Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

The geochemistry of the Lower Proterozoic Willyama Complex Volcanics, Broken Hill Block, New South Wales

James, S. D., Pearce, Julian A. and Oliver, R. A. 1987. The geochemistry of the Lower Proterozoic Willyama Complex Volcanics, Broken Hill Block, New South Wales. Geological Society, London, Special Publications 33 (1) , pp. 395-408. 10.1144/gsl.sp.1987.033.01.27

Full text not available from this repository.

Abstract

The major and trace element geochemistry of the early to middle Proterozoic meta-igneous rocks of the Willyama Complex in the Broken Hill Block indicates that the basic rocks originated by partial melting of a depleted mantle source, followed by fractional crystallization along a trend of strong iron enrichment coupled with some crustal assimilation. At least some of the intermediate-acid rocks were derived from fractionation of these basic parents, but major crustal involvement may be necessary to explain the large quantities of felsic volcanics in the lower part of the Complex. The volcanic rocks in the Broken Hill mine area show an unusually high degree of primary iron enrichment (up to 25 wt % total iron as Fe2O3) and a lesser degree of bimodality than elsewhere. By analogy with Recent ferrobasalt provinces, this extreme iron enrichment may indicate an origin in a propagating rift where small, high-level magma chambers separated from the magma source. If so, the consequent high geothermal gradient and high fracture permeability may have provided the necessary conditions for genesis of the Broken Hill ore deposit.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Earth and Environmental Sciences
Subjects: Q Science > QE Geology
ISSN: 0305-8719
Last Modified: 04 Jun 2017 02:04
URI: https://orca.cardiff.ac.uk/id/eprint/8508

Citation Data

Cited 37 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item