DOI: 10.1007/s00531-013-0894-4
论文题名: Modes of orogen-parallel stretching and extensional exhumation in response to microplate indentation and roll-back subduction (Tauern Window, Eastern Alps)
作者: Scharf A. ; Handy M.R. ; Favaro S. ; Schmid S.M. ; Bertrand A.
刊名: International Journal of Earth Sciences
出版年: 2013
卷: 102, 期: 6 起始页码: 1627
结束页码: 1654
语种: 英语
英文关键词: Indentation
; Katschberg Shear Zone System
; Lateral extrusion
; Roll-back subduction
; Stretching fault
; Tauern Window
Scopus关键词: collision zone
; exhumation
; extensional tectonics
; fault zone
; microplate
; mylonite
; normal fault
; orogeny
; Paleogene
; plate tectonics
; retrograde metamorphism
; strike-slip fault
; subduction zone
; tectonic setting
; Alps
; Eastern Alps
; Tauern Window
英文摘要: The Tauern Window exposes a Paleogene nappe stack consisting of highly metamorphosed oceanic (Alpine Tethys) and continental (distal European margin) thrust sheets. In the eastern part of this window, this nappe stack (Eastern Tauern Subdome, ETD) is bounded by a Neogene system of shear (the Katschberg Shear Zone System, KSZS) that accommodated orogen-parallel stretching, orogen-normal shortening, and exhumation with respect to the structurally overlying Austroalpine units (Adriatic margin). The KSZS comprises a ≤5-km-thick belt of retrograde mylonite, the central segment of which is a southeast-dipping, low-angle extensional shear zone with a brittle overprint (Katschberg Normal Fault, KNF). At the northern and southern ends of this central segment, the KSZS loses its brittle overprint and swings around both corners of the ETD to become subvertical, dextral, and sinistral strike-slip faults. The latter represent stretching faults whose displacements decrease westward to near zero. The kinematic continuity of top-east to top-southeast ductile shearing along the central, low-angle extensional part of the KSZS with strike-slip shearing along its steep ends, combined with maximum tectonic omission of nappes of the ETD in the footwall of the KNF, indicates that north-south shortening, orogen-parallel stretching, and normal faulting were coeval. Stratigraphic and radiometric ages constrain exhumation of the folded nappe complex in the footwall of the KSZS to have begun at 23-21 Ma, leading to rapid cooling between 21 and 16 Ma. This exhumation involved a combination of tectonic unroofing by extensional shearing, upright folding, and erosional denudation. The contribution of tectonic unroofing is greatest along the central segment of the KSZS and decreases westward to the central part of the Tauern Window. The KSZS formed in response to the indentation of wedge-shaped blocks of semi-rigid Austroalpine basement located in front of the South-Alpine indenter that was part of the Adriatic microplate. Northward motion of this indenter along the sinistral Giudicarie Belt offsets the Periadriatic Fault and triggered rapid exhumation of orogenic crust within the entire Tauern Window. Exhumation involved strike-slip and normal faulting that accommodated about 100 km of orogen-parallel extension and was contemporaneous with about 30 km of orogen-perpendicular, north-south shortening of the ETD. Extension of the Pannonian Basin related to roll-back subduction in the Carpathians began at 20 Ma, but did not affect the Eastern Alps before about 17 Ma. The effect of this extension was to reduce the lateral resistance to eastward crustal flow away from the zone of greatest thickening in the Tauern Window area. Therefore, we propose that roll-back subduction temporarily enhanced rather than triggered exhumation and orogen-parallel motion in the Eastern Alps. Lateral extrusion and orogen-parallel extension in the Eastern Alps have continued from 12 to 10 Ma to the present and are driven by northward push of Adria. © 2013 Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881614555&doi=10.1007%2fs00531-013-0894-4&partnerID=40&md5=2cf753fbc4615cbb25797192416d6a96
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70527
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: Department of Earth Sciences, Freie Universität Berlin, Malteserstrasse 74-100, 12249 Berlin, Germany; Department of Geophysics, Eidgenössische Technische Hochschule (ETH), Sonneggstrasse 5, 8092 Zurich, Switzerland; alps GmbH, Center for Climate Change and Adaptation Technologies, Grabenweg 68, 6020 Innsbruck, Austria
Recommended Citation:
Scharf A.,Handy M.R.,Favaro S.,et al. Modes of orogen-parallel stretching and extensional exhumation in response to microplate indentation and roll-back subduction (Tauern Window, Eastern Alps)[J]. International Journal of Earth Sciences,2013-01-01,102(6)