發(fā)布時(shí)間：2018-05-25 09:23

  本文選題：骨頭崖花崗巖 + U-Pb定年��； 參考：《地質(zhì)論評(píng)》2017年06期

【摘要】：骨頭崖花崗巖位于北秦嶺構(gòu)造帶東部,西峽縣北部,對(duì)其開(kāi)展巖石成因研究有助于深入認(rèn)識(shí)燕山期北秦嶺豫西南段深部構(gòu)造演化。巖體定年樣品(GTY01)為中粒斑狀黑云母二長(zhǎng)花崗巖,30個(gè)鋯石測(cè)點(diǎn)中有25個(gè)測(cè)點(diǎn)的U-Pb同位素測(cè)定值位于或者接近~(207)Pb/~(235)U ~(206)Pb/~(238)U一致線,23個(gè)測(cè)點(diǎn)的~(206)Pb/~(238)U年齡介于108.4±0.9Ma~114.3±1.0Ma之間,其加權(quán)平均年齡為111.7±0.6Ma(MSWD=1.4),代表了骨頭崖花崗巖的形成時(shí)代。鋯石稀土元素具有輕稀土虧損、重稀土富集、Ce正異常及負(fù)Eu異常的特征,形成溫度介于626℃~769℃之間,巖體的鋯石/熔體中重稀土元素特征表明,其形成過(guò)程中經(jīng)歷了巖漿混合作用。骨頭崖花崗巖為富硅、堿和貧鈣、鎂的高鉀鈣堿性系列。巖體富集Rb、Th和虧損Nb、Ta、Ti。巖體的稀土配分模式具有右傾、輕稀土富集、重稀土虧損和負(fù)Eu異常的特征,(Eu值介于0.48~0.60之間,(La/Yb)_N范圍為5.82~11.19,源區(qū)組成和部分熔融程度控制了骨頭崖花崗巖的成分變異。骨頭崖花崗巖形成于厚度為~40km的地殼內(nèi),其部分熔融源區(qū)為角閃巖相,部分熔融殘余相主要為角閃石和斜長(zhǎng)石。骨頭崖花崗巖是巖石圈拆沉作用所觸發(fā)的巖漿底侵作用的產(chǎn)物,從源區(qū)巖石部分熔融到最終上侵固結(jié)成巖耗時(shí)~15Ma,它是巖石圈拆沉作用滯后的巖漿響應(yīng)。
[Abstract]:The Jiaoya granite is located in the east of the North Qinling tectonic belt and the north of Xixia County. The study of its petrogenesis is helpful to further understand the deep tectonic evolution of the southern segment of the North Qinling Mountains in the Yanshanian period. The U-Pb isotopic values of 25 of the 30 zircon sites are located in or close to the 235U / 235U / 238U consistent line, and the age of 238U is between 108.4 鹵0.9Ma~114.3 鹵1.0Ma for 23 of the 30 zircon sites, and the age of 238U is 108.4 鹵0.9Ma~114.3 鹵1.0Ma for 23 of the 30 zircon sites, and the U-Pb isotopic values of 25 of the 30 zircon sites are in the range of 108.4 鹵0.9Ma~114.3 鹵1.0Ma, and the U-Pb isotopic values of 25 of the 30 zircon sites are located at or close to the same line of 238U, and the age of 238U is between 108.4 鹵0.9Ma~114.3 鹵1.0Ma for 23 of the 30 zircon sites. The weighted mean age is 111.7 鹵0.6 Ma MSWD1.4, which represents the age of formation of the bone cliff granite. Zircon rare earth elements have the characteristics of light rare earth deficiency, heavy rare earth enriched ce positive anomaly and negative EU anomaly, and the formation temperature is between 626 鈩，

本文編號(hào)：1932912