【摘要】：北黃海盆地X1和X2鉆井巖心揭示上侏羅統(tǒng)中有侵入的花崗質(zhì)巖石,鏡下鑒定其為花崗斑巖。對花崗斑巖進行了主量、微量和稀土元素測試分析,樣品的Si O2含量介于70.22%~71.88%之間,K2O/Na2O比值介于0.95~1.68之間,A/CNK比值介于0.75~1.12之間,有高鉀鈣堿性、弱堿質(zhì)-偏鋁質(zhì)性質(zhì)。微量元素組成富集Rb、Th、U等元素,相對虧損Nb、Eu、Sr等元素。稀土總量較高(∑REE=50.38×10-6~162.27×10-6),輕稀土(LREE)相對富集(LREE/HREE=6.86~25.43,(La/Yb)N=10.06~57.76),具有明顯的Eu負異常(?Eu=0.65~0.83)。樣品的Th含量高,與Rb呈正相關(guān)性,綜合主量元素特征(A/CNK1.1),判別其為I型花崗巖。LA-ICP-MS鋯石U-Pb測年結(jié)果表明X1井花崗斑巖年齡為110±1 Ma,X2井花崗斑巖年齡108±1 Ma、107±1 Ma,形成于早白堊世晚期。結(jié)合區(qū)域構(gòu)造背景及巖石地球化學特征認為,北黃海盆地花崗斑巖形成于板塊碰撞后的伸展構(gòu)造背景。
[Abstract]:The core of X1 and X2 drilling in northern Huang Hai basin reveals intrusive granitic rocks in Upper Jurassic, which are identified as granitic porphyry under microscope. The main amount, trace and rare earth elements of granitic porphyry were measured and analyzed. The results show that the content of Si O 2 is 71.88%, the ratio of K2O/Na2O is between 0.95 and 1.68, and the ratio of A/CNK is between 0.75 and 1.12. The trace elements are rich in Rb,Th,U and other elements, and are relatively depleted in elements such as Nb,Eu,Sr. The total amount of rare earth is relatively high (鈭，

本文編號：2265490