Abstract

Analysts of texture, mineralogy, and chemistry of bottom sediments in Conception Bay, southeastern Newfoundland has shown: (1) Sediment texture is related to water depth, (2) water depth, CaCO3 content, organic-C content, and feldspar/quartz peak area ratios are all related to sediment mean grain size, (3) concentrations of major elements are related to clay, organic-C, and CaCO3 contents and feldspar/quartz peak area ratios of sediments, (4) concentrations of trace elements are related to clay and organic-C contents, (5) sediment pH is related to Organic-C and CaCO3 contents, and (6) sediment temperature is related to water depth. These relationships indicate that four interrelated factors regulate sedimentary geochemical variables: Source and depositional environment are primary factors that regulate the type of solid components comprising sediments and sediment grain size, respectively; grain size is a secondary factor that regulates mineral and organic matter content of sediments; solids composition (quartz, feldspar, clay minerals, CaCO3, and organic matter) is a tertiary factor that regulates sediment chemistry. Sediment pH is regulated mainly by CaCO3 content and temperature is regulated by depositional environment. Particular attention should be paid to these factors when conducting sedimentary geochemical investigations.A surface layer of brick-red, iron-enriched sediment around Bell Island, which is the waste product of former mining activities, provides the only evidence of man's alteration of the Conception Bay bottom environment. Therefore, trace and major element concentrations in bottom sediments described in this paper are natural background levels which can be utilized for a future comparative study in the event of increased urbanization and/or industrialization of the Conception Bay area.Results of echosounder profiling have shown that the physiography of Conception Bay has been glacially modified. Four sets of marine terraces have been identified at water depths of 110–120, 90, 70–75, and 20 m. These terraces are correlative with others found elsewhere in Atlantic Canada.

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