Mechanisms of Archean crust formation inferred from high-precision HFSE systematics in TTGs
Mechanisms of Archean crust formation inferred from high-precision HFSE systematics in TTGs
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DOI：
10.1016/j.gca.2011.04.027
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发表时间：
2011-08-01
影响因子：
5
通讯作者：
Svahnberg, Henrik
中科院分区：
文献类型：
--
作者：
Hoffmann, J. Elis;Muenker, Carsten;Svahnberg, Henrik
太古宙英云闪长-奥长-花岗闪长质岩浆是镁铁质地壳在高压下熔融形成的。TTG的残留矿物学（无论是（石榴石）角闪岩或含金红石榴辉岩）被认为是控制微量元素的预算TTG。特别是，高场强元素（HFSE）的比率可以帮助区分不同的残留岩性。为了对TTG的源矿物学进行约束，我们通过同位素稀释（Nb，Ta，Zr，Hf）以及Lu-Hf和Sm-Nd测量对代表性的，ca.西格陵兰南部、西印度和上级省的3.85-2.8 Ga TTG和相关岩石类型。这些测量得到了TTG主要和微量元素数据的补充。质地均匀的早太古代（3.85-3.60 Ga）和中太古代（约3.85-3.60 Ga）3.1-2.8 Ga old）TTG具有低Ni（
It has been proposed that Archean tonalitic-trondhjemitic-granodioritic magmas (TTGs) formed by melting of mafic crust at high pressures. The residual mineralogy of the TTGs (either (garnet)-amphibolite or rutile-bearing eclogite) is believed to control the trace element budget of TTGs. In particular, ratios of high-field-strength elements (HFSE) can help to discriminate between the different residual lithologies. In order to place constraints on the source mineralogy of TTGs, we performed high-precision HFSE measurements by isotope dilution (Nb, Ta, Zr, Hf) together with Lu-Hf and Sm-Nd measurements on representative, ca. 3.85-2.8 Ga TTGs and related rock types from southern West Greenland, W-India and from the Superior Province. These measurements are complemented by major and trace element data for the TTGs. Texturally homogeneous early Archean (3.85-3.60 Ga old) and Mesoarchean (ca. 3.1-2.8 Ga old) TTGs have both low Ni (