ANALYSIS OF VOLCANIC FACIES AND APPARATUS OF YINGCHENG FORMATION IN XUJAWEIZI FAULTING DEPRESSION,SONGLIAO BASIN NORTHEAST CHINA

Yingcheng formation in Xujaweizi faulting depression, Songliao Basin, is rich in volcanic rock. Based on core observation, thin sections identification and integration of well log and 2D/3D seismic data, 3 facies zones are identified in Yingcheng Formation in this basin, which is the eruption zone of volcanic, transitional zone and sedimentary zone. The eruption zone consists of lava, pyroclastic and limited sandy conglomerate. The transitional zone is characterized by interbedding of pyroclastic and sedimentary rocks,and a little volcanic lava rocks was also found in the strata. Sandy conglomerate, sandy stone and siltstone are developed in the sedimentary zone. Moreover, 8 types of volcanic lithofacies such as fallout facies, effusion facies, base surges facies, pyroclastics flow facies, lahar facies, eruption\|sedimentary facies, sub\|volcanic rock facis and sub\|explosive breccia facies, and three kinds of volcanic apparatus such as layered volcano, micro\|shield volcano and cone Volcano can be identified in the eruption zone. Analysis of volcanic lithofacies and apparatus are very important for both volcanism study and oil and gas exploration, because they are different from each other in that of features of volcanism, distribution of lithofacies and oil\|bearing.