New Zealand Journal of Marine and Freshwater Research abstracts

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Lithium and rubidium in the Waikato River, New Zealand

JANE E. BOWER'S MICHAEL H. TIMPERLEY2*

'Spectrum Resources Ltd P.O. Box 17036, Greenlane Auckland, New Zealand
2Taupo Research Laboratory Department of Scientific and Industrial Research Box 415, Taupo, New Zealand

Abstract Lithium and rubidium in the Waikato River originate partly from geothermal fluids and partly from weathering of surficial volcanic rocks. This paper reports on the distribution and behaviour of these metals in the river system. Total Li concentrations in the river water increased from 0.079 g/m³ at the Lake Taupo outlet to 0.435 g/m³ at Mercer, but the ratios of filtrable to particulate metal decreased from 1.82 to 0.322, respectively. The corresponding concentrations for Rb were 0.038 and 0.626 g/m³, and the ratios were 0.095 and 0.040. Geothermal fluids are the source of about 80% of filtrable Li but only 50% of filtrable Rb. Weathering of volcanic rocks contributes the remainder of the metals. Approximately 11001 each of total Li and total Rb flow annually past Lake Aratiatia and more than 99% of these totals flow into the Tasman Sea. About 31 of Li and 61 of Rb accumulate each year into reservoir sediment; reservoir macrophytes, which probably turn over each year, could contain up to 0.5 t of Li and 8.41 of Rb. Within the reservoir sediments and macrophytes, Li, Rb, and K each show different distributions.

Keywords lithium; rubidium; Waikato River; geothermal input; weathering; macrophytes

New Zealand Journal of Marine and Freshwater Research, 1988, Vol. 22: 201-214 ; Crown copyright 1988Received 29 April 1986; accepted 29 June 1987

PDF file of entire paper: medium quality (939K); (scanned from paper original: notes about this process)

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