Mesoproterozoic plume‐modified orogenesis in eastern Precambrian Australia

Abstract

Tectonic models for the latest Paleoproterozoic to earliest Mesoproterozoic evolution of eastern Australia (circa 1620–1500 Ma) are diverse and either emphasize plume or plate margin activity, neither of which satisfactorily explains all geological observations. The dichotomy is largely attributed to geochemical, spatial and temporal data that suggest voluminous A‐type felsic magmas are plume related, whereas distribution of arc‐related magmas and intense orogenic overprint suggest plate margin activity. The salient geological events include arc‐related magmatism at circa 1620–1610 Ma followed by a magmatic hiatus coincident with north‐south crustal shortening (1610–1590 Ma) and a magmatic flare‐up of A‐type felsic magmas throughout the Gawler Craton (circa 1595–1575 Ma). These magmas form the oldest component of a northward younging hot spot track that extends to the Mount Isa Inlier. At circa 1590–1550 Ma, arc magmatism resumed along the northern margin of the Gawler Craton and the rest of eastern Australia records a 90° shift in the regional shortening direction related to activity along the eastern margin of the Australian continent. A plume‐modified orogenic setting satisfies all of the spatial and temporal relationships between magma generation and orogenic activity. In this model, the Gawler Craton and the adjacent subduction zone migrated over a mantle plume (circa 1620–1610 Ma). Resultant flat subduction caused transient orogenesis (1610–1595 Ma) in the overriding plate. Slab delamination and thermal assimilation of the plume and the subducting slab caused a switch to crustal extension in the overriding plate, resulting in extensive mantle‐derived and crustal melting in the Gawler Craton (1595–1575 Ma).

Glacial dispersion of hydrothermal monazite in the Prominent Hill deposit: An exploration tool

“…1.60-1.58 Ga (e.g. Betts et al, 2009;Forbes et al, 2008;Giles et al, 2002Giles et al, , 2004. Mineralisation in the Prominent Hill area also developed during this event (Belperio et al, 2007).…”

“…1.60-1.58 Ga (e.g. Belperio et al, 2007;Betts et al, 2009;Davidson et al, 2007;Forbes et al, 2008;Giles et al, 2002Giles et al, , 2004Reid et al, 2011;Skirrow et al, 2007), and are hosted within Palaeoproterozoic (e.g. ca.…”

The noble gas systematics of late-orogenic H2O–CO2 fluids, Mt Isa, Australia

“…The hydrothermal fluids are estimated to have had d 18 O of +8& to +13&, variable d 13 C (À7& to +2 &) and fractionated dD (À50& to À130&) values that are consistent with the involvement of Oliver (1995), MacCready et al (1998 and Betts et al (2009), with age data from Page andSun (1998), Oliver et al (2004) and Mark et al (2006b). Stars indicate the locations of previous Br/Cl-I/Cl and 40 Ar/ 36 Ar studies of regional Na-Ca alteration; the Ernest Henry, Eloise, Osborne and Starra iron-oxide-copper-gold deposits; and the Mt Isa Copper deposit (Kendrick et al, 2006a(Kendrick et al, ,b,c, 2007(Kendrick et al, , 2008aFisher and Kendrick, 2008).…”

An Early Permian (ca. 280Ma) silicic igneous province in the Alxa Block, NW China: A magmatic flare-up triggered by a mantle-plume?

“…These SLIPs are characterized by large volumes (N10 5 km 3 ), of predominantly rhyodacite-rhyolite compositions, long periods of magmatic evolution (b40 myr) and were located along paleo-or active continental margins (Bryan, 2007;Bryan et al, 2002). Unlike the mafic LIPs commonly related to mantle plumes (e.g., Bryan and Ernst, 2008;Chung et al, 1998;Coffin and Eldholm, 1994;Buchan, 2001, 2003), the mechanisms for the formation of the SLIPs are not as clear and the generation of SLIPs may be related to continental rifting, mantle plumes or back arc extension (Betts et al, 2009;Bryan, 2007;Bryan and Ferrari, 2013;Bryan et al, 2002;Pankhurst et al, 2000Pankhurst et al, , 2011b.…”