【摘要】：位于小興安嶺—張廣才嶺構(gòu)造帶北段的東安粗粒和細粒堿長花崗巖,經(jīng)本文測定,其鋯石LA-ICPMS U-Pb年齡分別為174Ma和184~175Ma。堿長花崗巖都為高Si O2、高堿、低TFe O、Mg#、Ca O的高鉀鈣堿性系列,具有I型和A型花崗巖過渡性質(zhì)。都表現(xiàn)為輕稀土富集重稀土虧損,而且重稀土分異較大,細粒鉀長花崗巖(∑REE=76.98~109.53,δEu:0.33~0.70)較粗粒堿長花崗巖(∑REE=95.49~140.00,δEu:0.70~0.94)輕重稀土分餾明顯,稀土總量偏低,具有更大的銪負異常;與原始地幔相比,堿長花崗巖都相對富集輕稀土元素(Le、Ce)、大離子親石元素LILE(Rb、Th、U、K),虧損高場強元素HFSE(Nb、Ta、Ti、P、Y、Yb、Lu),還相對虧損Ba、Sr、Eu,相對富集Zr、Hf,都與大陸緣弧巖漿具有相似性。而細粒堿長花崗巖高場強元素(Zr、Hf、Eu、Ti、Y、Yb、Lu)較粗粒堿長花崗巖分異程度大;根據(jù)Pb、Hf同位素和Nb/Ta、Zr/Hf比值等,堿長花崗巖主要起源于中基性殼源熔融,相對比,粗粒堿長花崗巖原巖含有較多幔源組分,細粒堿長花崗巖主要為殼源組分;粗粒和細粒堿長花崗巖形成于牡丹江洋閉合、松嫩地塊與佳木斯地塊晚造山擠壓后的伸展環(huán)境,明顯區(qū)別于小興安嶺—張廣才嶺鉬、鉛—鋅多金屬形成的碰撞造山(同造山)環(huán)境;小興安嶺—張廣才嶺鉬、鉛—鋅多金屬礦床主要受控于牡丹江大斷裂,具有呈近南北向帶狀展布的分布規(guī)律。
[Abstract]:The Dongan coarse grain and fine grained alkali feldspar granites located in the northern segment of the Xiaoxinganling Zhangguangcailing tectonic belt are determined in this paper. The zircon LA-ICPMS U-Pb ages are 174Ma and 1844 Ma respectively. The alkali feldspar granites are all high Si O 2, high alkali, low TFe O mg #Ca O high potassium calc-alkaline series, which have the transition properties of I-type and A-type granites. All of them are characterized by light rare earth enrichment and heavy rare earth depletion, and the differentiation of heavy rare earth is larger, and the 鈭，

本文編號：2371387