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1979年野外工作期间,13位工作组成员研究了马更些山区中西部的五条地层剖面,为了重点研究加拿大的界限,选择了塞克威山图幅地区12号层中的一个临时界限区间,12号层是夹有页岩、粉砂岩和石英岩的前寒武纪晚期和早寒武世早期的沉积岩系的一部分,其上部主要由痕迹化石确定的时代。对早寒武世晚期的上覆岩层也进行了考察,这些岩层属塞克威组,在东面由地台型碳酸盐组成,在西面则相变为同期的斜坡和盆地沉积。三叶虫被用来作为对比这些较新地层的主要化石。
During the field work in 1979, 13 members of the Working Party studied five stratigraphic sections in the central and western Mawangshang Mountains. In order to focus on the boundaries of Canada, a temporary boundary section in the 12th layer of the Sekewei Shan area was selected, Layer 12 is a part of the Early Precambrian and Early Cambrian sedimentary rocks that contained shale, siltstone and quartzite, and the upper part of the 12th layer was dominated by trace fossils. Overlying stratigraphy was also examined during the late Early Cambrian period. These strata belong to the Sekewe Formation, which is composed of platform-type carbonates to the east and phase-changed slopes and basin deposits to the west. Trilobites are used as the main fossil to contrast these newer formations.