Geologic significance of the palaeolatitudinal change and the character of connate water in Late Triassic of Ordos Basin

Abstract:

This study presents the palaeolatitudinal change and the character of connate water in Late Triassic of Ordos Basin. The results show that palaeolatitude of Ordos ancient lake-basin in Late Triassic was 31.03ON，it was 4O more than the present latitude. So we can presume the climate of Late Triassic was mildness and humidity,creature got flouring, and organic substance were rich ,which could generated oil source rock of abundant organic substance. Utilizing outcome of test about B、Sr、Ba element in mudstone ,and contrast it with element geochemistry index , Ordos Basin from Ch8 to Ch6 period was freshwater lake basin .The wate area and deepness of lake-basin had experienced course of shrinkage-spread- shrinkage during Ch8 ,Ch7 and Ch6,which constituted reservoir-oil source rock- cap rock in lognitudinal.It is important significance about prospect for oil-gas in Ordos Basin when late Triassic.