Altering Avalonia: oxygen isotopes and terrane distinction in the Appalachian peri-Gondwanan realmLaboratory for Stable Isotope Science (LSIS), The University of Western Ontario, Contribution 236.
Altering Avalonia: oxygen isotopes and terrane distinction in the Appalachian peri-Gondwanan realmLaboratory for Stable Isotope Science (LSIS), The University of Western Ontario, Contribution 236.
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改变阿瓦隆尼亚：阿巴拉契亚近冈瓦纳地区的氧同位素和地体区别稳定同位素科学实验室 (LSIS)，西安大略大学，贡献 236。
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
C. White
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作者：
J. Potter;F. Longstaffe;S. Barr;M. Thompson;C. White
阿巴拉契亚造山带北部阿瓦洛尼亚的620 ~ 550 Ma长英质火成岩中，绝大多数具有明显的18O衰竭特征。新元古代岩石δ18OWR值最低的是波士顿阿瓦隆地体（≥-3.1‰），其次是布雷顿角米拉地体和新不伦瑞克喀里多尼亚地体（≥-1.2‰）、纽芬兰阿瓦隆地体（≥+2.8‰）和新斯科舍省安提戈尼什高地（≥+5.3‰）。相比之下，在这些阿瓦洛纪地体中很少有古生代长英质火成岩中观察到这种18O的耗尽，在内部的甘德良地体中也很少有新元古代和古生代长英质火成岩。新元古代火成岩的低18o特征与200-450°C区域普遍的岩浆后蚀变有关，主要是由大气热液（δ18OH2O ~ -6‰~ -4‰）造成的。蚀变可能发生在新元古代晚期阿瓦洛尼亚张拉伸展时期。大尺度流体渗透与循环…
Distinct 18O depletion is characteristic of a large majority of the 620–550 Ma felsic igneous rocks of Avalonia in the northern Appalachian orogen. Neoproterozoic rocks in the Boston Avalon terrane have the lowest δ18OWR values (≥–3.1‰), followed by the Mira terrane in Cape Breton Island and the Caledonia terrane in New Brunswick (≥–1.2‰), the Avalon terrane in Newfoundland (≥+2.8‰), and the Antigonish Highlands in Nova Scotia (≥+5.3‰). In contrast, this depletion of 18O is observed in very few of the Paleozoic felsic igneous rocks from these Avalonian terranes, and also in very few of the Neoproterozoic and Paleozoic felsic igneous rocks from the inboard Ganderian terranes. The low-18O character of the Neoproterozoic igneous rocks is related to regional pervasive, post-magmatic alteration by predominantly meteoric-hydrothermal fluids (δ18OH2O ∼–6‰ to –4‰) at 200–450 °C. The alteration likely occurred during late Neoproterozoic transtensional extension of Avalonia. Large-scale fluid infiltration and circu...