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对赣南上犹县侵入于陡水加里东期花岗岩的煌斑岩的地球化学进行了分析,并重点分析了其中锆石的U-Pb年龄和Hf同位素组成.岩石学和地球化学特征显示陡水煌斑岩属于高钾弱碱性辉云煌斑岩,高Mg#(0.74),Ni(253μg/g),Cr(893μg/g),但又富REE,Rb,Sr,Ba和K等不相容元素表明其母岩浆可能起源于被非壳源介质交代过的富集地幔.形貌学和LAM-ICPMSU-Pb定年显示煌斑岩中的锆石都是捕获的,大多数形成于古元古代晚期1.86Ga,少量形成于显生宙的不同时期.古元古代锆石具有岩浆成因特征并具有相似的176Hf/177Hf和176Lu/177Hf同位素比值,表明它们来源于同一火成岩基底.该基底年龄和Hf同位素组成相似于浙南龙泉地区古元古代花岗岩,而不同于南岭地区的基底组成,说明研究区属于东华夏武夷地块的古元古代基底向西延伸的一部分.这些古元古代锆石具有低的Hf同位素组成,显示壳源特征.Hf模式年龄,以及老的继承核的存在和结合前人的资料,表明古元古代岩浆活动的源岩是新太古代地壳,暗示武夷地块存在更老的基底.古元古代克拉通化后,武夷地块一直稳定达1.0Ga以上.5颗显生宙锆石的U-Pb年龄和Hf组成表明研究区深部的古元古代基底在加里东期、印支期和燕山早期受到了多期岩浆活动的改造,而且在加里东时期的岩浆活动还可能伴有新生地壳的再造.
The geochemistry of the lamprophyre intruded into the steep water Caledonian granite in Shangyou County, southern Jiangxi Province is analyzed and the U-Pb ages and Hf isotopic compositions of the zircons are analyzed. The petrological and geochemical characteristics show a steep The water-light porphyry belongs to the high-k, weak-alkaline himalayan lamprophyres with high contents of Mg # (0.74), Ni (253μg / g) and Cr (893μg / g) but rich REE, Rb, Sr, Ba and K Incompatible elements indicate that their parent magma may have originated from enriched mantle that was replaced by non-crustal source media.Morphology and LAM-ICPMSU-Pb dating show that all the zircons in the lamprophyre are trapped, most of them formed in In the late Paleoproterozoic, 1.86Ga was formed in small quantities in Phanerozoic.The Paleoproterozoic zircons have magmatic genetic characteristics and similar 176Hf / 177Hf and 176Lu / 177Hf isotopic ratios, indicating that they originated from the same igneous basement. The age and Hf isotopic composition are similar to those of the Paleoproterozoic granite in the Longquan area of southern Zhejiang and different from the basement composition of the Nanling area, indicating that the study area belongs to the westward extension of the Paleoproterozoic basement of the Wuhua massif in East China. Zircons have a low Hf isotopic composition, showing shell-source characteristics Age, and the existence of the old inherited nucleus, combined with the data of the predecessors, indicate that the source rocks of the Paleoproterozoic magmatism are the Neoarchean crust, suggesting that the Wuyi block has an older basement. After the ancient Paleo-karatonghua, Wuyi The block has been stable above 1.0Ga. The U-Pb ages and Hf compositions of the five Phanerozoic zircons indicate that the Paleoproterozoic basement in the deep part of the study area was subjected to multi-stage magmatic activities in the early Caledonian, Indosinian and Yanshanian Alteration, and magmatic activity during the Caledonian period may also be accompanied by the rebuilding of new crusts.