鄂尔多斯盆地南缘早古生代碳酸盐岩高频沉积旋回分析

鄂尔多斯盆地南缘早古生代碳酸盐岩台地的演化可分低能和高级缓坡、具局限性内陆架盆地的镶边陆架、虎蒸发性内陆架盆地的镶边陆架及断边缘４个阶段，在不同的演化 ，高频沉回旋类型具有明显差异，说明沉积背景控制了碳酸盐岩高频沉积旋回的复杂性、多样性、根据对和线个演经阶段高频旋回的分级栩比及周期计算表明，其驱动机制应与米兰科维奇的天文轨道有关。

FISCHER PLOT OF CAMBRIAN AND ITS SIGNIFICANCES IN FENGHUANG, HUNAN

Fenghuang in Hunan Province was an outer shelf in Early Cambrian and platform-edge slope in Middle and Late Cambrian. Sea level fluctuation curve obtained from Fischer plot which is corrected shows the tendency of global sea level rising and consistent enlarging of accommodation in Cambrian. This shows a coincident relationship with the evolution of trilobita. Because of rich regional trilobita and obvious bioarea, trilobita zone can't be correlated to intercontinents in Early Cambrian, except for in Late Cambrian. Two important transgression planes (536Ma and 517.2Ma) are the best demarcation lines between series. Maximum seaflooding period may be confirmed by comparing with R 2 curve in North American between 515Ma and 517Ma (Changshan Age). Generally, the range of global sea level fluctuation isn't large, 140m in this area, 400m at maximum in House Mountains, 50m at minimum in Virginia-Tennessee area. Global sea level fluctuation curve in Cambrian isn't still well-considered because of the influences of many factors.