Tectonically-induced neptunian dykes and breccias of the Paleoproterozoic Teena Dolomite: Significance to stratiform zinc deposits in the McArthur Basin, Australia

IF 3.2 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Precambrian Research Pub Date : 2025-03-26 DOI:10.1016/j.precamres.2025.107768

Mana Ryuba , Malcolm W. Wallace , Ashleigh v.S. Hood , Christopher P. Reed , Nicola Cawood

{"title":"Tectonically-induced neptunian dykes and breccias of the Paleoproterozoic Teena Dolomite: Significance to stratiform zinc deposits in the McArthur Basin, Australia","authors":"Mana Ryuba , Malcolm W. Wallace , Ashleigh v.S. Hood , Christopher P. Reed , Nicola Cawood","doi":"10.1016/j.precamres.2025.107768","DOIUrl":null,"url":null,"abstract":"<div><div>A widespread system of breccias and neptunian dykes is present within the Paleoproterozoic Teena Dolomite of the McArthur Basin. Most breccia types within the unit are infilled by early fibrous marine cements and dark grey sediments. We interpret the dominant breccia types as <em>in-situ</em> synsedimentary fracture systems (neptunian dykes) while some matrix-supported breccias are likely to be mass flow deposits. Fibrous marine cements filling the neptunian dykes have several different textures and all now consist of dolomite. Petrographic evidence indicates the cements were likely precipitated as calcite and dolomitized during early diagenesis. The trace and rare earth element chemistry of the marine cements is typical of Paleoproterozoic marine cements and indicate relatively anoxic marine conditions.</div><div>The breccias in the Teena Dolomite appear to be the result of a basin-wide tectonic event that occurred during Teena Dolomite to early Barney Creek time at ∼1640 Ma. Early marine-cemented neptunian dykes likely formed by tectonic fracturing and gravitational collapse on tectonic highs. Many large stratiform Zn-Pb deposits in northern Australia (HYC, Teena, Lady Loretta, Mt Isa) are hosted by shales that are coeval with this tectonic event, suggesting a genetic link between tectonism and mineralization. We suggest that this ∼1640 Ma tectonic event is responsible for both the release of mineralization fluids (via faulting and/or dewatering), and the deposition of deeper water organic-rich fine-grained sediments that host the mineralization (via tectonic subsidence). This tectonic event appears to be an important component of the sedimentary exhalative mineral system in the Carpentaria Zinc Belt of northern Australia.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"422 ","pages":"Article 107768"},"PeriodicalIF":3.2000,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Precambrian Research","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0301926825000944","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

A widespread system of breccias and neptunian dykes is present within the Paleoproterozoic Teena Dolomite of the McArthur Basin. Most breccia types within the unit are infilled by early fibrous marine cements and dark grey sediments. We interpret the dominant breccia types as in-situ synsedimentary fracture systems (neptunian dykes) while some matrix-supported breccias are likely to be mass flow deposits. Fibrous marine cements filling the neptunian dykes have several different textures and all now consist of dolomite. Petrographic evidence indicates the cements were likely precipitated as calcite and dolomitized during early diagenesis. The trace and rare earth element chemistry of the marine cements is typical of Paleoproterozoic marine cements and indicate relatively anoxic marine conditions.

The breccias in the Teena Dolomite appear to be the result of a basin-wide tectonic event that occurred during Teena Dolomite to early Barney Creek time at ∼1640 Ma. Early marine-cemented neptunian dykes likely formed by tectonic fracturing and gravitational collapse on tectonic highs. Many large stratiform Zn-Pb deposits in northern Australia (HYC, Teena, Lady Loretta, Mt Isa) are hosted by shales that are coeval with this tectonic event, suggesting a genetic link between tectonism and mineralization. We suggest that this ∼1640 Ma tectonic event is responsible for both the release of mineralization fluids (via faulting and/or dewatering), and the deposition of deeper water organic-rich fine-grained sediments that host the mineralization (via tectonic subsidence). This tectonic event appears to be an important component of the sedimentary exhalative mineral system in the Carpentaria Zinc Belt of northern Australia.

查看原文本刊更多论文

古元古代蒂纳白云岩的构造诱导海王星岩脉和角砾岩：对澳大利亚麦克阿瑟盆地层状锌矿的意义

麦克阿瑟盆地古元古代蒂纳白云岩中存在广泛的角砾岩和海王星岩脉体系。单元内大部分角砾岩类型由早期纤维状海相胶结物和深灰色沉积物充填。我们认为主要角砾岩类型为原位同沉积断裂体系（海王星岩脉），而一些基质支撑角砾岩可能为质量流沉积。海相纤维胶结物充填海王星岩脉，有几种不同的结构，现在全部由白云岩组成。岩石学证据表明，胶结物可能在早期成岩作用中以方解石的形式析出并白云化。海相胶结物的微量元素和稀土元素化学特征具有典型的古元古代海相胶结物特征，显示了相对缺氧的海相环境。蒂纳白云岩中的角砾岩似乎是发生在蒂纳白云岩至早期巴尼溪时期（~ 1640 Ma）的一次全盆地构造事件的结果。早期海相胶结的海王星岩脉可能是由构造破裂和构造高点的重力崩塌形成的。澳大利亚北部许多大型层状铅锌矿床（HYC、Teena、Lady Loretta、Mt Isa）均由与该构造事件同时期的页岩所赋存，表明构造作用与成矿作用之间存在成因联系。我们认为，这一~ 1640 Ma的构造事件既导致了矿化流体的释放（通过断裂和/或脱水），也导致了承载矿化的富含有机物的深水细粒沉积物的沉积（通过构造沉降）。这一构造事件似乎是澳大利亚北部卡奔塔利亚锌带沉积喷发矿物体系的重要组成部分。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Precambrian Research 地学-地球科学综合

CiteScore

7.20

自引率

28.90%

发文量

325

审稿时长

12 months

期刊介绍： Precambrian Research publishes studies on all aspects of the early stages of the composition, structure and evolution of the Earth and its planetary neighbours. With a focus on process-oriented and comparative studies, it covers, but is not restricted to, subjects such as: (1) Chemical, biological, biochemical and cosmochemical evolution; the origin of life; the evolution of the oceans and atmosphere; the early fossil record; palaeobiology; (2) Geochronology and isotope and elemental geochemistry; (3) Precambrian mineral deposits; (4) Geophysical aspects of the early Earth and Precambrian terrains; (5) Nature, formation and evolution of the Precambrian lithosphere and mantle including magmatic, depositional, metamorphic and tectonic processes. In addition, the editors particularly welcome integrated process-oriented studies that involve a combination of the above fields and comparative studies that demonstrate the effect of Precambrian evolution on Phanerozoic earth system processes. Regional and localised studies of Precambrian phenomena are considered appropriate only when the detail and quality allow illustration of a wider process, or when significant gaps in basic knowledge of a particular area can be filled.