Thrust belt development in the central Apennines (Italy): Northward polarity of thrusting and out‐of‐sequence deformations in the Gran Sasso Chain
Thrust belt development in the central Apennines (Italy): Northward polarity of thrusting and out‐of‐sequence deformations in the Gran Sasso Chain
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亚平宁山脉中部逆冲带的发育（意大利）：格兰萨索链逆冲的北向极性和无序变形
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
L. Vezzani
中科院分区：
文献类型：
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作者：
F. Ghisetti;L. Vezzani
Lazio-Abruzzi碳酸盐岩台地位于意大利亚平宁山脉中部前陆褶皱和冲断带的最外层，沿一个弧形冲断前缘，由东西向向NNW-SSE方向摆动。格朗萨索逆冲断层的东西向、北缘断裂在其下盘切割了南北向、东缘的马尔切逆冲带和邻近的亚得里亚海前深的叠瓦岩。我们对格朗萨索叠瓦体系的野外测绘显示，有6条主要逆冲断层相互横切，这样，较高的逆冲断层斜向传播，穿过先前存在的逆冲片，导致早期叠瓦单元的重新逆冲，先前褶皱的断头，以及年轻层在旧层上的叠加。格朗萨索冲断带的变形主要发生在迈西旦—上新世中期，与马尔切冲断带的发育有一定程度的同步性，表明其缩短是由向北和向东扩展的冲断系统复杂结合的结果。沿格朗萨索逆冲锋面由西向东缩短，表明其沿南北向逆压右侧剪切带解耦，存在较大的微分逆时针旋转。这一机制可能是由Maiella前陆隆起引起的，Maiella前陆隆起是Lazio-Abruzzi碳酸盐岩台地堆积的支撑，并被迫逆时针旋转，导致逆序冲断传播缩短。
The Lazio-Abruzzi carbonate platform overrides the outermost sectors of the foreland fold and thrust belt of the central Apennines of Italy along an arcuate thrust front, which swings from E-W to NNW-SSE orientation. The E-W striking, north verging thrust faults of the Gran Sasso cut in their footwall the N-S oriented, east verging imbricates of the Marche thrust belt and the adjacent Adriatic foredeep. Our field mapping of the Gran Sasso imbricate system shows an array of six major thrust faults crosscutting each other in such a way that oblique propagation of higher thrust faults across the preexisting thrust sheets causes rethrusting of earlier imbricated units, decapitation of previous folds, and superposition of younger on older beds. Deformation in the Gran Sasso thrust belt mainly occurred between Messinian and middle Pliocene times and is partly synchronous with the development of the Marche thrust belt, thus implying that shortening resulted from a complex combination of northward and eastward propagating thrust systems. Increasing west to east shortening along the Gran Sasso thrust front indicates large, differential anticlockwise rotation by decoupling along a N-S transpressive right-lateral shear zone. This mechanism could have been induced by the Maiella foreland uplift, acting as a buttress against which the Lazio-Abruzzi carbonate platform was stacked and forced to rotate anticlockwise, with consequent shortening by out-of-sequence thrust propagation.