Abstract:

This paper deals with the colour alteration of Permian and Triassic
conodonts in Guizhou Province.According to the sequence of the colour
alteration index of conodonts，it can be divided into several grades of CAI
from 1.5 to 5.The distribution of CAI isograde lines of Upper Permian
and Lower 'Triassic in the CAI isograde maps shows a"X"shape (see Fig.
12)，and m ay be divided into four different CAI value areas.These area
correspond to the to w or high value areas of the vitrinite reflectance
respectively.(See Fig.3)"This paper discusses the calculation of paleogeotem perature，paleogeother-mal gradient and primitive depth of burial by means of CAI.It is thought that the result of calculation of tem perature is a little lower，but can be corrected according to the corresponding relation betwxen the colour alteration index and the vitrinite reflectance.
The field data and the result of calculation show that the medium or
high CAI value area is directly related to the larger primitive depth
of burial and the higher paleogeotherm al gradient，and the low CAI value
area to the less primitive depth of burial and the lower paleogeothermal
gradient.This paper also discusse、tie corresponding relation between CAI valueand hydrocarbon occurrence.