Besshi-type mineral systems in the Palaeoproterozoic Bryah Rift-Basin, Capricorn Orogen, Western Australia: Implications for tectonic setting and geodynamic evolution

Abstract

a b s t r a c tIn this contribution we use VMS mineral systems in the Bryah rift-basin to constrain the tectonic setting of the widespread mafic and ultramafic magmatism that characterises the rift-basin in question. Two distinct, but temporally closely associated, lithostratigraphic sequences, Narracoota and Karalundi Formations, are discussed. The Karalundi Formation is the main host of VMS mineral systems in the region. The Karalundi Formation consists of turbiditic and immature clastic sediments, which are locally intercalated with basaltic hyaloclastites, dolerites and banded jaspilites. We propose that the basaltic hyaloclastites, dolerites and clastics and jaspilites rocks, form a distinct unit of the Karalundi Formation, named Noonyereena Member. The VMS mineral systems occur near the north-east trending Jenkin Fault and comprise the giant and world-class DeGrussa and the Red Bore deposits. The nature of these deposits and their intimate association with terrigenous clastic rocks and dominantly marine mafic volcanic and subvolcanic rocks, as well as the common development of peperitic margins, are considered indicative of a Besshi-type environment, similar to that of present-day Gulf of California. Our Re-Os age data from a primary pyrite yielded a mean model age of 2012 AE 48 Ma, which coincides (within error) with recent published Re-Os data (Hawke et al., 2015) and confirms the timing of the proposed geodynamic evolution. We propose a geodynamic model that attempts to explain the presence of the Narracoota and Karalundi Formations as the result of mantle plume activity, which began with early uplift of continental crust with intraplate volcanism, followed by early stages of rifting with the deposition of the Karalundi Formation (and Noonyereena Member), which led to the formation of Besshi-type VMS deposits. With on-going mantle plume activity and early stages of continental separation, an oceanic plateau was formed and is now represented by mafic-ultramafic rocks of the Narracoota Formation.Ó 2015, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

3D Geological Model of the Touro Cu Deposit, A World-Class Mafic-Siliciclastic VMS Deposit in the NW of the Iberian Peninsula

“…Nevertheless, both in the cross-sections (Figure 7) and texturally ("rolled-balls"), in some of these areas, a brecciated feeder zone is detected, inclined at an angle to the rest of the sulfides and showing two preferential directions: N-S-trending (Vieiro) and E-W-trending (Fuente Rosas) (Figures 6-10). A similar situation is presented in [71] for the Palaeoproterozoic Bryah Rift-Basin in Western Australia.…”

The shallow marine VMS copper deposit of Yushui, Eastern Guangdong, South China: Evidence from geology, geochronology and geochemistry

“…The two volcanic layers at Yushui are ma c, which resemble ma c-siliciclastic-type VMS deposits in terms of their host-rock characteristics and Cu-rich nature (Barrie and Hannington 1999). Ma c-siliciclastic-type VMS deposits are generally associated with continental rifts (Pirajno 2009;Pirajno et al 2016), and the Yushui was likely formed in a rift basin (Fig. 1).…”

Lithogeochemical and Hyperspectral Halos to Ag-Zn-Au Mineralization at Nimbus in the Eastern Goldfields Superterrane, Western Australia

“…Such deposits occur in sedimented backarc or ocean rift environments, where the deep stratigraphy is likely to be dominated by mafic and ultramafic rocks. Examples of Besshi-type deposits include Windy Craggy of Canada, Besshi of Japan [1,77], and the DeGrussa deposit of Western Australia [78]. The Outokumpu-type Cu-Co-Zn-Ni-Ag-Au deposits of Finland are hosted by serpentinized ultramafic rocks (mantle peridotites), within a metasedimentary sequence [79].…”