Strain and possible volume loss in a high-grade ductile shear zone

Srivastava, H. K.; Hudleston, Peter J.; Earley, Drummond

doi:10.1016/0191-8141(95)00025-9

Cited by 35 publications

(10 citation statements)

References 47 publications

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“…Often the evidence for volume loss is equivocal (Simpson, 1981;Mohanty and Ramsay, 1994), and in some cases, volume loss can be discounted (Srivastava et al, 1995;Bhattacharyya and Hudleston, 2001). If conditions for deformation are isochoric (constant volume), then lateral displacement of shear zone material must occur and the shear zone will narrow.…”

Section: Dextral Transpressional Eventmentioning

confidence: 95%

Implications of strain and vorticity of flow analyses to interpret the kinematics of an oblique convergence event (Zagros Mountains, Iran)

Sarkarinejad

Samani

Faghih

et al. 2010

Journal of Asian Earth Sciences

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Section: Dextral Transpressional Eventmentioning

confidence: 95%

Implications of strain and vorticity of flow analyses to interpret the kinematics of an oblique convergence event (Zagros Mountains, Iran)

Sarkarinejad

Samani

Faghih

et al. 2010

Journal of Asian Earth Sciences

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“…Ramsay and Graham 1970). Several studies have invoked the synchronous occurrence of simple shear, pure shear, and volume change to explain natural heterogeneous shear zones (De Paor 1988;Srivastava et al 1995;Ring 1998;Baird and Hudleston 2007), which suggest that deformation in the most ductile detachment zones is not strictly progressive simple shear but includes a component of pure shear (coaxial flow). Kinematic vorticity is an effective method to estimate the components of simple shear and pure shear and has been widely applied to many fields, such as the analysis of single shear zones (Simpson and De Paor 1993;Forte and Bailey 2007;Jessup et al 2007;Iredale et al 2013), the tectonic evolution of orogen (Klepeis et al 1999;Doutsos 2000, 2001), and the mechanisms of metamorphic core complexes (MCCs) and extensional structures .…”

Section: Introductionmentioning

confidence: 95%

Formation of Late Jurassic–Early Cretaceous metamorphic core complexes in Northeast China: insight from a structural study of the Yiwulüshan ductile detachment zone

Wang

Guo

et al. 2016

International Geology Review

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Late Jurassic to Early Cretaceous extensional structures are widespread in Northeast China and the eastern part of the Asian continent. The Yiwulüshan ductile detachment shear zone, the master ductile detachment zone of the Yiwulüshan metamorphic core complex (MCC), occurs in the northern North China Craton. This shear zone dips to the northwest on the western flank and to the southeast on the eastern flank of the MCC and consists of brittle faults, breccia, chloritized microbreccia, and ductile (mylonite) zones. The well-developed mylonitic foliation and stretching lineation are characterized by oriented minerals (quartz and feldspar) that exhibit ductile deformation, including undulose extinction, deformation bands, subgrain formations, and recrystallized grains. The shear indicators, such as asymmetric porphyroclasts, S-C fabrics, and shear bands, suggest consistent top-to-the-NW shear on both the western and eastern flanks of the MCC. Strain measurements using feldspar porphyroclasts show that the strain intensity (Es), Lode's parameter (υ), and Flinn parameter (k) range from 0.46 to 1.03, −0.23 to 0.62, and 0.23 to 1.6, respectively. Kinematic vorticity (W k ) values, estimated by the Polar Mohr diagram and the C′ methods, range from 0.61 to 0.96, with an average of 0.80, for the mylonitic deformation, and from 0.24 to 0.53, with an average of 0.37, for extensional crenulation cleavage (ecc) domains. The kinematic vorticity values, together with the regional structural background, suggest the Yiwulüshan ductile detachment zone experienced simple-shear-dominated general shearing that formed the mylonitic fabric in the early stages of extension. Later in the deformation history, pure-shear-dominated general shearing dominated when ecc developed. Strain measurements and kinematic vorticity estimates indicate that the Yiwulüshan ductile detachment zone is a lengthening-thinning shear zone. It is proposed that simple-shear-dominated general shear developed during crustal extension and that pure-shear-dominated general shear is related to the upward flow of Precambrian basement and Jurassic plutons. ARTICLE HISTORY

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“…In shear zones the increase in the foliation intensity can be related to an increase in strain intensity and also to a better developed crystallographic fabric (Srivastava et al 1995(Srivastava et al , 2000. The analysis of shear zones involves measurement of shear strain, amount and direction of tectonic transport, percentage of volume loss (Srivastava et al1995) and determination of compression direction.…”

Section: Shear Zone Analysismentioning

confidence: 99%

Structural analyses of the crystalline rocks between Dirang and Tawang, West Kameng district, Arunachal Himalaya

Srivastava

et al. 2011

J Geol Soc India

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In Kameng Valley of Arunachal Pradesh, the crystalline rocks of Se La Group of Higher Himalaya are thrust over the Lesser Himalayan rocks of Dirang Formation, Bomdila Group along the Main Central Thrust and exhibit well preserved structures on macro-to microscopic scales. Detailed analysis of structures reveals that the rocks of the area have suffered four phases of deformation D 1 , D 2 , D 3 and D 4 . These structures have been grouped into (i) early structures (ii) structures related to progressive ductile thrusting and (iii) late structures. The early structures which developed before thrusting formed during D 1 and D 2 phases of deformation, synchronous to F 1 and F 2 phases of folding respectively. The structures related to progressive ductile shearing developed during D 3 phase of deformation, when the emplacement of the crystalline rocks took place over the rocks of Dirang Formation along the Main Central Thrust. Different asymmetric structures/kinematic indicators developed during this ductile/brittle-ductile regime suggest top-to -SSW sense of movement of the crystalline rocks of the area. D 4 is attributed to brittle deformation. Based on satellite data two new thrusts, i.e. Tawang and Se La thrusts have been identified parallel to Main Central Thrust, which are suggestive of imbricate thrusting. Strain analysis from the quartz grains of the gneissic rocks reveals constriction type of strain ellipsoid where k value is higher near the MCT, gradually decreases towards the north. Further, the dynamic analysis carried out on the mesoscopic ductile and brittle-ductile shear zones suggest a NNE-SSW horizontal compression corresponding to the direction of northward movement of Indian Plate.

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Strain and possible volume loss in a high-grade ductile shear zone

Cited by 35 publications

References 47 publications

Implications of strain and vorticity of flow analyses to interpret the kinematics of an oblique convergence event (Zagros Mountains, Iran)

Implications of strain and vorticity of flow analyses to interpret the kinematics of an oblique convergence event (Zagros Mountains, Iran)

Formation of Late Jurassic–Early Cretaceous metamorphic core complexes in Northeast China: insight from a structural study of the Yiwulüshan ductile detachment zone

Structural analyses of the crystalline rocks between Dirang and Tawang, West Kameng district, Arunachal Himalaya

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