从露头剖面层序中求解海平面变化

RECONSTRUCTION OF SEA-LEVEL CURVES BASED ON OUTCROP SEQUENCES

关键词:  海平面变化  相对水深变化  露头剖面  塔里木盆地北部  寒武纪

Key words:  sea-level change  relative change in water depth  outcrop sequence  northern Tarim Basin Cambrian

摘要:

海平面变化规律是层序地层学研究核心内容之一。在露头剖面的沉积学研究中,通常只能对水深变化作出估价,而难以直接判断海平面的变化情况。因此,如何从露头剖面的地层层序中来求解海平面的变化,是撄在我们面前的一个难题。本文介绍了用数学方法和改进后的Fischer图解来求解在特定沉积背景下形成的地层层序所反映的海平面变化情况,并用上述方法对塔里木盆地北部肖尔布拉克地区寒武纪露头剖面进行了海平面变化的重建,得到了良好的结果。

Abstract:

The regularity of sea-level changes is one of the most important aspects of sequence stratigraphy.Usually,only the relative changes in water depth can be assessed;the sea-lev-el changes are difficult to be understood directly from the study of outcrop sequences.So how to extract the information of sea-level changes from the outcrop sequences becomes a very difficult problem confronting us.The methods of mathematics and developed Fischer Plots have been introduced in this paper to reconstruct the sea-level changes based on the stratigraphic sequences deposited in the shallow peritidal environments.The sea-level changes in the Cambrian strata in the Xiao'erbulake region of northern Tarim Basin have been reconstructed with the aid of these methods,and the results are satisfactory.