Lithosphere structure and thickness beneath the North China Craton from joint inversion of ambient noise and surface wave tomography
Lithosphere structure and thickness beneath the North China Craton from joint inversion of ambient noise and surface wave tomography
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DOI：
10.1002/jgrb.50191
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发表时间：
2013-05
期刊：
影响因子：
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通讯作者：
Youcai Tang;Y. Chen;Shiyong Zhou;J. Ning;Z. Ding
中科院分区：
文献类型：
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作者：
Youcai Tang;Y. Chen;Shiyong Zhou;J. Ning;Z. Ding
通过对周期为6~143个S的瑞雷波相速度的反演，获得了北中国克拉通详细的地壳和上地幔三维地震结构。相速度由环境噪声和远震面波层析成像得到，然后由相速度反演成S波速度。结果表明，华北盆地和鄂尔多斯地块的地壳速度和莫霍面深度都有明显的快速变化。华北盆地地壳较薄(31~34公里)，速度较低；鄂尔多斯地块地壳较厚(~40公里)，速度较高。我们还利用一个简单的S波速/温度关系，从反演的S波速估算了岩石圈厚度。华北盆地成像为上地幔极薄岩石圈(~65 km)的S波速低异常，鄂尔多斯地块为高S波速异常，岩石圈较厚(~gt；120 km)。这些结果表明，华北盆地和鄂尔多斯地块具有不同的热和(或)化学性质，自新生代以来经历了不同的地幔过程和演化历史。此外，在北部与鄂尔多斯地块交界的河套裂谷和南部与鄂尔多斯地块交界的渭河裂谷之下，还分别发现了缓慢的S波速度和很薄的岩石圈(~65公里)。然而，作为华北盆地和鄂尔多斯地块交界处的山西裂谷，其岩石圈要比河套和渭河裂谷厚得多，速度也高得多。
We imaged detailed 3‐D crustal and uppermost mantle seismic structures in the North China Craton from inversion of Rayleigh wave phase velocity at periods of 6 to 143 s. The phase velocities were obtained from a combination of ambient noise and teleseismic surface wave tomography, and then the phase velocities were inverted to S‐wave velocities. The results show that both the Huabei Basin and Ordos Block have markedly rapid variations in both crustal velocities and the Moho depth. Huabei Basin has a thin (31–34 km) crust with low velocities while Ordos Block has a thick (~40 km) crust with high velocities. We also estimated the lithospheric thickness from the inverted S‐wave velocities using a simple S‐wave velocity/temperature relationship. Huabei Basin was imaged as a low S‐wave‐velocity anomaly in the uppermost mantle with very thin lithosphere (~65 km), while Ordos Block was revealed as a high S‐wave‐velocity anomaly with rather thick lithosphere (>120 km). These results indicated that Huabei Basin and Ordos Block have different thermal and/or chemical properties and had experienced different mantle processes and evolution histories since the Cenozoic. Furthermore, slow S‐wave velocities and very thin lithosphere (~65 km) were also found beneath Hetao and Weihe rifts bounding Ordos Block at north and south, respectively. However, Shanxi Rift—the boundary between Huabei Basin and Ordos Block—had a much thicker and higher velocity lithosphere than Hetao and Weihe rifts.