Late Cretaceous crustal shortening in the northern Snake Range metamorphic core complex: Constraints on the structural geometry and magnitude of pre‐extensional footwall burial

Tectonics ◽  
2021 ◽  
Author(s):  
A. J. Wrobel ◽  
P.B. Gans ◽  
J. B. Womer
2003 ◽  
Vol 140 (4) ◽  
pp. 421-441 ◽  
Author(s):  
UWE RING ◽  
CHRISTOPHER JOHNSON ◽  
RALF HETZEL ◽  
KLAUS GESSNER

Thermochronological data reveal that the Late Cretaceous–Tertiary nappe pile of the Anatolide belt of western Turkey displays a two-stage cooling history. Three crustal segments differing in structure and cooling history have been identified. The Central Menderes metamorphic core complex represents an ‘inner’ axial segment of the Anatolide belt and exposes the lowest structural levels of the nappe pile, whereas the two ‘outer’ submassifs, the Gördes submassif to the north and the Çine submassif to the south, represent higher levels of the nappe pile. A regionally significant phase of cooling in the Late Oligocene and Early Miocene affected the outer two submassifs and the upper structural levels of the Central Menderes metamorphic core complex. In the northern part of the Gördes submassif, cooling was related to top-to-the-NNE movement on the Simav detachment, as the apatite fission-track ages show a northward-younging trend in the direction of movement on this detachment. In the Çine submassif, relatively rapid cooling in Late Oligocene and Early Miocene times may have been related to top-to-the-S extensional reactivation of the basal thrust of the overlying Lycian nappes. The second phase of cooling in the Anatolide belt is related to Pliocene to Recent extension resulting in the formation of the Central Menderes metamorphic core complex in the inner part of the Anatolide belt. Core-complex development caused the formation of supra-detachment graben, which document the ongoing separation of the Central Menderes metamorphic core complex from the outer submassifs.


2019 ◽  
Author(s):  
Michael L. Wells ◽  
◽  
Thomas Hoisch ◽  
Suzanne R. Mulligan ◽  
Samuel Wright ◽  
...  

2020 ◽  
Author(s):  
Sonia Yeung ◽  
Marnie Forster ◽  
Emmanuel Skourtsos ◽  
Gordon Lister

Abstract. 40Ar/39Ar geochronology on garnet-mica schists and the underlying Gondwanan granitoid basement terrane on Ios demonstrates evidence of a Late Cretaceous high pressure, medium temperature (HP–MP) metamorphic event. This suggests that the Asteroussia crystalline nappe on Crete may extend northward and include Ios, in the Cyclades. If this is correct, the northern part of the Asteroussia nappe (on Ios) is overlain by the terrane stack defined by the individual slices of the Cycladic Eclogite-Blueschist Unit, whereas in the south (in Crete) the Asteroussia nappe is at the top of a nappe stack defined by the individual tectonic units of the external Hellenides. This geometry implies that the accretion of the Ios basement terrane involved a significant leap (250–300 km) southwards of the surface outcrop of the subduction megathrust. This accretion would have commenced at or about ~38 Ma, when the already exhumed terranes of the Cycladic Eclogite-Blueschist Unit had begun to thrust over the Ios basement. By ~35 Ma, we suggest the subduction jump had been accomplished, and renewed rollback began the extreme extension that led to the exhumation of the Ios metamorphic core complex.


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