Geology and paleotectonic history of the Tally Pond Group, Dunnage Zone, Newfoundland Appalachians: an integrated geochemical, geochronological, metallogenic and isotopic study of a Cambrian island arc along the peri-Gondwanan margin of Iapetus

• Main Author: Pollock, Jeffrey Charles
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2004
• Subjects: Duck Pond; Newfoundland
• Online Access: https://research.library.mun.ca/6662/; https://research.library.mun.ca/6662/1/JeffreyCharlesPollock.pdf; https://research.library.mun.ca/6662/3/JeffreyCharlesPollock.pdf

The Cambro-Ordovician Victoria Lake Supergroup lies within the Exploits Subzone of the Newfoundland Appalachians and consists of felsic volcanic rocks with lesser amounts of mafic pillow lava, mafic and felsic pyroclastic rocks, chert, greywacke and shale. The group is a composite and structurally complex assemblage of volcanic, volcaniclastic, and epiclastic rocks which formed in a variety of island-arc, rifted arc, back-arc and mature-arc settings. It is divisible into several separate volcanic terranes that include the Tulks and Tally Pond belts. -- The Tally Pond Group comprises Cambrian island-arc felsic pyroclastic rocks with intercalated mafic volcanic rocks and epiclastic volcanic and sedimentary rocks. The group hosts numerous volcanogenic massive sulphide deposits including the Duck Pond and Boundary deposits, the largest undeveloped VMS deposits in the Victoria Lake Supergroup. In the area of the Duck Pond deposit these rocks form two structurally juxtaposed sequences, the Upper block and the Mineralized block which form a structural window through an overthrust package of Ordovician sedimentary rocks. -- 1:50 000 scale mapping and geochemical studies in the Tally Pond area have resulted in new interpretations of the local geology and a redefinition of the Tally Pond belt. The Tally Pond belt is now elevated to group status, composed of four distinct rock formations comprising Cambrian island arc felsic pyroclastic rocks with intercalated mafic volcanic rocks and epiclastic volcanic and sedimentary rocks. -- The oldest rocks in the study area are arc plutonic rocks of the Crippleback Lake Quartz Monzonite which forms the original basement to theTally Pond Group. The Lake Ambrose Formation is a sequence of dominantly mafic volcanic rocks comprised of vesicular and amygdaloidal, generally pillowed, flows and mafic to andesitic tuff, agglomerate and breccia that were unconformably deposited upon the Crippleback Lake Quartz Monzonite. The mafic volcanic rocks are intercalated with felsic volcanic rocks of ...