LIP-related ore deposits: new initiatives
Don Schissel, Global Exploration Search Leader
BHP Billiton
28 September 2004
There is a clear relationship between large igneous provinces (LIP’s) and the world’s nickel laterite and magmatic Nickel-Copper-Platinum Group Element ore deposits.
Figure 1 – Worldwide map of Large Igneous Provinces (LIPs) and their associated mafic/ultramafic rocks. Also shown are the major nickel camps (blue circles) and other nickel deposits (purple dots).Our mining company (BHP Billiton) is currently involved in a couple of initiatives that should be of value to both the scientific and mining communities. Furthermore, it is hoped that other mining companies may become similarly involved in funding initiatives related to LIPs-- to the benefit of the entire LIP community.
Atlas of Large Igneous Provinces (LIPs) Initiative
Modern exploration now uses computer-generated data sets to organize and review geologic and geophysical data. However, companies currently lack a robust dataset for LIPs through time. Discussion has begun with LIPs Commission co-leader Richard Ernst regarding BHP Billiton funding of a 3-4 year effort to produce an "Atlas of Large Igneous Provinces". What is envisioned is a
global digital atlas of LIPs over the time range 3.5 Ga to Present at a scale of 1:5,000,000, with an associated database of related information. Once produced this could be overlain as themes on a wide variety of global data sets.
In additional to financial support, BHP Billiton will also make available to the LIP Atlas team its global aeromagnetic data base which will aid in the interpretation of mafic rocks such as dike swarms, feeder sills, layered intrusions and mafic volcanics under shallow cover.
Age Dating Initiative
BHP Billiton has begun a program of funding U-Pb age dating of key LIP components (giant dyke swarm, sill provinces, layered intrusions, flood basalts). Obtaining ages for major mafic/ultramafic units is fundamental information that is of direct benefit both to the scientific community and mineral deposits community. Two aspects are important in this study: 1) LIPs are the main host for Ni-Cu-PGE deposits, and 2) precise dating is required to determine the full extent of LIPs throughout a craton, and in conjunction with paleomagnetism, represents the key tool for determining past continental reconstructions, and tracking LIPs (and metallotects) between cratons.
Currently, our focus is obtaining dates from mafic-ultramafic units in Canada and the southeast margin of Baltica (in the southern Ural Mountains of Russia), and Australia. We are currently funding dating by Dr. Mike Hamilton in the Jack Satterly Geochronology Laboratory at the University of Toronto (formerly of the Royal Ontario Museum), and Dr. Ulf Söderlund in the Lund University laboratory in Sweden.