CAJ | 학술논문

中条山绛县群变质火山岩是铜矿峪铜矿的赋矿岩石,其形成的年龄期次还没有很好的限定,构造背景还存在很大的争议。本文确定了变质石英斑岩的形成年龄为(2179±7) Ma,变质酸性火山岩的形成年龄为(2142±11) Ma,建议重新划分铜矿峪变质火山岩的层序,自下而上分别为变质石英斑岩(骆驼峰组)、变质基性火山岩(西井沟组)和变质酸性火山岩(竖井沟组)。其中铜矿峪铜矿主要赋存于骆驼峰组变质石英斑岩中。变质石英斑岩具有后碰撞花岗岩的特征,形成于由挤压向伸展转变的环境,其εNd(t)值为–2.21~–2.15,两阶段Nd模式年龄TDM2为2.75~2.79 Ga。变质酸性火山岩具有A2型花岗岩的特征,其εNd(t)值为–1.59~–0.94,两阶段Nd模式年龄TDM2为2.63~2.69 Ga,与变质石英斑岩一样都是由老地壳再造而来。变质基性火山岩富集 LREE、LIL及 HFS等元素,具有 Nb、Ta的负异常,无明显的 Ti负异常,部分样品具有 Zr、Hf 的正异常,具有受陆壳混染的大陆玄武岩特征,形成于伸展的构造背景。推测中条山—吕梁山在古元古代可能为华北克拉通古陆块的边缘,具有从造山到造山后伸展的复杂演化过程。铜矿峪斑岩型铜矿形成于陆块边缘由挤压转变到伸展的构造背景。
중조산강현군변질화산암시동광욕동광적부광암석,기형성적년령기차환몰유흔호적한정,구조배경환존재흔대적쟁의。본문학정료변질석영반암적형성년령위(2179±7) Ma,변질산성화산암적형성년령위(2142±11) Ma,건의중신화분동광욕변질화산암적층서,자하이상분별위변질석영반암(락타봉조)、변질기성화산암(서정구조)화변질산성화산암(수정구조)。기중동광욕동광주요부존우락타봉조변질석영반암중。변질석영반암구유후팽당화강암적특정,형성우유제압향신전전변적배경,기εNd(t)치위–2.21~–2.15,량계단Nd모식년령TDM2위2.75~2.79 Ga。변질산성화산암구유A2형화강암적특정,기εNd(t)치위–1.59~–0.94,량계단Nd모식년령TDM2위2.63~2.69 Ga,여변질석영반암일양도시유로지각재조이래。변질기성화산암부집 LREE、LIL급 HFS등원소,구유 Nb、Ta적부이상,무명현적 Ti부이상,부분양품구유 Zr、Hf 적정이상,구유수륙각혼염적대륙현무암특정,형성우신전적구조배경。추측중조산—려량산재고원고대가능위화북극랍통고륙괴적변연,구유종조산도조산후신전적복잡연화과정。동광욕반암형동광형성우륙괴변연유제압전변도신전적구조배경。
of the metamorphic quartz porphyry range from –2.21 to –2.15, and the corresponding two stage model ages TDM2 are mainly between 2.75 Ga and 2.79 Ga. The metamorphic acidic volcanic rocks are of A2type granite features, withεNd(t) values being –1.59 ~ –0.94, and two stage model ages being mainly between 2.63 Ga and 2.69 Ga. It is inferred that their magmatic origin was related to partial melting of older continental crust. The metamorphic mafic volcanic rocks are enriched in LREE, LIL and HFS elements, with Nb, Ta negative anomalies but no significant negative Ti anomalies. Some samples show Zr, Hf positive anomalies. These features are consistent with geochemical features of continental basalt, with assimilation of crust materials to various degrees in an extension tectonic setting. Zhongtiao–Lüliang Mountains might be located on the margin of the North China ancient continental block and underwent complicated geological evolution from orogeny to post-orogenic extension in the Paleoproterozoic period. The Tongkuangyu porphyry copper deposit was formed on the margin of the land mass in the conversional stage from compression to extension.