DOI: 10.1016/j.quascirev.2015.06.014
Scopus记录号: 2-s2.0-84934901465
论文题名: Tools and techniques for developing tephra stratigraphies in lake cores: A case study from the basaltic Auckland Volcanic Field, New Zealand
作者: Hopkins J.L. ; Millet M.-A. ; Timm C. ; Wilson C.J.N. ; Leonard G.S. ; Palin J.M. ; Neil H.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2015
卷: 123 起始页码: 58
结束页码: 75
语种: 英语
英文关键词: Auckland Volcanic Field
; Basalt
; Geochemistry
; Lake cores
; Magnetic susceptibility
; Tephra
; Tephra reworking
; Tephrostratigraphy
; X-ray density scanning
Scopus关键词: Basalt
; Deposits
; Gadolinium
; Geochemistry
; Glass
; Lakes
; Magnetic susceptibility
; Neodymium
; Stratigraphy
; Trace elements
; Volcanoes
; Ytterbium
; Tephra
; Tephra reworking
; Tephrostratigraphy
; Volcanic field
; X-ray density
; Zirconium
; basalt
; correlation
; forecasting method
; geochemistry
; hazard assessment
; historical record
; lacustrine deposit
; magnetic susceptibility
; reconstruction
; reworking
; rhyolite
; tephra
; tephrochronology
; trace element
; volcanic eruption
; volcanic glass
; X-ray spectroscopy
; Auckland
; Auckland Volcanic Field
; New Zealand
; North Island
英文摘要: Probabilistic hazard forecasting for a volcanic region relies on understanding and reconstructing the eruptive record (derived potentially from proximal as well as distal volcanoes). Tephrostratigraphy is commonly used as a reconstructive tool by cross-correlating tephra deposits to create a stratigraphic framework that can be used to assess magnitude-frequency relationships for eruptive histories. When applied to widespread rhyolitic deposits, tephra identifications and correlations have been successful; however, the identification and correlation of basaltic tephras are more problematic. Here, using tephras in drill cores from six maars in the Auckland Volcanic Field (AVF), New Zealand, we show how X-ray density scanning coupled with magnetic susceptibility analysis can be used to accurately and reliably identify basaltic glass shard-bearing horizons in lacustrine sediments and which, when combined with the major and trace element signatures of the tephras, can be used to distinguish primary from reworked layers. After reliably identifying primary vs. reworked basaltic horizons within the cores, we detail an improved method for cross-core correlation based on stratigraphy and geochemical fingerprinting. We present major and trace element data for individual glass shards from 57 separate basaltic horizons identified within the cores. Our results suggest that in cases where major element compositions (SiO2 , CaO, Al2 O3 , FeO, MgO) do not provide unambiguous correlations, trace elements (e.g. La, Gd, Yb, Zr, Nb, Nd) and trace element ratios (e.g. [La/Yb]N , [Gd/Yb]N , [Zr/Yb]N ) are successful in improving the compositional distinction between the AVF basaltic tephra horizons, thereby allowing an improved eruptive history of the AVF to be reconstructed. © 2015 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59861
Appears in Collections: 过去全球变化的重建
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作者单位: School of Geography, Environment and Earth Sciences, Victoria University, PO Box 600, Wellington, New Zealand; Department of Earth Sciences, Durham University, Durham, England, United Kingdom; GNS Science, PO Box 30368, Lower Hutt, New Zealand; Department of Geology, University of Otago, PO Box 56, Dunedin, New Zealand; National Institute of Water and Atmospheric Research, PO Box 14-911, Wellington, New Zealand
Recommended Citation:
Hopkins J.L.,Millet M.-A.,Timm C.,et al. Tools and techniques for developing tephra stratigraphies in lake cores: A case study from the basaltic Auckland Volcanic Field, New Zealand[J]. Quaternary Science Reviews,2015-01-01,123