SELECT IOCG VOLUME ABSTRACTS   BUY  
Back Next Next
Wernecke Mountains (Yukon) Breccias and Scattered Ore Occurrences: What Contribution to FeOx-Cu-Au-U Metallogeny ?
 
by
Peter Laznicka,   Data Metallogenica Centre, Australian Mineral Foundation, Adelaide, Australia.

in - Porter, T.M. (Ed), 2002 - Hydrothermal Iron Oxide Copper-Gold and Related Deposits: A Global Perspective, PGC Publishing, Adelaide, v. 2, pp 253-271.

ABSTRACT

   The Wernecke and Southern Ogilvie Mountains in Yukon are part of an almost east-west trending range in the northern Canadian Cordillera in which several areas of the Palaeo-Mesoproterozoic basement are exposed, enveloped by a Phanerozoic miogeoclinal sequence. The oldest division, the ~1.8 to 1.4 Ga Wernecke Supergroup, is interpreted as a 'clastic rift'. It is an up to 15 km thick pile, the bulk of which is a monotonous, well-bedded siltite-quartz rich litharenite-argillite, topped by carbonate-pelite units. Less than 1% of the area consists of small gabbro to diorite intrusions of several, mostly Palaeoproterozoic and Mesoproterozoic, generations. The predominantly brittle deformation regime produced extensive tracts of disrupted and dismembered units grading to tectonic (not subduction !) melange. These have been overprinted by large scale Na, Ca, Mg, Fe, CO2 and lesser Si, K metasomatism to produce widespread albitisation, chloritisation, carbonatisation, hematitisation and less extensive sericitisation (with local biotite) of the fractured sedimentary > > magmatic rocks as well as tectonic fragmentites. The 'Wernecke Breccia' is a metasomatised disaggregated breccia series and it is associated with hundreds of small scattered showings of specular hematite, magnetite and chalcopyrite, several occurrences of U and Co minerals, and anomalous gold. Not even a marginally economic orebody has so far been discovered despite intermittent exploration going back to the 1960s. It appears that we are dealing with a moderately deep (closely above the ductile-brittle interface) level of regional release and displacement of metals from source rocks (Fe, Cu and Co from gabbros; U perhaps from carbonaceous argillites) by metasomatic destruction of the carrier minerals. However, the system lacked sufficient plumbing and the channelling required to produce better metal accumulations at higher levels.

Buy Top   |   PGC Publishing     |   PorterGeo Home


This book is NOW AVAILABLE FOR ORDER via the web by selecting the BUY button above.

This abstract was printed from the PGC Publishing website https://portergeo.com.au/publishing.


PGC Logo
Porter GeoConsultancy Pty Ltd
 Ore deposit database
 Conferences & publications
 International Study Tours
     Tour photo albums
 Experience
PGC Publishing
 Our books  &  bookshop
     Iron oxide copper-gold series
     Super-porphyry series
     Porphyry & Hydrothermal Cu-Au
 Ore deposit literature
 
 Contact  
 What's new
 Site map
 FacebookLinkedin