Tectonic implications of early Miocene extensional unroofing of the Sierra Mazatán metamorphic core complex, Sonora, Mexico

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.

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Genesis of the Hongzhen metamorphic core complex and its tectonic implications

Science in China Series D Earth Sciences ◽

10.1007/s11430-007-0032-x ◽

2007 ◽

Vol 50 (5) ◽

pp. 649-659 ◽

Cited By ~ 5

Author(s):

Guang Zhu ◽

ChengLong Xie ◽

BiWei Xiang ◽

ZhaoQi Hu ◽

YongSheng Wang ◽

...

Keyword(s):

Metamorphic Core Complex ◽

Core Complex ◽

Tectonic Implications ◽

Metamorphic Core

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Evolution of the Yiwulushan metamorphic core complex from distributed to localized deformation and its tectonic implications

Tectonics ◽

10.1029/2012tc003104 ◽

2012 ◽

Vol 31 (4) ◽

pp. n/a-n/a ◽

Cited By ~ 30

Author(s):

Bilong Zhang ◽

Guang Zhu ◽

Dazhi Jiang ◽

Changcheng Li ◽

Yin Chen

Keyword(s):

Metamorphic Core Complex ◽

Localized Deformation ◽

Core Complex ◽

Tectonic Implications ◽

Metamorphic Core

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Supplemental Material: Evidence of Early Miocene synextensional volcanism and deposition in the northern Calico Mountains, central Mojave metamorphic core complex, southern California, USA

10.1130/geos.s.14342510.v1 ◽

2021 ◽

Author(s):

B.P. Murray ◽

W.E. Hames

Keyword(s):

Southern California ◽

Metamorphic Core Complex ◽

Early Miocene ◽

Font Size ◽

Core Complex ◽

Analytical Results ◽

Metamorphic Core ◽

Material Evidence

<div>40Ar/<sup>39</sup>Ar analytical results. "}" data-sheets-userformat="{"2":893,"3":{"1":0},"5":{"1":[{"1":2,"2":0,"5":{"1":2,"2":0}},{"1":0,"2":0,"3":3},{"1":1,"2":0,"4":1}]},"6":{"1":[{"1":2,"2":0,"5":{"1":2,"2":0}},{"1":0,"2":0,"3":3},{"1":1,"2":0,"4":1}]},"7":{"1":[{"1":2,"2":0,"5":{"1":2,"2":0}},{"1":0,"2":0,"3":3},{"1":1,"2":0,"4":1}]},"8":{"1":[{"1":2,"2":0,"5":{"1":2,"2":0}},{"1":0,"2":0,"3":3},{"1":1,"2":0,"4":1}]},"9":0,"11":3,"12":0}" style="font-size: 10pt; font-family: Arial;">Table S1: <sup>40</sup>Ar/<sup>39</sup>Ar analytical results.<br></div>

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Supplemental Material: Evidence of Early Miocene synextensional volcanism and deposition in the northern Calico Mountains, central Mojave metamorphic core complex, southern California, USA

10.1130/geos.s.14342510 ◽

2021 ◽

Author(s):

B.P. Murray ◽

W.E. Hames

Keyword(s):

Southern California ◽

Metamorphic Core Complex ◽

Early Miocene ◽

Font Size ◽

Core Complex ◽

Analytical Results ◽

Metamorphic Core ◽

Material Evidence

<div>40Ar/<sup>39</sup>Ar analytical results. "}" data-sheets-userformat="{"2":893,"3":{"1":0},"5":{"1":[{"1":2,"2":0,"5":{"1":2,"2":0}},{"1":0,"2":0,"3":3},{"1":1,"2":0,"4":1}]},"6":{"1":[{"1":2,"2":0,"5":{"1":2,"2":0}},{"1":0,"2":0,"3":3},{"1":1,"2":0,"4":1}]},"7":{"1":[{"1":2,"2":0,"5":{"1":2,"2":0}},{"1":0,"2":0,"3":3},{"1":1,"2":0,"4":1}]},"8":{"1":[{"1":2,"2":0,"5":{"1":2,"2":0}},{"1":0,"2":0,"3":3},{"1":1,"2":0,"4":1}]},"9":0,"11":3,"12":0}" style="font-size: 10pt; font-family: Arial;">Table S1: <sup>40</sup>Ar/<sup>39</sup>Ar analytical results.<br></div>

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Stratigraphic and Sedimentologic Response to the Evolution of a Metamorphic Core Complex: an Example from the Early Miocene Mojave Extensional Belt, California

AAPG Bulletin ◽

10.1306/d9cb5a39-1715-11d7-8645000102c1865d ◽

1993 ◽

Vol 77 ◽

Author(s):

JONES, STEVEN M., and CHRISTOPHER J

Keyword(s):

Metamorphic Core Complex ◽

Early Miocene ◽

Core Complex ◽

Metamorphic Core

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Evidence of early Miocene synextensional volcanism and deposition in the northern Calico Mountains, central Mojave metamorphic core complex, southern California, USA

Geosphere ◽

10.1130/ges02356.1 ◽

2021 ◽

Author(s):

Bryan P. Murray ◽

Willis E. Hames

Keyword(s):

Debris Flow ◽

Southern California ◽

Hanging Wall ◽

Metamorphic Core Complex ◽

Early Miocene ◽

Core Complex ◽

Alluvial Deposits ◽

Mafic Lava ◽

Lapilli Tuff ◽

Metamorphic Core

The spatiotemporal link between large-scale continental crustal extension and magmatic activity has been identified by numerous past studies, yet commonly the details of these associations remain unresolved. This study in the central Mojave metamorphic core complex (CMMCC) of southern California (USA) presents new geologic mapping, stratigraphic interpretations, and 40Ar/39Ar geochronology of the Jackhammer and Pickhandle Formations in the northern Calico Mountains to provide additional age constraints on the relative timing of early Miocene volcanism, deposition, and extension. The Jackhammer Formation, the oldest Tertiary stratigraphic unit, is nonconformable with pre-Cenozoic nonmylonitic metasedimentary and plutonic basement rocks and consists primarily of alluvial deposits and primary to reworked silicic tuffs, interbedded locally with basement-derived avalanche megabreccia, lacustrine limestone, and mafic lava; in addition, the “Mammut ignimbrite”, an ~130-m-thick crystal-rich welded lapilli tuff, is exposed only in the eastern part of the study area and appears to transition laterally into thinner, nonwelded lapilli tuff ~6 km to the west. The Pickhandle Formation conformably overlies the Jackhammer Formation and consists of: (1) a lower assemblage composed of reddish monomictic debris-flow breccias with porphyritic rhyodacitic clasts and silicic block-and-ash-flow deposits of similar composition; and (2) an upper assemblage of polymictic (metaplutonic basement and rhyodacite) alluvial deposits, primary to reworked lapilli tuff, and local rhyodacitic lava and block-and-ash flows. Rhyodacitic lava domes were emplaced during the final stages of Pickhandle Formation deposition, primarily intruded along preexisting normal fault zones. Sedimentary and volcanic lithofacies suggest that the Jackhammer and Pickhandle Formations were deposited in a volcanic vent–proximal alluvial fan system that formed within a half-graben basin bounded on the east by the southwest-dipping “Amphitheatre fault”. Growth strata within the hanging-wall deposits, primarily southwest-directed paleocurrents, and interbedded alluvial debris-flow, basement-derived megabreccia, and lacustrine deposits adjacent to this fault suggest synextensional deposition in an intra-hanging-wall basin that developed during upper-plate extension in the CMMCC. New 40Ar/39Ar ages for six samples of silicic pyroclastic flows and a lava dome from the synextensional Pickhandle and Jackhammer Formations in the Calico Mountains have a mean age of 20.10 ± 0.06 Ma. This age is 3–4 m.y. younger than the maximum age of initial extension determined by previous studies in other areas of the central Mojave, suggesting that CMMCC extension was not a synchronous large-magnitude regional event. Rather, extension and contemporaneous volcanism was more localized and asynchronous across the region, occurring in many smaller extensional basins that eventually culminated in exposure of the CMMCC mylonitic footwall rocks.

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