【摘要】：內蒙古海拉爾北部八大關地區(qū)花崗巖以正長花崗巖和二長花崗巖為主,鋯石U-Pb定年顯示其形成于晚三疊世((212±1.7)~(226.7±1.6)Ma)。巖石為弱過鋁質(A/CNK=1.01~1.10),分異指數(shù)(DI)介于92.5~95.8之間。巖石大離子親石元素K和Rb以及LREE相對富集,高場強元素Nb、Ta、P、Ti和Ba、Sr相對虧損,并顯示中等銪負異常(δEu=0.51~0.71)。較低的10 000 Ga/Al值(平均1.91)以及較低的鋯石飽和溫度(平均683℃)等特征顯示該花崗巖屬于高分異Ⅰ型。鋯石的εHf(t)值較高(4.50~10.45),Hf二階段模式年齡為0.59~0.97 Ga,反映其源區(qū)物質為新元古代增生的基性地殼。綜合區(qū)域其他地質研究成果,認為研究區(qū)晚三疊世花崗巖形成于蒙古—鄂霍茨克洋板塊俯沖的活動大陸邊緣環(huán)境。
[Abstract]:The granites in Badaguan area, northern Hailaer, Inner Mongolia are dominated by syenite and monzomorphic granites. Zircon U-Pb dating indicates that they were formed in the late Triassic (212 鹵1.7) ~ (226.7 鹵1.6) Ma). The rock is weak peraluminous (A/CNK=1.01~1.10) and its differentiation index (DI) is between 92.5 and 95.8. Large ion lithophile elements K, Rb and LREE are relatively enriched, and high field strength elements Nb,Ta,P,Ti and Ba,Sr are relatively depleted, showing moderate europium negative anomaly (未 Eu=0.51~0.71). The lower Ga/Al value of 10 000 (average 1. 91) and the lower zircon saturation temperature (mean 6 83 鈩，

本文編號：2399911