Thermal history of the 3.5–3.2 Ga Onverwacht and Fig Tree Groups, Barberton greenstone belt, South Africa, inferred by Raman microspectroscopy of carbonaceous material
Thermal history of the 3.5–3.2 Ga Onverwacht and Fig Tree Groups, Barberton greenstone belt, South Africa, inferred by Raman microspectroscopy of carbonaceous material
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南非巴伯顿绿岩带 3.5–3.2 Ga Onverwacht 和无花果树群的热史，通过碳质材料拉曼显微光谱推断
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
D. Lowe
中科院分区：
文献类型：
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作者：
M. Tice;B. Bostick;D. Lowe
碳质材料的拉曼光谱是从巴伯顿绿岩带中部 Onverwacht 和无花果树群的燧石样品中现场收集的。该光谱具有无序碳特征的两个主峰：1310 cm 21 处的D峰和1580-1600 cm 21 处的O峰。 D峰位置和相对峰强度和面积表明所有样品都已改变为较低的绿片岩相或以上。最高温度与地层位置或热液蚀变程度之间没有观察到相关性，这意味着巴伯顿绿岩带中部的变质作用是区域性的，不伴随大量热液的流动。来自西澳大利亚州皮尔巴拉区块的 Marble Bar Chert 样品的加热程度与来自 Barberton 的样品相同。这项研究展示了碳质材料拉曼光谱作为低温变质相敏感地温计的用途。该应用程序还可用于确定变质地体中推定微化石的古老性。
Raman spectra of carbonaceous material were collected in situ from samples of cherts of the Onverwacht and Fig Tree Groups in the central Barberton greenstone belt. The spectra feature two dominant peaks characteristic of disordered carbon: the D peak at ;1310 cm 21 and the O peak at 1580-1600 cm 21 . D peak positions and relative peak intensities and areas indicate that all samples have been altered to lower greenschist facies or above. No correlation was observed between maximum temperature and stratigraphic position or degree of hydrothermal alteration, implying that metamorphism in the central Barberton greenstone belt was regional and unaccompanied by the flow of large quantities of hydrothermal fluids. Samples from the Marble Bar Chert of the Pilbara block, Western Australia, have been heated to the same extent as samples from Barberton. This study demonstrates the use of Raman spectra of carbonaceous material as a sensitive geother- mometer for low-temperature metamorphic facies. This application could also be used to establish the antiquity of putative microfossils from metamorphic terranes.