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

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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.

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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.