Cretaceous Propagation of the Eastern Sichuan Arcuate Fold‐Thrust Belt in Three Dimensions: Insights from AFT Analysis
Cretaceous Propagation of the Eastern Sichuan Arcuate Fold‐Thrust Belt in Three Dimensions: Insights from AFT Analysis
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DOI：
10.1002/cjg2.1726
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发表时间：
2012-05
期刊：
影响因子：
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通讯作者：
Ping Wang;Shaofeng Liu;Tangjun Gao;Kai Wang
中科院分区：
文献类型：
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作者：
Ping Wang;Shaofeng Liu;Tangjun Gao;Kai Wang
川东褶皱冲断带作为华南造山带的前缘，代表了华南造山带的最后一个挤压阶段，但其变形历史一直没有得到很好的约束。本文利用11个磷灰石裂变径迹（AFT）样品，包括7个新样品和4个已发表的样品，重建了川东褶皱冲断带的变形历史。样品采自褶皱冲断带三段的3个剖面：北方段3个，中段4个，南段4个。AFT热史模拟结果表明，快速冷却事件一般发生在135 ~ 65 Ma，反映了早白垩世至晚白垩世的构造变形。更重要的是，川东精确褶皱带的展布表现为三个向度：（1）平行于构造线的侧向展布。中段变形早于北方和南段。(2)垂直于结构线传播。褶皱变形在北方和中段向西传播，而在南段向东传播，这是因为华蓥山背斜变形较早。这一变形历史表明，川东褶皱带可能是由造山运动形成的，华蓥山断裂可能是作为先存断裂重新活动的。
As the frontal part of the South China orogen, the Eastern Sichuan fold-thrust belt represents the latest-stage of compression, but its deformational history has not been well constrained. In this paper, we use 11 apatite fission track (AFT) samples, including 7 new samples and 4 published samples, to reconstruct the deformational history of the Eastern Sichuan fold-thrust belt. The samples were collected from three profiles across three segments of the fold-thrust belt: 3 samples from the northern segment, 4 samples from the middle segment and 4 samples from the southern segment. The AFT thermal history modeling shows that the rapid cooling event generally occurred from 135 to 65 Ma, indicating the structural deformation during Early Cretaceous through Late Cretaceous. More importantly, the Eastern Sichuan accurate fold belt propagated in three dimensions: (1) Lateral propagation parallel to structural lines. The middle segment was deformed earlier than the northern and southern segments. (2) Propagation perpendicular to structural lines. The folding deformation propagated westward in the northern and middle segments, but eastward in the southern segment, because the Huayingshan anticline was deformed earlier than other folds. This deformational history suggests that the Eastern Sichuan fold belt might be orocline in origin and the Huayingshan fault might have been reactivated as pre-existing fault.