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Geochemical exploration for tin using suspended sediment sample media
Journal of Geochemical Exploration, 29 (1987) 409-410
409
Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
Geochemical Exploration for Tin Using Suspended Sediment Sample Media D.R. GLADWELL and R.E. L E T T
Barringer Magenta Ltd., 304 Carlingview Drive, Rexdale Ont. M9W 5G2, Canada (Received June 16, 1986}
Previous investigations have shown that there is widespread depletion of Sn in the fine fraction of stream sediments. This depletion may reflect the ubiquitous unavailability of fine-grained cassiterite for incorporation into the sediment or, more likely, preferential partitioning of fine-grained cassiterite into the suspended washload of drainage systems. Despite the importance of suspended load relative to the total material transported by streams, analysis of suspended sediments for metals (including Sn) has not been widely used in geochemical exploration. Results of orientation studies in Canada and England to investigate the feasibility of suspended sediment analysis for cassiterite in geochemical exploration for Sn deposits are described in this paper. Study areas in Cornwall, England; southern Novia Scotia and central British Columbia were selected in order to compare Sn dispersion in the suspended stream sediment load under contrasting secondary environments. In each area, suspended sediment was recovered from stream water by filtering a volume of the water and the filtrate analyzed for cassiterite Sn by an ammonium iodide attack-volatile hydride atomic absorption spectrophotometric technique. Conventional stream sediments were also collected to compare the partitioning of Sn between the two sample media. In southwest Cornwall, analysis of conventional sediments from streams draining mineralized areas indicated dispersion trains were normally very short, whereas anomalous cassiterite Sn levels (greater than 12.6 ppb per litre Sn) in suspended sediments could be detected up to 10 km from known Sn deposits. Suspended sediments recovered from a stream draining the east Kemptville deposit in Nova Scotia contained 32.6 ppt per litre cassiterite Sn compared to levels in background streams of less than 10 ppt per litre. Anomalous Sn values were also detected in the suspended sediment from several streams in an area roughly 15 km east of the deposit where no Sn occurrences are known although high bedrock Sn levels were found in the area by this study. Anomalous cassiterite Sn values were also detected in streams draining basemetal occurrences reported to contain stannite in the Sandon area of British Columbia. These data clearly show that Sn anomaly contrast and persistance
0375-6742/87/$03.50
© 1987 Elsevier Science Publishers B.V.
410 is increased using a suspended sediment sample medium. The application of this method to exploration for W and precious metal deposits will also be discussed.
409
Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
Geochemical Exploration for Tin Using Suspended Sediment Sample Media D.R. GLADWELL and R.E. L E T T
Barringer Magenta Ltd., 304 Carlingview Drive, Rexdale Ont. M9W 5G2, Canada (Received June 16, 1986}
Previous investigations have shown that there is widespread depletion of Sn in the fine fraction of stream sediments. This depletion may reflect the ubiquitous unavailability of fine-grained cassiterite for incorporation into the sediment or, more likely, preferential partitioning of fine-grained cassiterite into the suspended washload of drainage systems. Despite the importance of suspended load relative to the total material transported by streams, analysis of suspended sediments for metals (including Sn) has not been widely used in geochemical exploration. Results of orientation studies in Canada and England to investigate the feasibility of suspended sediment analysis for cassiterite in geochemical exploration for Sn deposits are described in this paper. Study areas in Cornwall, England; southern Novia Scotia and central British Columbia were selected in order to compare Sn dispersion in the suspended stream sediment load under contrasting secondary environments. In each area, suspended sediment was recovered from stream water by filtering a volume of the water and the filtrate analyzed for cassiterite Sn by an ammonium iodide attack-volatile hydride atomic absorption spectrophotometric technique. Conventional stream sediments were also collected to compare the partitioning of Sn between the two sample media. In southwest Cornwall, analysis of conventional sediments from streams draining mineralized areas indicated dispersion trains were normally very short, whereas anomalous cassiterite Sn levels (greater than 12.6 ppb per litre Sn) in suspended sediments could be detected up to 10 km from known Sn deposits. Suspended sediments recovered from a stream draining the east Kemptville deposit in Nova Scotia contained 32.6 ppt per litre cassiterite Sn compared to levels in background streams of less than 10 ppt per litre. Anomalous Sn values were also detected in the suspended sediment from several streams in an area roughly 15 km east of the deposit where no Sn occurrences are known although high bedrock Sn levels were found in the area by this study. Anomalous cassiterite Sn values were also detected in streams draining basemetal occurrences reported to contain stannite in the Sandon area of British Columbia. These data clearly show that Sn anomaly contrast and persistance
0375-6742/87/$03.50
© 1987 Elsevier Science Publishers B.V.
410 is increased using a suspended sediment sample medium. The application of this method to exploration for W and precious metal deposits will also be discussed.