Correlating deformation and metamorphism around orogenic arcs

Bell, T. H.; Mares, V. M.

doi:10.2138/am-1999-11-1203

Cited by 53 publications

(28 citation statements)

References 15 publications

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“…It also only allows one or two generations of growth of the same porphyroblastic phase to be recognized. The FIA method provides a quantitative tool to distinguish and correlate multiple generations of porphyroblasts over large distances (Bell and Mares, 1999). Combined with in situ dating of the inclusion trails that define a FIA set, this provides detailed insights into tectono-metamorphic histories that were previously difficult to unravel.…”

Section: Discussion and Significancesupporting

confidence: 90%

The problem, significance and implications for metamorphism of 60 million years of multiple phases of staurolite growth

Sanislav

Shah

2010

J Geol Soc India

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Microstructural measurements of FIAs in staurolite reveal at least 3 periods of growth in the Proterozoic Colorado Front Range and 5 in the Paleozoic Western Maine. Dated monazite inclusions in staurolite have an absolute age of 1760±12 Ma (FIA 1), 1720±7 Ma (FIA 2), 1682±18 Ma (FIA 3) in Colorado, and 408±10 Ma (FIA 2), 388±8 Ma (FIA 3), 372±6 Ma (FIA 4), 352±4 Ma (FIA 5) in Maine, supporting the multiple periods of deformation and metamorphism indicated by the FIA succession in each region. Multiple phases of growth by similar reactions in the same as well as in diverse adjacent rocks in both regions suggest that PT and X are not the only factors controlling the commencement and cessation of metamorphic reactions. The FIAs preserved by the staurolite porphyroblasts indicate that the local partitioning of deformation at the scale of a porphyroblast was the eventual controlling factor on whether or not the staurolite forming reactions took place.

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Section: Discussion and Significancesupporting

confidence: 90%

The problem, significance and implications for metamorphism of 60 million years of multiple phases of staurolite growth

Sanislav

Shah

2010

J Geol Soc India

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“…SSITs appear so obviously a product of rotation of the porphyroblast within a foliation as progressive shearing occurred that no one considered the possibility that this might not be the case until the 1980s. However, a technique for quantitatively measuring the axes of SSITs was developed (Hayward, 1990;Bell, Forde & Wang, 1995) and a large amount of data has now been published on the orientation of spiral axes around folds (Bell & Hickey, 1997;Hickey & Bell, 2001;Bell & Chen, 2002;Timms, 2004), around oroclines (Bell & Mares, 1999;Yeh & Bell, 2004) and along and across orogens (Bell & Bruce, 2006;Bell, Hickey & Upton, 1998;Bell, Ham & Hickey, 2003, Bell, Ham & Kim, 2004Bell et al 2005;Cihan, 2004;Cihan & Parsons, 2005). He also generated a non-coaxial strain field diagram that mimicked asymmetric crenulation cleavages and straight to slightly sigmoidal inclusion trails that are common in so many porphyroblasts.…”

Section: E Alpine Top-to-the-s Shearing During Main Menderes Metammentioning

confidence: 99%

Extensional v. contractional origin for the southern Menderes shear zone, SW Turkey: tectonic and metamorphic implications

Bozkurt

2006

Geol. Mag.

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The southern Menderes Massif in southwest Turkey consists mainly of orthogneisses and overlying Palaeozoic-Middle Paleocene schists and marbles. The contact between the two distinct rock types is almost everywhere structural, herein named the southern Menderes shear zone: a S-facing, high-angle ductile shear zone that separates metamorphic rocks of differing grade. Although there is a consensus that the shear zone was associated with top-to-the-S-SSW shearing and is of Tertiary age, its origin and nature have been highly debated over the last decade. Some claim the contact is a thrust fault, while others have argued for an extensional shear zone. Integration of field and microstructural data (the identification of different fabrics, associated kinematics and overprinting relationships) with fissiontrack thermochronology and the P-T paths of the rocks above and below the shear zone, supports the conclusion that the southern Menderes shear zone is an extensional shear zone and not a thrust. The data are consistent with a model that the exhumation and cooling of the southern Menderes Massif occurred after a period of extensional deformation. Pervasive top-to-the-N-NNE high-temperature-mediumpressure ductile shear structures (D 2 deformation) overprint an early HP event (D 1 deformation). The subsequent top-to-the-S-SSW greenschist shear band foliation (D 3 deformation) developed mostly around the orthogniess-schist contact and forms the most characteristic features of the massif. The topto-the-N-NNE structures are attributed to the main Alpine constructional deformation that developed during back-thrusting of the Lycian nappes during the latest Palaeogene collision between the Sakarya continent and the Anatolide-Tauride platform across the Neotethyan Ocean. The top-to-the-S-SSW structures are interpreted to be the result of the exhumation of the massif during the activity of the southern Menderes shear zone. The presence of these two distinct fabrics with differing kinematics suggests that the southern Menderes shear zone operated as a top-to-the-N-NNE thrust fault during early Alpine contractional deformation but was later reactivated with an opposite sense of movement (top-to-the-S-SSW) during subsequent Oligocene-Miocene extensional collapse.

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“…For example, Bell and co-workers have suggested that in a number of orogenic belts, foliations appear to have formed during repeated episodes of convergence and extension that can be correlated over large distances (e.g. Bell & Mares 1999). In some instances, these episodes appear to have occurred within the time scale of a single metamorphic cycle.…”

Section: Continental Reworkingmentioning

confidence: 99%