Complicated Crustal Structure Beneath Northeast China Revealed by Receiver Function Analyses

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

Northeast China locates between the Siberian Craton and the North China Craton. Complicated but episodic evolution shapes the basic geological settings in present NE China. Based on our broadband NECsaids Array stations’ records from July 2010 to June 2017, as well as CEA permanent stations’ records from July 2008 to June 2017 and NECESSArray records from September 2009 to August 2011, we acquired 33752 P-wave receiver functions in total with high quality. And then using H-κ and CCP stacking techniques, we obtained the highest-resolution crustal structure in central-south part of NE China, which consists of 231 measurements of crustal thickness and Vp/Vs ratio (including 89 measurements from former studies) and 3 CCP stacking profiles. The five micro-continental blocks in our study region show different crustal structure distinctly. The south-central part of the Zhangguangcai Ranges owns the similar crustal thickness and Vp/Vs ratio as the northeastern part of the North China Craton. The southeastern part of the Songliao Block has the thinnest crust and highest crustal Vp/Vs ratio. As for the western Khanka Block, it keeps a slightly thicker crustal thickness while with the lowest crustal Vp/Vs ratio. The southwestern part of the Jiamusi Massif owns an ordinary crustal Vp/Vs ratio but its crust is the thickest. The northern segment of the Tanlu Fault Zone appears to have different crustal structure in its northern and southern parts, though its Moho interface has been cut across along the whole fault zone. For its northern part (44.4°N-47°N), the Moho interface between the two main branches appears to drop down. While for the southern part (41.5°N-43.3°N), the Moho interface changes into being uplifted under the fault zone. Around the Changbaishan Tianchi volcano, the Moho interface under the caldera subsides and the measurements at 3 stations with high Vp/Vs ratio located at the north and east of the caldera within 10 km may indicate the present crustal magma.

Presenting Author: Qi-Fu Chen

Authors