Contents lists available at ScienceDirect Ore Geology Reviews journal homepage: www.elsevier.com/locate/oregeorev Entering an immature exploration search space: Assessment of the potential orogenic gold endowment of the Sandstone Greenstone Belt, Yilgarn Craton, by application of Zipf’s law and comparison with the adjacent Agnew Goldfield Rhys S. Davies a,b, ⁎ , David I. Groves c , Allan Trench a,d,e , John Sykes a,d,e,f , Jonathan G. Standing g a Centre for Exploration Targeting, School of Earth and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia b Alto Metals Ltd., 9/12-14 Thelma St, West Perth 6005, Australia c Orebusters Pty Ltd, Gwelup, WA 6018, Australia d Business School, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia e Minex Consulting (Perth Office), 10/7 Centro Avenue, Subiaco, WA 6008, Australia f Greenfields Research Ltd, Hunters Chase, Highfield Farm, Stripe Lane, Hartwith, Harrogate, North Yorkshire HG3 3HA, United Kingdom g Model Earth Pty. Ltd., 2/80 Colin St, West Perth 6005, Australia ARTICLE INFO Keywords: Archean orogenic gold Mineral Systems Concept Zipf’s law Sandstone Greenstone Belt Yilgarn Craton Western Australia ABSTRACT The Sandstone Greenstone Belt is an exploration-immature, regolith-covered, approximately 1000 sq. km belt, in the Southern Cross Domain of the Yilgarn Craton. In order to estimate potential endowment, historical gold production and deposit resource estimates are required to be quantitatively analysed for calculation of natural and residual gold endowment. The total residual gold endowment within the oxide zone of the Sandstone Greenstone Belt is estimated, by application of a Zipf’s law statistical assessment, to be 2.3 Moz. This miner- alisation is most likely contained in extensions of known deposits and several undiscovered deposits. The fresh rock of the Sandstone Greenstone Belt remains poorly explored. However, a conceptual endowment estimate can be made, based on a minerals system comparison between the exploration-immature Sandstone Greenstone Belt and the well-explored, geologically-similar Agnew Greenstone Belt, 100 km to the east. It is possible that natural endowment at Sandstone could total 21.3 Moz, with nine undiscovered deposits of > 0.5 Moz. Application of such a minerals-system integrated endowment assessment represents an effective motivator to embark on a well-resourced gold exploration campaign in the Sandstone Greenstone Belt, a currently immature exploration search space. 1. Introduction The Sandstone Greenstone Belt (SSGB) covers an area of approxi- mately 1000 sq. km in the Southern Cross Domain, Yilgarn Craton. Since the initial discovery of gold in the late 1800s, the belt has pro- duced over 1.2 Moz gold from surface, open pit and shallow under- ground workings, far less gold per unit area than most other Archean greenstone belts (Yun, 2000). Unlike neighbouring greenstone belts, there is limited research on gold mineralisation in the SSGB, so it is unclear whether significant residual primary mineralisation remains beneath workings in oxidised regolith profiles and in lesser explored parts of the belt. Whether future exploration presents an attractive cost- benefit opportunity requires an assessment of potential gold endow- ment. This paper considers the economic gold potential and represents a first attempt to systematically describe the geology and gold deposits of the SSGB. It incorporates empirical, conceptual and quantitative methods to assess its mineral endowment. Pre-existing and new critical datasets are compiled for the SSGB and interrogated using a mineral systems framework to define critical ele- ments of SSGB gold mineralising systems. The exploration database provides an overview of the maturity of the exploration search space and distribution of mineralisation. Field mapping and geophysical da- tasets are interpreted to outline geological domains and develop a greater understanding of the structure of the belt, thus defining pre- ferential conduits for the transport of auriferous fluids from gold source to site of deposition. Deposit structure and geology provide insights into deposit-scale features controlling deposition and style and timing of mineralisation. https://doi.org/10.1016/j.oregeorev.2018.01.020 Received 2 January 2017; Received in revised form 15 December 2017; Accepted 18 January 2018 ⁎ Corresponding author at: Centre for Exploration Targeting, School of Earth and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia. E-mail address: rhyssamuel.davies@research.uwa.edu.au (R.S. Davies). Ore Geology Reviews 94 (2018) 326–350 Available online 31 January 2018 0169-1368/ © 2018 Elsevier B.V. All rights reserved. T