当前位置: X-MOL 学术Miner. Deposita › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
The tectonic setting and evolution of the 2.7 Ga Kalgoorlie–Kurnalpi Rift, a world-class Archean gold province
Mineralium Deposita ( IF 4.4 ) Pub Date : 2018-01-11 , DOI: 10.1007/s00126-017-0778-9
Walter K. Witt , Kevin F. Cassidy , Yong-Jun Lu , Steffen G. Hagemann

The Yilgarn Craton results from three major mantle input events (at ca 3.0–2.9, 2.8 and 2.7 Ga) that have interacted with > 3.0 Ga continental crust. Zircon geochronology and Sm-Nd isotopic data subdivide the craton into an older Yilgarn proto-craton and the younger, more primitive Eastern Goldfields Superterrane (EGST). Formation of the Kalgoorlie-Kurnalpi Rift (KKR) within the EGST was associated with the 2.7 Ga event, which exploited weakened crust at the eastern margin of the Yilgarn proto-craton where thick sequences of komatiite and basalt were erupted between ca 2710 and 2690 Ma in the Kalgoorlie Terrane. Calc-alkaline volcanism in the Kurnalpi Terrane began at ca 2730 Ma and continued to ca 2690 Ma, overlapping rifting and plume-related volcanism in the Kalgoorlie Terrane. Deposition of siliciclastic sedimentary rocks within basins at ca 2660 resulted from an intra-orogenic extensional event and coincided with the transition from High-Ca to Low-Ca granite magmatism and peak emplacement of intrusions with a metasomatised mantle source component. Most aspects of the KKR are satisfied by broadly coincident plume-related magmatism in the Kalgoorlie Terrane and westward subduction to the east of the Burtville Terrane. Geochemical characteristics of 2730–2700 Ma calc-alkaline volcanism and 2685–2630 Ma low-SiO 2 and alkali-rich intrusions support models for a continental margin subduction zone setting. World-class gold deposits formed in reactivated margins of the KKR, which became flux zones for mantle-derived magmas, hydrothermal fluids and heat during 2675–2620 Ma orogenesis. The orogenic gold mineralisation can be subdivided into proximal intrusion-related and distal-source deposits.

中文翻译:

世界级太古代金矿区 2.7 Ga 卡尔古利-库纳尔皮裂谷的构造背景和演化

Yilgarn Craton 由三个主要的地幔输入事件(大约 3.0-2.9、2.8 和 2.7 Ga)产生,它们与 > 3.0 Ga 大陆地壳相互作用。锆石年代学和 Sm-Nd 同位素数据将克拉通细分为更古老的 Yilgarn 原始克拉通和更年轻、更原始的东部金矿超级地体 (EGST)。EGST 内 Kalgoorlie-Kurnalpi 裂谷 (KKR) 的形成与 2.7 Ga 事件有关,该事件利用了约 2710 至 2690 Ma 之间的 Yilgarn 原克拉通东缘的弱化地壳,在那里喷发了厚层的科马提岩和玄武岩在卡尔古利地层。Kurnalpi Terrane 的钙碱性火山活动开始于大约 2730 Ma 并持续到大约 2690 Ma,与 Kalgoorlie Terrane 中的裂谷和羽流相关的火山活动重叠。大约 2660 年盆地内硅质碎屑沉积岩的沉积是造山带内伸展事件的结果,与从高钙到低钙花岗岩岩浆作用的转变以及具有交代地幔源成分的侵入体的峰值就位相吻合。KKR 的大多数方面都满足于卡尔古利地体中与羽流相关的岩浆作用和 Burtville 地体以东的向西俯冲。2730-2700 Ma钙碱性火山作用和2685-2630 Ma低SiO 2 和富碱侵入体地球化学特征支持大陆边缘俯冲带背景模型。世界级的金矿床形成于 KKR 的再活化边缘,在 2675-2620 Ma 造山作用期间成为地幔源岩浆、热液流体和热量的通量带。
更新日期:2018-01-11
down
wechat
bug