Publication Type:
Book ChapterSource:
Report of activities 2005, Manitoba. Geological Survey, Winnipeg, MB, Canada, Volume 2005, p.7-19 (2005)ISBN:
1498-0010Keywords:
basalts, Canada, Canadian Shield, Flin Flon Belt, Greenstone Belts, igneous rocks, intrusions, lithofacies, lithostratigraphy, Manitoba, massive deposits, massive sulfide deposits, metamorphic belts, Metamorphic rocks, metavolcanic rocks, North America, Paleoproterozoic, Precambrian, proterozoic, stratigraphic units, upper Precambrian, volcanic rocks, VOLCANISM, Western CanadaAbstract:
The Hidden formation defines the onset of a hangingwall mafic-volcanic episode to the host strata of the Flin Flon, Callinan and Triple 7 Cu-Zn sulphide orebodies. It comprises, from oldest to youngest, the 1920, Bomber, Newcor and Tower members. The 1920 member, which includes mafic flows with massive, pillowed and peperite facies, is overlain locally by felsic or undivided volcaniclastic rocks of variable composition. The Bomber member, which conformably overlies the 1920 member, occurs as massive, pillowed, breccia and peperite facies, and is itself conformably overlain by the Newcor member. The Newcor member includes massive-, pillowed- and breccia-facies flows, and is locally overlain by mafic volcaniclastic rocks. The Tower member, which conformably overlies the Newcor member, has yet to be examined in detail and is not discussed in this report. Rapid facies and thickness variations within the 1920, Bomber and Newcor members on the west limb of the F (sub 2) Hidden syncline are interpreted to have been formed in a synvolcanic graben. Of economic consideration with respect to this graben in the Hidden formation is that the faults controlling the location of the graben may have been active over a long period of time, including prior to Hidden formation volcanism, and therefore may have controlled hydrothermal conduits and formation of massive sulphide mineralization in underlying strata. Within the Hidden formation, the volcaniclastic units, which overlie the 1920 member and separate numerous flows within the Newcor member, likely represent hiatuses in volcanism and topographic depressions. They were likely formed in a vent-proximal environment with elevated hydrothermal activity and may therefore be prospective for Cu-Zn sulphide mineralization along strike at depth. The detailed stratigraphic subdivision and mapping of the Hidden formation strata on the west limb of the Hidden syncline have shown these rocks to have been structurally repeated by low-angle faults interpreted to be thrusts. This has considerable economic significance, as these thrust faults may also structurally repeat the stratigraphically underlying Flin Flon mine horizon.
Notes:
GeoRef, Copyright 2018, American Geological Institute.<br/>2006-033221<br/>1920 Member<br/>Bomber Member<br/>Hidden Formation<br/>Newcor Member
