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dc.contributor.authorNelson, Campbell S.
dc.date.accessioned2010-11-11T02:56:13Z
dc.date.available2010-11-11T02:56:13Z
dc.date.issued1983
dc.identifier.citationNelson, C.S. (1983). Bottom sediments of Lake Rotoma. New Zealand Journal of Marine and Freshwater Research, 17, 185-204.en_NZ
dc.identifier.urihttps://hdl.handle.net/10289/4789
dc.description.abstractLake Rotoma is a deep (70-80 m), oligotrophic, warm monomictic lake of volcanic origin with insignificant stream inflow and no clearly defined outflow. For at least 60 years up to 1972 the lake level fluctuated markedly about an overall rising trend of some 6-10 m. Nearshore profiles are related to the prevailing wave climate superimposed upon the overall rising lake level, shelves being wider, less steep, and deeper about the more exposed eastern and southern shorelines. The outer portions of shelves extending well below modern storm wave base into waters as deep as 15-25 m are relict features from lower lake level stands. Sediments fine from sand-gravel mixtures nearshore to silts in basinal areas. Their composition reflects a composite provenance involving the lavas and tephras about the lake, as well as intralake diatom frustules and organic matter. The distribution pattern of surficial bottom sediments is an interplay between grains of both biological and terrigenous origin, supplied presently and in the past by a variety of processes, that have been dispersed either by the modern hydrodynamic regime or by former ones associated with lower lake levels. These interrelationships are structured by erecting 5 process-age sediment classes in the lake, namely neoteric, amphoteric, proteric, palimpsest, and relict sediments, analogous to categories postulated for sediments on oceanic continental shelves. Short-core stratigraphy includes the Kaharoa (A.D. -1020) and Tarawera (A.D. 1886) tephras. The rates of sedimentation of diatomaceous silts in basinal areas have more than doubled since the Tarawera eruption, indicating an overall increase in the fertility level of lake waters associated, perhaps, with recent farm development in the catchment.en_NZ
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherThe Royal Society of New Zealanden_NZ
dc.relation.urihttp://www.royalsociety.org.nz/publications/journals/nzjm/1983/017/en_NZ
dc.rightsThis article has been published in the journal: New Zealand Journal of Marine and Freshwater Research. © 1983 The Royal Society of New Zealand. Used with permission.en_NZ
dc.subjectLake Rotomaen_NZ
dc.subjectlakesen_NZ
dc.subjectlimnologyen_NZ
dc.subjectsedimentsen_NZ
dc.subjectsedimentationen_NZ
dc.subjectstratigraphyen_NZ
dc.subjectmorphologyen_NZ
dc.subjectsediment textureen_NZ
dc.subjectsediment collectionsen_NZ
dc.subjectsediment samplingen_NZ
dc.subjectsediment transporten_NZ
dc.subjectsediment distributionen_NZ
dc.subjectbottom topographyen_NZ
dc.titleBottom sediments of Lake Rotomaen_NZ
dc.typeJournal Articleen_NZ


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