Relationship between vitrinite reflectance of deformed coal and palaeotectonic stress field in western Henan coalfield

In order to study the influence of tectonic stress on coal vitrinite reflectance,taking the primary structure coal and the deformed coal from deferent tectonic areas in the coal fields of western Henan as the research objects,and using the method of oriented samples and reflectance measurement for contrast research,the article found that the reflectance of deformed coal is commonly higher than that of primary structure coal.According to the relation between vitrinite reflectance and tectonic stress,the palaeotectonic stress field of each tectonic area can be obtained.The correlation study of principle stress direction of multi-tectonic movements after coal accumulation indicates that the great tectonic movement affected the coal deformation and vitrinite reflectance of No.2₁ coal is gravity sliding structure induced by the early Xishan raise-slanting movement based on earlier faults in Songji tectonic area,but in Xiaoxiong tectonic area is a kind of the reverse thrust nappe structure generated during the later Yanshan movement.