The Yerington Field Mapping course is an annual excursion exploring the alteration and mineralisation associated with skarn and porphyry deposits in the Yerington district, Nevada, USA. Yerington is a very unique example of porphyry copper and skarn mineralisation due to the considerable (60-90 degree) tilting that the entire region was subjected to during Cenozoic Basin and Range extension. The result of this extension is that the entire magmatic-hydrothermal system, from bottom to top, is laid out in near-horizontal surface exposures, allowing for a rare opportunity to enhance field mapping techniques in these types of mineralised environments.
from left to right: TMVC participants on the rocks; Course participants undertaking skarn mapping.
The course, organised by KLS Geological, is presented by John Dilles of Oregon State University, and Dick Tosdal of PicachoEx LLC. John Dilles, a key investigator of the district, has written multiple publications on the alteration mineral paragenesis and geochemistry associated with the Ann Mason porphyry copper deposit.
Last month, five TMVC personnel comprising four PhD students and the Hub's Director took part in the field trip, joining 24 other students and industry participants from over seven countries. Over the eight days of the course, they were exposed to the different alteration assemblages associated with porphyry and skarn deposits, from proximal to, to more distal from, the mineralisation zone. Participants completed three exercises in different settings, working at both regional and pit-bench scale, recording rock type, alteration, and mineralisation using the Anaconda mapping method. Although the weather was often quite cold and windy, the rock exposure was unbelievable, and well worth braving the elements. This course is highly recommended to anyone, student or otherwise, working in ore deposit systems.
TMVC participants discussing tourmaline-cemented breccia textures in hand specimens.
from top to bottom, left to right: Hub Director Professor David Cooke; PhD Candidates Ayesha Ahmed; Josh Phillips; Angela Escolme; Amos Garay; the group of TMVC participants
Story courtesy of PhD student Ayesha Ahmed
Images courtesy of David Cooke, and PhD students Angela Escolme and Josh Phillips