DOI: 10.1016/j.epsl.2018.09.004
Scopus记录号: 2-s2.0-85053478338
论文题名: Lateral H2O variation in the Zealandia lithospheric mantle controls orogen width
作者: Li P. ; Scott J.M. ; Liu J. ; Xia Q.-K.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 502 起始页码: 200
结束页码: 209
语种: 英语
英文关键词: continental deformation
; mantle peridotites
; Southern Alps
; water content
Scopus关键词: Deformation
; Hydration
; Lithology
; Olivine
; Silicate minerals
; Water content
; Continental deformation
; Effective viscosity
; Fourier transform infrared spectrometry
; Lithospheric mantle
; mantle peridotites
; Oceanic lithosphere
; Peridotite xenoliths
; Southern Alps
; Fourier transform infrared spectroscopy
; Australian plate
; deformation
; mantle structure
; oceanic lithosphere
; orogeny
; Pacific plate
; peridotite
; plate boundary
; structural control
; subduction zone
; tectonic setting
; water content
; Auckland Islands
; Auckland [North Island]
; Chatham Island
; Chatham Islands
; New Zealand
; North American Cordillera
; North Island
; Otago
; South Island
; Southern Alps
英文摘要: Mantle xenoliths exhumed from beneath the South Island of New Zealand offer an opportunity to investigate the role of lithospheric mantle water in influencing deep lithosphere deformation and formation of the narrow Southern Alps mountain range during orogeny along the Australia–Pacific plate boundary. Fourier transform infrared spectrometry (FTIR) water measurements on clinopyroxene (cpx), orthopyroxene (opx) and olivine of peridotite xenoliths from seven localities across the Zealandia continent reveal a lateral variation of H2O within the Oligocene–Miocene lithospheric mantle. There is a “wet” domain beneath what is now the Southern Alps mountain range with average measured H2O concentrations of 610 ppm for cpx and 298 ppm for opx. In contrast, dominantly “dry” domains with average H2O concentrations of 110 ppm for cpx and 49 ppm for opx reside beneath East Otago, Chatham Island and Auckland Islands. Contrasting H2O concentrations within olivine (calculated to be 60 to 100 ppm for the wet domain versus <10 ppm for the dry domains) indicate a lateral gradient in mantle effective viscosity of up to one order of magnitude beneath the Southern Alps and the surrounding regions. The narrow width of the Southern Alps orogen, ∼80 km, contrasts with most of its broad counterparts worldwide, such as the North American Cordillera where the mantle was hydrated and weakened by the subduction of the Farallon plate. However, those developed orogens were often complicated by subsequent tectonic overprinting. Our findings show that the pre-existing rheologically weak zone of the mantle lithosphere, most likely resulting from hydration by the subduction of the oceanic lithosphere attached to the Australian plate beneath the South Island of New Zealand at ∼25 Ma, affects the continental deformation at or near the surface and controls the width of the developing Southern Alps orogen. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109635
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: School of Earth Sciences, Zhejiang University, Hangzhou, China; Department of Geology, University of Otago, Leith Street, Dunedin, 9054, New Zealand; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, China
Recommended Citation:
Li P.,Scott J.M.,Liu J.,et al. Lateral H2O variation in the Zealandia lithospheric mantle controls orogen width[J]. Earth and Planetary Science Letters,2018-01-01,502