩的成分和结构成熟度均较高，具有被动大陆边缘稳定型沉积特点。下栾川群沉积时期环境比较稳定，上栾川群反映沉积环境的动荡多变，可能为被动大陆边缘向主动大陆边缘转化的先期特征．

STRATIGRAPHIC SEQUENCE, SEDIMENTARY ENVIRONMENT AND ITS TECTONO-PALEOGEOGRAPHIC SIGNIFICANCE OF THE LUANCHUAN GROUP,LUANCHUAN AREA, HENAN PROVINCE

The authors discuss the stratigraphic sequence, sedimentary environment and tectonopalaeogeography of the Meso-Neoproterozoic Luanchuan Group,on the basis of the methodof tectonic analysis including primary and secondary structure and section surveying aswell as geologic mapping. The results show that the structural framework of Luanchuanarea is composed of two parts: the imbricate fan formed in Mesozoic (J-K) and the ductileshear deformation formed in Sinian to Early Palaeozoic. From these results,, the Luanchuan Group comprises six formations, from lower to upper: Baiyugou Formation, Xiangziping Formation, Baishugou Formation, Sanchuan Formation,, Nannihu Formation andMeiyaogou Formation. The data also indicate that the Luanchuan Group is a set of marineelastic-carbonate deposits formed in shallow sea-tidal environment. The clastic rocks, especially the sandstones have a high compositional and structural maturity. The carbonates include abundant stromatolites. All these represent a stable type of sediments formed in anancient passive continental margin.