posted on 2019-07-22, 08:31authored byD Holwell, M Fiorentini, I McDonald, Y Lu, A Giuliani, D Smith, M Keith, M Locmelis
Ore deposits are loci on Earth where energy and mass flux are greatly enhanced and focussed, acting
as magnifying lenses into metal transport, fractionation and concentration mechanisms through the
lithosphere. Here we show that the metallogenic architecture of the lithosphere is illuminated by the
geochemical signatures of metasomatised mantle rocks and post-subduction magmatic-hydrothermal
mineral systems. Our data reveal that anomalously gold and tellurium rich magmatic sulfides in
mantle-derived magmas emplaced in the lower crust share a common metallogenic signature with
upper crustal porphyry-epithermal ore systems. We propose that a trans-lithospheric continuum exists
whereby post-subduction magmas transporting metal-rich sulfide cargoes play a fundamental role in
fluxing metals into the crust from metasomatised lithospheric mantle. Therefore, ore deposits are not
merely associated with isolated zones where serendipitous happenstance has produced mineralisation.
Rather, they are depositional points along the mantle-to-upper crust pathway of magmas and
hydrothermal fluids, synthesising the concentrated metallogenic budget available.
Funding
This work is funded by NERC SoS Consortium grant NE/M010848/1 and NE/M011615/1 “TeaSe:
tellurium and selenium cycling and supply”, and NERC grant NE/P017053/1 and NE/P017312/1
“FAMOS: from arc magmas to ores”; both awarded to the University of Leicester and Cardiff
University, respectively. The study was also funded by the Australian Research Council Centre of
Excellence for Core to Crust Fluid Systems (CE11E0070). YL acknowledges a Tibet pilot project
from CCFS and publishes with permission of the Executive Director of GSWA. This is contribution
1356 from the ARC Centre of Excellence for Core to Crust Fluid Systems (www.CCFS.mq.edu.au).