aqueous geochemistry in mineral exploration · • stable isotopes • radiogenic isotopes •...
TRANSCRIPT
1
Aqueous Geochemistry in Mineral Exploration
Matthew I. Leybourne, GNS Science, Avalon, Lower Hutt, New Zealand
GNS Science
Outline
• Why aqueous geochemistry in mineral exploration?
• Field analyses - importance of pH and Eh
• Major species
• Trace metals and metalloids
• Stable isotopes
• Radiogenic isotopes
• Insights gained from water chemistry
• Seawater exploration for SMS
GNS Science
Utility of groundwater geochemistry
• Significant challenge for mineral exploration is to find new and deeper deposits, particularly in areas where either thick cover exists
• Where past exploration has already discovered shallow mineralization and exploration must extend to greater depth
• Groundwater recharges to depth, resulting in greater likelihood of interacting with buried mineralization compared to surficial geochemical methods, thus providing a three dimensional perspective
• Aqueous geochemistry can provide insights into other sample media and dispersion processes, secondary mineral formation
GNS Science
Natural waters vs AMD
GNS Science
Field based analyses
- pH and redox
KZK (Yukon) Spence (Chile)
GNS Science
Major species: Monturaqui, Salar de Punta Negra
and Hamburgo Basin
GNS Science
Major species: Kirkland Lake,
Ontario
GNS Science
Trace metals and metalloids
GNS Science
Trace elements - Spence, Chile
GNS Science
Trace elements - Spence, Chile
GNS Science
Trace elements - KZK, Yukon
GNS Science
Trace elements - Bathurst Camp, NB
GNS Science
Trace elements - Bathurst Camp, NB
GNS Science
Filtration versus non-filtration
GNS Science
Stable Isotopes - Spence, Chile
GNS Science
Stable isotopes
GNS Science
Stable isotopes - KZK, Yukon
Layton-Matthews and Leybourne (unpublished data)
GNS Science
Fingerprinting trace metal sources
de Caritat, P. and Kirste, D., (2005)
GNS Science
Radiogenic isotopes - Pb
• Pb has low solubility in waters
• Distinguishing true from false anomalies (organic, Mn or Fe oxide
accumulation of metals)
GNS Science
Radiogenic isotopes
GNS Science
Integration of geochemical modeling with real-
world examples
• Enhanced understanding of critical processes
• Application to metallurgical processes, remediation studies, supergene
mineralization
Formation of atacamite
GNS Science
Formation of soil anomalies
GNS Science
GNS Science
Aqueous
Geochemical
Exploration: The
Oceans
GNS Science
GNS Science
GNS Science
Plume Hunting
GNS Science
GNS Science
GNS Science
GNS Science
GNS Science
GNS Science
GNS Science
1.0
1.4
1.8
GNS Science
GNS Science
GNS Science
GNS Science
GNS Science
Sometimes the water comes to you…
26th International Applied Geochemistry Symposium Incorporating the New Zealand Geothermal Workshop
18-21 November, 2013, Rotorua, New Zealand
www.gns.cri.nz/iags