Sedimentology of latero-frontal moraines and fans on the west coast of South Island, New Zealand

Evans, David J. A., Shulmeister, James and Hyatt, Olivia (2010) Sedimentology of latero-frontal moraines and fans on the west coast of South Island, New Zealand. Quaternary Science Reviews, 29 27-28: 3790-3811. doi:10.1016/j.quascirev.2010.08.019

Author Evans, David J. A.
Shulmeister, James
Hyatt, Olivia
Title Sedimentology of latero-frontal moraines and fans on the west coast of South Island, New Zealand
Journal name Quaternary Science Reviews   Check publisher's open access policy
ISSN 0277-3791
Publication date 2010-11-01
Year available 2010
Sub-type Article (original research)
DOI 10.1016/j.quascirev.2010.08.019
Open Access Status
Volume 29
Issue 27-28
Start page 3790
End page 3811
Total pages 22
Place of publication Oxford, United Kingdom
Publisher Pergamon
Language eng
Formatted abstract
Exposures through the LGM latero-frontal moraine loops at sites along the west coast of South Island, New Zealand reveal a depositional environment that was dominated by the progradation of steep fronted, debris flow-fed fans, manifest in crudely stratified to massive diamictons, arranged in sub-horizontal to steeply dipping clinoforms and containing discontinuous bodies of variably sorted, stratified sediment (LFA 1). The fans were constructed by debris-covered glaciers advancing over outwash plains, as recorded by well stratified and horizontally bedded gravels, sands and diamicts (LFA 0). The ice-contact slopes of the fans are offlapped by retreat phase deposits in the form of glacilacustrine depo-centres (LFA 2), which record the existence of moraine-dammed lakes. Interdigitation of lake rhythmites and subaerial to subaqueous sediment gravity flow deposits documents intense debris-flow activity on unstable moraine/fan surfaces. Glacier readvances in all catchments are documented by glacitectonic disturbance and localized hydrofracturing of LFA 2, followed by the emplacement of schist-dominated debris flow-fed fans (LFA 3) inside and over the top of the earlier latero-frontal moraine/fan loops. Contorted and disturbed bedding in LFA 3 reflects its partial deposition in supraglacial positions. Clast lithologies in LFAs 1 and 3 reveal that two distinct transport pathways operated during moraine construction, with an early period of latero-frontal fan construction involving mixed lithologies and a later period of ice-contact/supraglacial fan construction dominated by schist lithologies from the mountains. These two periods of deposition were separated by a period of moraine abandonment and paraglacial reworking of ice-contact slopes to produce LFA 2. The occurrence of LFA 3 at all sites indicates that the glacier readvance phase responsible for its deposition was not localized or glacier-specific, and involved the transfer of large volumes of schist, possibly due to rock slope failures, onto glacier surfaces. The absence of any sediment that could be unequivocally classified as subglacial till reflects the dominance of debris flow and glacifluvial processes in latero-frontal moraine construction in this hyper-humid west coast setting.
© 2010 Elsevier Ltd.
Keyword Debris flows
Debris-covered glacier
Depositional environment
Moraine-dammed lake
Outwash plains
Rock slope failure
Sediment gravity flow
South Island
New Zealand
Transport pathways
West coast
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Geography, Planning and Environmental Management Publications
Official 2011 Collection
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Citation counts: TR Web of Science Citation Count  Cited 15 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 16 times in Scopus Article | Citations
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Created: Fri, 10 Dec 2010, 01:48:56 EST by Professor James Shulmeister on behalf of School of Geography, Planning & Env Management