Imbricated ocean-plate stratigraphy and U-Pb zircon ages from tuff beds in cherts in the Ballantrae complex, SW Scotland
Imbricated ocean-plate stratigraphy and U-Pb zircon ages from tuff beds in cherts in the Ballantrae complex, SW Scotland
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DOI：
10.1130/b26329.1
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发表时间：
2010-03
影响因子：
4.9
通讯作者：
Y. Sawaki;T. Shibuya;T. Kawai;T. Komiya;S. Omori;T. Iizuka;T. Hirata;B. Windley;S. Maruyama
中科院分区：
文献类型：
--
作者：
Y. Sawaki;T. Shibuya;T. Kawai;T. Komiya;S. Omori;T. Iizuka;T. Hirata;B. Windley;S. Maruyama
Ballantrae杂岩中Balcreuchan群的大洋板块地层（玄武岩、燧石、碎屑岩）被平行层逆冲断层重复，在Ballantrae以北约5 km的Bennane Head以南形成双重结构。五个凝灰岩层，都在硅质岩，具有相似的U-Pb锆石年龄约。470 ± 10 Ma。双岩体的几何极性和锆石年龄为巴兰特拉杂岩增生楔的构造演化提供了新的制约。该复式构造的西北向逆冲表明俯冲作用是从西北向东南方向的，而主蛇绿岩体前缘的这种极性与Ballantrae杂岩的火山弧岩向北的逆冲一致。
Ocean-plate stratigraphy (basalt, chert, clastics) of the Balcreuchan Group in the Ballantrae complex is repeated by layer-parallel thrusts to form duplex structures south of Bennane Head, ~5 km north of Ballantrae. Five tuff beds, all in chert, have similar U-Pb zircon ages of ca. 470 ± 10 Ma. The geometrical polarity of the duplexes and the zircon ages provide new constraints on the tectonic evolution of the accretionary wedge of the Ballantrae complex. Northwestward thrusting of the duplexes suggests that subduction was from the northwest to the southeast, and this polarity at the leading edge of the main ophiolite body is consistent with the northward younging of the volcanic arc rocks of the Ballantrae complex.