Paleoproterozoic basement beneath the southern Jiangxi Province:Evidence from U-Pb ages and Lu-Hf isotopes in zircons from the Doushui lamprophyre

这篇论文论述侵入的煌斑岩的 geochemical 分析在 Shangyou 县的古苏格兰的 Doushui 花岗石身体，南部的江西省。U-Pb 标明日期和 Hf 同位素分析特别从它为锆石被执行。Petrological 和 geochemical 特征证明煌斑岩属于 high-K，弱碱的辉石黑云母煌斑岩。它被 Mg #(0.74 ) ， Ni (253 μg/g ) 和 Cr (893 μg/g ) 满足的高度描绘，并且也在不兼容的元素充实，例如 REE， Rb， Sr， Ba 和 K。它的原语融化，这被建议可能由 non-crust-derived 源于充实的披风 metasomatized 代理人。在煌斑岩标明日期锆石的结果的形态学和 LAM-ICPMS 显示他们是从深外壳的岩石捕获的 xenocrysts。在 ∼1.86 Ga 形成的大多数 xenocrystic 锆石，和在不同 Phanerozoic 时期的一些。Paleoproterozoic 锆石具有 magmatic 起源并且有类似的 176Hf/177 Hf 和 176Lu/177 Hf 比率，显示他们可能从一样的火的地下室岩石。年龄和从这地下室岩石的锆石的 Hf 同位素作文类似于在南部的浙江省的 Paleoproterozoic Danzhu 花岗石的那些，但是极其与 Nanling 地下室区分开来，建议学习区域可能是一向西在东方卡赛西亚·布洛克的 Paleoproterozoic Wuyishan 岩层的延期部分。这些 Paleoproterozoic 锆石有低 Hf 同位素作文，外壳的来源特征。这些锆石的 Hf 模型年龄和在他们以内的更旧的继承核心的存在，结合了可得到的其它数据由以前的研究报导了，建议 Paleoproterozoic 岩浆的来源是 Neoarchaean 外壳，在 Wuyishan 岩层暗示更旧的地下室的存在。U-Pb 年龄和五 Phanerozoic 锆石的 Hf 同位素显示那个 Paleoproterozoic 地下室经历了多重做的发生在古苏格兰， Indosinian 和早 Yanshanian 分别地。古苏格兰的 magmatism 也涉及少年外壳重做。

This paper presents geochemical analyses of a lamprophyre intruding the Caledonian Doushui granite body in Shangyou County, southern Jiangxi Province. U-Pb dating and Hf-isotope analyses are especially carried out for zircons from it. Petrological and geochemical features show that the lamprophyre belongs to a high-K, weakly alkaline pyroxene-biotite lamprophyre. It is characterized by high Mg^# （0.74）, Ni （253 μg/g） and Cr （893 μg/g） contents, and also enriched in incompatible elements, such as REE, Rb, Sr, Ba and K. It is suggested that its primitive melt probably derived from enriched mantle metasomatized by non-crust-derived agent. Morphology and LAM-ICPMS dating results of zircons in the lamprophyre indicate that they are xenocrysts captured from deep crustal rocks. Most xenocrystic zircons formed at -1.86 Ga, and a few in different Phanerozoic periods. The Paleoproterozoic zircons are of magmatic origin and have similar ^176Hf/^177Hf and ^176Lu/^177Hf ratios, indicating that they probably are from the same igneous basement rock. The ages and Hf-isotope compositions of zircons from this basement rock are similar to those of Paleoproterozoic Danzhu granite in the southern Zhejiang Province, but extremely distinguished from the Nanling basement, suggesting that the study area probably is a westward extension part of Paleoproterozoic Wuyishan terrane in the eastern Cathaysia Block. These Paleoproterozoic zircons have low Hf-isotope compositions, characteristic of crustal source. Hf model ages of these zircons and the presence of older inherited cores within them, coupled with available other data reported by previous studies, suggest that the source of Paleoproterozoic magma is Neoarchaean crust, implying the existence of older basement in the Wuyishan terrane. U-Pb ages and Hf isotopes of five Phanerozoic zircons indicate that Paleoproterozoic basement underwent multi-reworking occurring in Caledonian, Indosinian and early Yanshanian, respectively. The Caledonian magmatism also involves reworking of juvenile crust.