BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:How crustal exhumation rates determine the fate of porphyry copper
  deposits - Frances Cooper\, University College London
DTSTART:20250603T110000Z
DTEND:20250603T120000Z
UID:TALK225217@talks.cam.ac.uk
CONTACT:Dr Rachael Rhodes
DESCRIPTION:Copper is an essential component in most clean energy technolo
 gies and fundamental to the success of the global green energy transition.
  It is mainly sourced from porphyry copper deposits (PCDs)\, which are met
 al-rich magmatic-hydrothermal systems typically associated with subduction
  zones. However\, PCDs are rare and proving increasingly difficult to find
 . They are also high tonnage (~100–1\,000 Mt) and low concentration (ave
 rage production grade is ~0.53% Cu)\, so enormous volumes of rock must be 
 extracted to retrieve tiny amounts of metal. As the global demand for copp
 er surges to meet ambitious green energy targets\, society is confronted w
 ith the dual challenge of locating increasingly elusive PCDs while priorit
 ising those with the lowest potential environmental impact. This means fin
 ding the most copper-rich (highest-grade) deposits\, which require the sma
 llest amount of extraction and processing\, and thus create the least dama
 ge to the environment.\n \nThe exhumation history of a PCD plays an import
 ant role in determining its copper grade. During the initial “hypogene
 ” stage of mineralisation\, rapid exhumation is required to advect heat 
 towards the surface\, allowing metal-carrying magmas and fluids to transpo
 rt their cargo into the shallow crust. To maximise ore grades\, exhumation
  must then slow considerably so the deposit can linger close to the surfac
 e where secondary “supergene” enrichment by oxygenated groundwater wat
 er takes place. In this talk\, I will present an example from the Eocene-O
 ligocene copper belt in northern Chile\, which is the world’s premier PC
 D province\, but disappears to the north as it approaches the Peruvian bor
 der. By combining U-Pb zircon geochronology\, Al-in-hornblende geobarometr
 y\, low-temperature (U-Th-Sm)/He thermochronology\, and thermal-kinematic 
 modelling to track exhumation histories\, I will show that (1) both the ra
 te and timing of exhumation are critical in determining the potential of a
 n area to host high-grade PCDs\; and (2) northward disappearance of the co
 pper belt close to Peru is due to higher exhumation rates in that area\, w
 hich prevented supergene enrichment and potentially led to loss of deposit
 s via surface erosion.
LOCATION:Department of Earth Sciences\, Tilley Lecture Theatre
END:VEVENT
END:VCALENDAR