张风雪^1,2,,
吴庆举^1,2,,
1. 中国地震局地球物理研究所, 北京 100081
2. 中国地震局地球物理研究所, 地震观测与地球物理成像重点实验室, 北京 100081

基金项目: 国家自然科学基金（41474074，41874072，41674103，41304066）资助


详细信息

作者简介: 张风雪, 男, 1984年生, 副研究员, 主要从事地震体波走时层析成像研究工作.E-mail:zhangfengxue336@163.com

通讯作者: 吴庆举, 男, 1966年生, 研究员, 主要从事地震学、地球内部结构以及地球动力学研究工作.E-mail:wuqj@cea-igp.ac.cn

中图分类号: P315

收稿日期:2018-12-04
修回日期:2019-03-31
上线日期:2019-08-05

Velocity structure in upper mantle and its implications for the volcanism nearby the north edge of Songliao Basin

ZHANG FengXue^1,2,,
WU QingJu^1,2,,
1. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
2. Key Laboratory of Seismic Observation and Geophysical Imaging, Institute of Geophysics, China Earthquake Administration, Beijing 100081, China


More Information

Corresponding author: WU QingJu,E-mail:wuqj@cea-igp.ac.cn

MSC: P315

--> Received Date: 04 December 2018
Revised Date: 31 March 2019
Available Online: 05 August 2019


摘要
摘要:中国东北是研究板内新生代火山活动及其成因的天然场所.以往的研究根据不同的壳幔速度结构，提出多种模型用以解释中国东北地区的火山活动.由于松辽盆地北缘的观测台站相对较少，导致这些模型对盆地北缘的约束较弱.我们利用近年来覆盖松辽盆地北缘的流动宽频带观测台站数据开展远震体波走时层析成像研究，获得了深达800 km的深部速度结构，在盆地北缘的火山群区域内得到如下认识：诺敏河和五大连池火山群共用一个200~300 km深处的地幔岩浆房.该地幔岩浆房内的低速异常为水平展布，未下延至地幔转换带内，并仅在该区域上地幔的局部范围内有所体现.结合前人的研究结果分析，我们认为该水平的局部低速异常可能是中生代晚期岩石圈拆沉导致的软流圈上涌热物质.
关键词: 诺敏河/
五大连池/
火山活动/
层析成像

Abstract:Northeast China is a natural experimental site for studying Cenozoic intraplate volcanism. On the basis of crustal and mantle velocity structures, several models for volcanism in this region have been proposed in previous studies. However, these models pose a weak constraint on the volcanism in north edge of Songliao Basin due to few seismic stations. We conducted a tomographic study using teleseismic body wave traveltime recorded by broadband seismic stations covering the north edge of Songliao Basin, and inverted the traveltime residuals to image crustal and mantle structure down to 800 km depth. Results show that the Nuomin River and Wudalianchi volcanic group share a common mantle magma chamber at 200~300 km depth beneath volcanic cones. The magma chamber shows a slow velocity anomaly in the horizontal direction, and only exists in a local area within the upper mantle that does not extend down to the mantle transition zone. Combined with previous work, we suggest that this horizontal low velocity structure resulted from asthenospheric upwelling triggered by lithospheric delamination during late Mesozoic.
Key words:Nuomin River/
Wudalianchi/
Volcanism/
Tomography



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