Overburden Geochemistry and Possible Relations To Gold-Bearing Alluvial Deposits, Southwest Gaspésie, Quebec

Abstract

Possible sources of various elements and minerals, including gold and: garnet, :found in anomalous concentrations in stream sediments within the Matapedia River drainage basin in south west Gaspesie were investigated in a study of the geomorphology and compositional nature or the upland overburden in an area or about 2400 km2. Investigations on the, geomorphology of the area show that Pleistocene events have had little influence in shaping the observed topography and drainage patterns. The project area is a dissected plateau with summit altitudes from 1300 to 1500 feet (396 to 457 m) above sea level, and floors or the major valleys 'from 150 to 750 feet (46 to 229 m) above sea level. Upland overburden is thin and commonly not thicker than the soil profile. It varies from a diamict with a large proportion of the underlying bedrock and a lesser component or far-travelled material, to a rubble composed almost entirely of weathered underlying bedrock. Major element analyses of the -60 mesh (<250 um) fraction of overburden and trace element analyses of heavy mineral concentrates show changin compositions across the area in approximate correspondence with changes in underlying rock types. The abundance of heavy minerals in overburden is related to the concentration of Shield-derived minerals within the heavy mineral 'fraction. The distribution of heavy mineral abundances in turn rerlects the distribution of bedrock lithologies and suggests that lithological differences may have affected the pattern ofdeposition and erosion of the Laurentide ice sheet as it flowed across the area. Gold analyses within the -60 mesh (<250 um) fraction of overburden show that gold is in very low concentrations. However, gold analyses within heavy mineral concentrates extracted from overburden provide a better estimate of gold variation across the area and outline a number of anomalous zones. High abundances of gold in heavy mineral concentrates from overburden samples collected north of the mouth of the Assemetquagan River and east of the Matapeda River (within a 36 km2 area) support the hypothesis of a local source to the north-northwest for the alluvial gold at the mouth of the Assemetquagan River.

Can S/CRS Solve the United States Government's Interagency Coordination Challenges?

“…43 Disinclined to provoke Beijing, but comfortable with Taiwan's de-facto independence and democratic government, the vast majority of Taiwanese are not interested in "unification" under the terms offered by the PRC. 44 Granted, when democracy arrived on the island, ethnic tension and bitter internal political struggles soon followed. 45 Nevertheless, there is a broad consensus on the critical issue − The Taiwanese are willing to fight if attacked.…”

An Interpretation of Late Quaternary Glacial Flow Indicators in the Baie des Chaleurs Region, Northern New Brunswick

“…In contrast, David and Bédard (1986) have shown southeastern transport of unique granitic erratics by ice from the central Notre-Dame Mountains to the Baie des Chaleurs; this unique distribution of erratics could have been accomplished by local ice. Farther to the northwest, Canadian Shield erratics seem to be restricted to low elevation "gaps" in the Notre-Dame mountain range (LacTémiscouata-Edmundston and Matapédia Lake-River Lows) according to data from David and Lebuis (1985), Maurice (1986), and Bernier et al (1987). The distribution of erratics in northern Maine (Newman er a/., 1985) and northern New Brunswick (Rappol, 1986b) shows less than 0.5 % Shield-derived clasts.…”

“…Some Shield indicators (Genes era/., 1981 ;Maurice, 1986;David and Lebuis, 1985) were transported across the Notre-Dame Mountains in a southeastward direction, but did not reach north-central New Brunswick (see also Bernier et al, 1987). An interaction of Laurentide and Appalachian ice masses (Model I of Genes et ai, 1981) whereby Laurentide ice fuses with, as opposed to overrides, Appalachian ice, together with the drainage of dirty basal ice through the Laurentian Channel (Gauthier, 1978b) can satisfactorily explain this discrepancy (see below).…”