CAJ | 학술논문

内蒙古东乌旗宾巴勒查干分布有大面积的侵入岩，本文选取其中的粗中粒正长花岗岩进行了同位素年代学及岩石地球化学研究，采用锆石SHRIMPU-Pb法得到加权平均年龄为220．4±2．5Ma（MSWD=0．83），所测锆石震荡环带发育，具有岩浆锆石特征，表明该年龄为花岗岩成岩年龄。岩体属富钾的过铝质岩石，稀土配分曲线以Eu负异常明显、轻稀土相对富集、重稀土具微弱的负斜率为特征。微量元素显示岩体的Ba具明显的负异常，Rb、Th相对富集，其它不相容元素相对亏损，Y、Yb均低于洋脊花岗岩标准化值。笔者认为岩体形成于西伯利亚板块和中朝板块拼合之后的后造山伸展背景下。
내몽고동오기빈파륵사간분포유대면적적침입암，본문선취기중적조중립정장화강암진행료동위소년대학급암석지구화학연구，채용고석SHRIMPU-Pb법득도가권평균년령위220．4±2．5Ma（MSWD=0．83），소측고석진탕배대발육，구유암장고석특정，표명해년령위화강암성암년령。암체속부갑적과려질암석，희토배분곡선이Eu부이상명현、경희토상대부집、중희토구미약적부사솔위특정。미량원소현시암체적Ba구명현적부이상，Rb、Th상대부집，기타불상용원소상대우손，Y、Yb균저우양척화강암표준화치。필자인위암체형성우서백리아판괴화중조판괴병합지후적후조산신전배경하。
Intrusive rocks are widespread in the Binbalechagan, Dongwuqi, Inner Mongolia Autonomous Region. This paper selectes coarse-medium grained syenogranites (CMGS) in the region for isotope chronological and geochemical studies. By zircon SHRIMP U-Pb dating, weighted mean age of 220.4 ± 2.5 Ma(MSWD = 0.83) is obtained. The zircon oscillatory rings are well developed with typical pattern of magmatic zircon, so the result may represent the diagenetic age of the granite. CMGS is characterized by K enrichment, peraluminous, LREE relatively enriched, substantial negative Eu anomalies, HREE with weak negative gradient, Ba with obvious nega- tive anomalies, Rb and Th relatively enriched, other incompatible elements relatively depleted, both Y and Yb lower than the normalized values of ocean ridge granite. CMGS probably formed under post-orogenic extension setting after the convergence between the Siberian plate and Sino-Korean plaeo-plate.