科研之友
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摘要
The processes that drastically thinned and rapidly exhumed the Alboran Domain in southern Spain are poorly understood. Geological maps, cross-sections and a synthesis of previous work in the Alpujarride Complex provide a new structural framework for the Alboran Domain, with major revision of the previously defined lithotectonic units. Alboran continental lithosphere was buried and thickened in the Paleogene (D-1) and subsequently thinned during late-orogenic extension in the early Miocene. Regional patterns of stretching lineations and late recumbent folds record important spatiotemporal changes in the kinematics of extension. East-directed shear (D-2) is preserved in deep orogenic levels and thinned the crustal sequence during rapid exhumation and high-temperature metamorphism. North-directed shear (D-3/D-4) is preserved in upper orogenic levels and reworked earlier structures during the later stages of exhumation and cooling. This large-scale switch in the direction of finite stretching resulted from the interaction between components of orogen-parallel (D-2) and orogen-perpendicular (D-3/D-4) extension, and associated vertical and lateral gradients in strain. We provide a novel kinematic model for gravity-driven extensional collapse of the Alboran Domain, compatible with both westward motion of the Alboran Domain relative to the Iberian margin and subsequent northward extensional flow and emplacement of Alboran lithosphere onto the Iberian margin.
- 出版日期2018-5
