Fault Block Rotations in Ophiolites: Results of Palaeomagnetic Studies in the Troodos Complex, Cyprus

Allerton, Simon

doi:10.1007/978-94-009-0869-7_24

Cited by 19 publications

(21 citation statements)

References 22 publications

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“…In this model, plate separation was at least partly accommodated by tectonic thinning of the upper crust during periods of amagmatic stretching. Palaeomagnetic analysis of these dykes (Allerton & Vine 1987;Allerton 1989a;Hurst et aI. 1992) confirms that they were originally intruded in (sub)vertical orientations.…”

Section: T R O O D O S Ophiolitementioning

confidence: 51%

“…The former regions (stereonets 1 4 with unshaded ~95 ellipses in Fig. 4) are the northern margin of the main ophiolite (Clube 1985), the Solea region (Allerton & Vine 1987;Allerton 1989a;Hurst et al 1992), the Akamas peninsula (Clube 1985;Morris et al 1998) and the western margin of the ophiolite (Morris et al 1998). These regions are remote from the STTFZ and its inferred westerly along-strike extension, and provide the evidence for the ophiolite-wide bulk anticlockwise rotation of the Troodos microplate first identified from natural remanent magnetization data by Vine & Moores (1969) and Moores & Vine (1971).…”

Section: T R O O D O S Ophiolitementioning

confidence: 99%

“…An alternative net tectonic rotation approach that has been widely adopted in these ophiolites (Allerton & Vine 1987;Allerton 1989a;Morris et al 1990Morris et al , 1998Hurst et al 1992) is to describe the deformation at a site in terms of a single rotation about an inclined axis, which restores both the palaeohorizontal and palaeovertical to their initial orientation and the site mean magnetization vector to the appropriate palaeomagnetic reference direction. This single rotation may then be decomposed into any number of component rotations on the basis of additional structural data, and/or net tectonic rotation axes may be interpreted directly in terms of structural history.…”

Section: Data Correction and Interpretation Techniquesmentioning

confidence: 99%

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Palaeomagnetic insights into the evolution of Neotethyan oceanic crust in the eastern Mediterranean

Morris

Anderson

Inwood

et al. 2006

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A synopsis of palaeomagnetic data from three Late Cretaceous eastern Mediterranean Tethyan ophiolites (Troodos, Hatay and Ba6r-Bassit) and their sedimentary cover sequences is presented. These data provide valuable insights into the role of regional-and local-scale tectonic rotations in the geodynamic evolution of Neotethyan oceanic crust. The geologically earliest phases of tectonic rotation are documented in the Troodos ophiolite, where rotations around both subvertical and subhorizontal axes are readily related to the development of the spreading fabrics and structures during crustal genesis. Subsequent c. 74 ~ anticlockwise intra-oceanic rotation of a 'Troodos microplate' has been quantified through analysis of the in situ sedimentary cover of the Troodos ophiolite. Results indicate that bulk anticlockwise rotation began soon after the cessation of spreading and ended by the end of the Eocene, with c. 50-60 ~ of microplate rotation being over by the Maastrichtian, the time at which ophiolite thrust sheets were emplaced onto the Arabian continental margin to the east of Troodos. Recent results from the emplaced, structurally dismembered Ba6r-Bassit ophiolite indicate extreme anticlockwise rotations of ophiolitic thrust sheets varying on a kilometre scale. New data from the post-emplacement sedimentary cover confirm that only a small component of these rotations is due to post-emplacement tectonism. Ba6r-Bassit represents the leading edge of the emplaced ophiolitic sheet. New data from the more coherent section preserved in the Hatay ophiolite to the north demonstrate significant anticlockwise rotation. This is equivalent to the rotation of the most northerly part of the Ba6r-Bassit units to the south, and is of the same sense and magnitude as the preMaastrichtian phase of microplate rotation documented in the Troodos. This suggests a common, intra-oceanic origin for the majority of the Troodos and Hatay rotations, and a significant component of the more variable rotations observed in Ba~Bassit. Overall, therefore, the data support a model involving: (1) intra-oceanic rotation of a coherent region of crust within the southern Neotethyan basin; this rotated unit is more areally extensive than has previously been inferred from consideration of data from the Troodos ophiolite alone; (2) emplacement of part of the rotated unit onto the Arabian platform; (3) subsequent localized post-emplacement modification, related to the development of the current plate configuration.

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Section: T R O O D O S Ophiolitementioning

confidence: 51%

Section: T R O O D O S Ophiolitementioning

confidence: 99%

Section: Data Correction and Interpretation Techniquesmentioning

confidence: 99%

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Palaeomagnetic insights into the evolution of Neotethyan oceanic crust in the eastern Mediterranean

Morris

Anderson

Inwood

et al. 2006

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“…The location of the Solea graben was originally constrained by the orientation of normal faults, opposing tilt of sheeted dikes, and rotated blocks of lava flow [Hurst et al, 1994]. Paleomagnetic study of the gabbroic suite [Granot et al, 2006] confirmed the location of the suspected paleospreading Solea axis and showed a clockwise rotation of remanence directions in the inside corner north of the Arakapas Transform fault ( Figure S1 in the auxiliary material), similar to the rotations shown for the overlying sheeted dikes [Allerton, 1989;Bonhommet et al, 1988], pillow lavas and hydrothermal sediments (umbers) [Morris et al, 1990]. …”

Section: Tectonic Settingmentioning

confidence: 64%

Direct evidence for dynamic magma supply fossilized in the lower oceanic crust of the Troodos ophiolite

Granot

Abelson

Ron

et al. 2011

Geophys. Res. Lett.

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Temporal and spatial variabilities of mantle upwelling and melt supply in mid‐ocean ridges (MORs) have long been documented. Such variabilities span a range of scales and have a profound effect on the structure as well as the composition of the oceanic crust. Previous seismic and gravity studies have suggested that the lower oceanic crust plays a major role in accommodating these changes in melt supply. Here we report the first direct evidence for a sharp transition from coherent sub‐horizontal to near vertical magma flows frozen in the lower oceanic crust of the Troodos ophiolite at the segment edge near a fossil ridge‐transform intersection. We constrain the preferred petrofabric lineation directions at 13 gabbroic sites using anisotropy of magnetic susceptibility (AMS) verified by electron backscatter diffraction. Pre‐emplacement accretion‐related rotations were corrected using magnetic remanence directions. We identify two provinces of nearly uniform susceptibility directions (principal axes) and attribute them to two magmatic episodes. A more focused mantle upwelling and melting episode near the segment midpoint may have resulted in lower crustal lateral magma flows along the fossil segment‐edge, whereas uniform mantle upwelling and melt supply along the entire axis may have resulted in vertical magma flows at the segment‐edge. Overall, our data verify the vital role of the lower oceanic crust in accommodating changes in mantle upwelling and melt supply beneath MORs.

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“…2). Several procedures are suggested for untilting sheeted dikes (Bonhommet and Calza, 1988;Allerton, 1989). The most commonly used method involves plotting the rotational axis on a stereo net.…”

Section: Sheeted Dike Complexmentioning

confidence: 99%

Structures and microstructures related to steady-state mantle flow in the Neyriz ophiolite, Iran

Sarkarinejad

2005

Journal of Asian Earth Sciences

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Fault Block Rotations in Ophiolites: Results of Palaeomagnetic Studies in the Troodos Complex, Cyprus

Cited by 19 publications

References 22 publications

Palaeomagnetic insights into the evolution of Neotethyan oceanic crust in the eastern Mediterranean

Palaeomagnetic insights into the evolution of Neotethyan oceanic crust in the eastern Mediterranean

Direct evidence for dynamic magma supply fossilized in the lower oceanic crust of the Troodos ophiolite

Structures and microstructures related to steady-state mantle flow in the Neyriz ophiolite, Iran

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