250 year record of environmental cyclicity in the Ohau catchment : a sedimentary and palaeomagnetic study

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Fitzgerald, Shannon.

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Abstract:

Environmental magnetic methods were used to determine the environmental history recorded in sediment cores (L - 1407 and L - 1408) collected from the bed of Lake Ohau, South Island, New Zealand. Fluctuating magnetic intensity in both cores exhibits 1 00 year periodicity interpreted to originate from palaeoclimatic cycles. Small magnetic intensity fluctuations possibly reflect El/Nino and La Nina cycles. Stratigraphy in both cores mainly comprises ,...ef'varves which provide a means for dating changes in environmental processes. Turbidites at 81 0 mm and 1810 mm in sediment core L - 1407 closely correlate with palaeoseismic events during September 1888 in North Canterbury and rupture of the Alpine Fault during 1717, respectively. Inclination and declination obtained from the processed data exhibits secular variation. From the constructed age models sediment cores L- 1407 and L - 1408 have a mean sedimentation rate of~ 8 mm/yr and~ 7 mm/yr, respectively.

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vii, 62 leaves : col. ill., col. maps (some folded) ; 30 cm. + 1 CD-ROM (4 3/4 in.)

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2004Fitzgerald

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http://download.otagogeology.org.nz/temp/Abstracts/2004Fitzgerald.pdf

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Citation

Fitzgerald, Shannon., “250 year record of environmental cyclicity in the Ohau catchment : a sedimentary and palaeomagnetic study,” Otago Geology Theses, accessed February 13, 2025, https://theses.otagogeology.org.nz/items/show/428.

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