内蒙古桌子山地区中奥陶统乌拉力克组砾屑灰岩特征及成因

Based on fieldwork, the causes of the calcirudite of the Wulalike formation of Middle Ordovician,in Zhuozi mountain area of Inner Mongolia was explored in the aspects of sedimentary background, lithology, structure and construction characteristics. Through the lithological, paleontology and geochemistry features of the Wulalike Formation, the sedimentary environment of Wulalike Formation is recognised as deep-water slope-basin environment. Wulalique calcirudite folder group sets of shale in bulk, internal unstratified, gravels mixed sizes, no separation, no grading, reflecting sedimentary characteristics of debris flow. During the Middle Ordovician, Helan aulacogen was strong rifting, in Helan aulacogen edge, carbonate gravity flow deposits were mainly controlled by synsedimentary fault. The Helan graben has the characteristics of strong The tectonic strength of the north Helan aulacogen was weak, while The tectonic strength of the north Helan aulacogen was strong. The tectonic strength of contemporaneous faults in the zhuozi mountain area was relatively weak, so the debris flow deposits in general was not very developed. Due to the steep slope, calcirudite mainly deposited on the foot of slope, and minority was transported to the basin edge, even in the basin. The calcirudite at the foot of slope owned large scale, large particles, rounded appearance, with section clear bottom; The calcirudite in the basin, as far away from the source area, were in small scale, small particles, with relatively better grinding and a flat bottom.