鄂东南早三叠世钙质风暴沉积特征及其初步研究
EARLY TRIASSIC CALCAREOUS STORM DEPOSITS IN SOUTHEASTERN HUBEI
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摘要: 鄂东南下三叠统地层发育齐全,野外露头连续,是大冶组的命名地(谢家荣,1924),长期以来受到地质学界的关注(图1)。在该地层中,发育多层砾屑灰岩,不同学者对其成因具有不同的解释,有的认为是一种泥皮成因的浅水标志;有的认为是深海盆地边缘或下部斜坡带的重力流沉积。根据我们近年来的研究,认为大部分砾屑灰岩应届风暴流、风暴重力流作用的产物。在野外露头上,风暴沉积现象清晰,风暴作用证据充分。Abstract: The storm current and storm gravity-flow deposits are well-developed in the Early Triassic strata in southeastern Hubei. In terms of the principles and methods of comparative sedimentology, the present paper deals in detail with the processes and mechanism for the storm deposition, erosional structures, sedimentary structures and sedimentary sequences, with stress on a new type of erosional sturctrue, i. e. tear-pull structure recognized in the calcareous storm deposits in the study area. The resulting transverse model for the storm deposits is proposed according to the zonation of the strom deposits, thus contributing a lot to the study of the Early Triassic palaeoclimates, palaeogeography and palaeoenvironments and to the chronostratigraphic classification and correlation in the study area.