DOI: 10.1007/s00531-012-0796-x
论文题名: Post-glacial time series of explosive eruptions and associated changes in the magma plumbing system of Lonquimay volcano, south central Chile
作者: Gilbert D. ; Freundt A. ; Kutterolf S. ; Burkert C.
刊名: International Journal of Earth Sciences
出版年: 2014
卷: 103, 期: 7 起始页码: 2043
结束页码: 2062
语种: 英语
英文关键词: Eruption time series
; Magma storage
; Probabilistic eruption forecast
; Southern Volcanic Zone
; Tephrochronology
; Thermobarometry
; Volcanic hazards
Scopus关键词: explosive volcanism
; geobarometry
; magma chamber
; pyroclastic deposit
; tephrochronology
; time series analysis
; volcanic eruption
; Araucania
; Lonquimay Volcano
; Southern Volcanic Zone
; Southern Volcanic Zone
英文摘要: The Lonquimay volcanic complex (LVC) in the high Southern Andes comprises a stratocone and NE-trending flank-cone alignments. Numerous effusive and explosive volcanic eruptions characterize its post-glacial magmatic activity. Our tephrostratigraphic record, pre-dating the four historically documented eruptions, comprises 22 dated pyroclastic deposits that are used to constrain repose time distribution and eruption probability of the LVC magmatic system. Statistical examination of the stratigraphy-based eruption time series yields probabilities of 20–50 % for at least one explosive (VEI ≥ 3) eruption within the next 100 years as of 2011. The tephra deposits are subdivided into three petrographic groups: a felsic group (Lonquimay colored-pumice tephra, LCPT), an intermediate population (Lonquimay gray pumice tephra, LGPT), and a mafic member (Lonquimay dark scoria tephra, LDST). The distribution of these petrographic groups through the LVC tephrostratigraphy is linked to the observed changes in repose times. LDST-deposits as well as deposits compositionally zoned from LCPT to LGPT dominate the lower part of the stratigraphy for which recurrence times are short (RTmean = 417 ± 169a). Deposits younger than 6,000 b2k (years before 2000 AD) have dominantly LCPT and minor LDST compositions, no longer contain LGPT, and repose times are significantly longer (RTmean = 1,350 ± 310a). We interpret the change in eruption regime to result from a rearrangement in the magma storage and plumbing system. Thermobarometric calculations based on cpx–liquid equilibria and amphibole compositions reveal three distinct magma storage levels: the mafic LDST derive from mid crustal storage (Pmean = 476 ± 95 MPa, Tmean = 1,073 ± 24 °C), felsic LCPT mainly erupted from upper-crustal level (Pmean = 86 ± 49 MPa, Tmean = 936 ± 24 °C), whereas LGPT samples yield intermediate storage depths (Pmean = 239 ± 100 MPa, Tmean = 1,013 ± 17 °C). Magma contributions from this intermediate reservoir are restricted to >6,000 b2k when the Lonquimay plumbing system was in a regime of short repose times; disappearance of the intermediate reservoir coincides with the change to longer repose times between eruptions. © 2012, Springer-Verlag. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896799261&doi=10.1007%2fs00531-012-0796-x&partnerID=40&md5=a429c197b19e32bfc5ce17b7a1bbdded
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70336
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: SFB 574 at GEOMAR, Wischhofstr. 1-3, Kiel, Germany; GEOMAR, Wischhofstr. 1-3, Kiel, Germany
Recommended Citation:
Gilbert D.,Freundt A.,Kutterolf S.,et al. Post-glacial time series of explosive eruptions and associated changes in the magma plumbing system of Lonquimay volcano, south central Chile[J]. International Journal of Earth Sciences,2014-01-01,103(7)