Geology and mineral occurrences in the Faribault Brook area, Cape Breton Island, Nova Scotia
LA3 .A278 2011
Barr, Sandra M.
Master of Science
Earth & Environmental Sciences
The Jumping Brook Metamorphic Suite (JBMS) is located in the western part of the Aspy terrane near Cheticamp, Cape Breton Island. In the Faribault Brook area, the JBMS hosts numerous volcanogenic massive sulphide-type occurrences and hence has been an exploration target for more than 100 years. Geological mapping and core logging carried out in the summer of 2007 focused on the JBMS in the Faribault Brook area, where the unit consists of the (1) Faribault Brook metavolcanic (FBMV) unit, composed mainly of metabasalt, with minor felsic volcanic and metasedimentary/ metatuffaceous rocks, (2) Barren Brook schist (BBS), mostly medium- to coarse-grained metasedimentary rocks with minor amounts of felsic metavolcanic rocks, and the Dauphinee Brook schist (DBS), fine- to medium-grained metasedimentary rocks. Based on a locally demonstrable intrusive relationship with the ca. 550 Ma Cheticamp Pluton and related diorite, as well as previously reported U-Pb ages of ca. 551 and 546 Ma for detrital zircon in the BBS and DBS, the JBMS is considered to be Late Neoproterozoic in age. Known mineral occurrences are mostly associated with silicified metarhyolite and mafic metavolcanic rocks of the FBMV unit, and with Silurian rhyolite porphyry. The metabasalt of the FBMV unit locally preserves pillow structures and is characterized by depletion in light rare-earth elements indicative of N-MORB affinity. The chemical characteristics combined with the quartz-rich and turbiditic characteristics of associated sedimentary rocks suggest deposition in a back-arc basin setting. The age of the Jumping Brook Metamorphic suite suggests that no directly correlative units are known in the Aspy terrane or Bras d’Or terranes, but such rocks may occur elsewhere in Ganderia in the New River terrane in southern New Brunswick and in central Newfoundland.
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