The Highland Border Ophiolite of Scotland: observations from the Highland Workshop field excursion of April 2008
The Highland Border Ophiolite of Scotland: observations from the Highland Workshop field excursion of April 2008
复制标题
苏格兰高地边界蛇绿岩：2008 年 4 月高地研讨会实地考察的观察结果
DOI：
10.1144/0036-9276/01-381
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发表时间：
2009
影响因子：
0.7
通讯作者：
R. Strachan
中科院分区：
文献类型：
--
作者：
W. G. Henderson;P. Tanner;R. Strachan
2008年4月，高地讲习班的23名与会者访问了阿伯福伊尔和布特岛之间的苏格兰高地边境综合体的关键地点。碎片蛇纹碳酸盐的广泛存在得到了证实，至少有一些可能是在洋-陆过渡环境中形成的断层泥，类似于利古里亚型伸展大陆-洋边缘的蛇纹岩。一致的观点是，洛赫阿德和布特的斜长角闪岩似乎没有比绿帘石-斜长角闪岩相更高的变质等级。此外，“花岗岩类岩石”的狭窄区域和与蛇绿岩接触的Dalradian岩石中的斑点可能代表相对较低的Barrovian区域变质温度效应，而不是仰冲蛇绿岩底部接触变质的证据。最后，高地边界蛇绿岩似乎最初覆盖在南部高地群和特罗萨克斯群之上，并被D4下弯反形带旋转。没有证据表明，在这些地方，以支持这一假设，即高地边境复杂的bridges到西北或没有经历格兰扁变形事件。
Synopsis In April 2008, 23 attendees of the Highland Workshop visited critical localities of the Scottish Highland Border Complex between Aberfoyle and the Isle of Bute. Widespread existence of fragmental ophicarbonates was confirmed, with the possibility that at least some may have formed as fault gouges in an ocean–continent transition environment similar to those reported from serpentinites in Ligurian-type extensional continent–ocean margins. The consensus view was that amphibolites at Loch Ard and on Bute appear to have been at no higher metamorphic grade than epidote-amphibolite facies. Also that, narrow zones of ‘granitoid rocks’ and spotting in Dalradian rocks in contact with ophicarbonate rocks could represent relatively low Barrovian regional metamorphic temperature effects rather than evidence for contact metamorphism in the sole of an obducted ophiolite. Finally, the Highland Border Ophiolite appears to have originally overlain the Southern Highland and Trossachs groups and was rotated with them by the D4 Downbend Antiform. No evidence was seen at these localities to support the hypothesis that the Highland Border Complex youngs to the NW or did not undergo Grampian deformational events.