Kinematic analysis along 60 km of the shear zone indicates primarily dextral shear, with a minor component of reverse. Mar 27, 2019 the achankovil shear zone aksz is a nwse trending ductile shear zone passing through the southern granulite terrain sgt has remained enigmatic among scientific community for the perspective of shear zone status and extension. Pdf geology of the achankovil shear zone, southern india. The achankovil zone of southern india forms a distinct 8to 10kmwide nwse trending structure that separates the granulitefacies madurai block to the north from the trivandrum block to the. The nwse trending achankovil fault system is a major ductile shear zone within southern peninsular india of precambrian age. Drift ice consists of floes, drift ice consists of floes, 2011 lorca earthquake 1,501 words view diff exact match in snippet view article find links to article.
An integrated approach to resolve the kinematics of the controversial achankovil shear zone aksz has been attempted involving remote sensing data, shaded relief topomaps, ground details of lithology and mesoscopic structures. Pdf coastal zone management plan as per crz notification. Sugan, school of tectonics, department of geology, v. The suruli shear zone and regional scale folding pattern. Pdf achankovil shear zone of tirunelveli regions revisited to examine the charnockitisation processes of this region. African shear along the southwestern edge of the achankovil shear. Jan 01, 2020 the present study area is a part of achankovil shear zone passing through both kerala and tamil nadu states. The achankovil tambraparni shear zone ats is an 8 to 45 km wide tectonic zone trending wnwese to nwse direction and running across the southern end of the sgt. Extension of achankovil shear zone, southern granulite terrain. The shear zone developed along the boundary between a coarsegrained, porphyritic. Shear lineaments analysis of ambasamudramtenkasi transect of achankovil tambraparani shear zone, south india manimaran g.
Geology of the achankovil shear zone, southern india. Each of these blocks share latest neoproterozoic to cambrian ca. Structure and tectonics of on male wistar rats was investigated. Shear lineament analysis of ambasamudramtenkasi transect of achankovil tambraparni shear zone. Hydrogeomorphological observations from thenmala and thenmala. Numerous studies have considered achankovil shear zone as nwse trending precambrian crustal scale structure. Two aspects continue to be debated, whether the aksz is a terrain boundary shear zone, and if so, when the accretion occurred. African shear along the southwestern edge of the achankovil shear belt, south india. The nearest seismic source zone identified is the one located in kkpt shear zone located 7080 km from the study area which produced a m5. Rockbed wear at a flow convergence zone in fifteen mile creek, niagara peninsula, ontario pp.
Jun 11, 2020 the cauvery shear zone system, comprising the moyarbhavani and palghatcauvery shear zones. Oct 26, 2017 the achankovil shear zone aksz in the southern granulite terrain separates the trivandrum block from the madurai block. Detailed structural geological mapping on aspo skb. Shear zones form a continuum of geological structures, ranging from brittle shear zones or faults via brittleductile shear zones or semibrittle shear zones, ductilebrittle to ductile shear zones. It is a nwse oriented shear zone of 120 km length and 1020 km width. Within the central block, the moyar shear zone to the north and the neesw trending bhavani shear to the south delineate the nilgiri block or the nilgiri n granulite massif. Preliminary geochronological data suggests that the deformation in the shear zones. Achankovil shear zone of tirunelveli regions revisited to examine the. Individual shear zones within this belt have maximum osets of about 1 km. Pdf shear lineaments analysis of ambasamudramtenkasi. Jun 11, 2020 the achankovil shear belt of the southern indian peninsular shield is prominent on landsat images. The results also showed that the achankovil shear zone is characterized by a well. The drift ice zone may be further divided into a shear zone, a marginal ice zone and a central pack.
The achankovil shear zone trends nwse with a width of about 15km and extends more than 120 km along its strike. Glimmerite has also been referred to as biotitite, though the use of this term to describe phlogopiterich rocks has been criticized. Structure and chronology across the achankovil terrain. Unusual lithospheric structure and evolutionary pattern of. Two major faults namely thenmala and thenmala south faults are also identified as associated with this shear zone by earlier studies. May 22, 2015 the achankovil zone of southern india forms a distinct isotopic and structural boundary separating the madurai block to the north from the trivandrum block to the south. Gravity signatures, derived crustal structure and tectonics of achankovil shear zone, southern india more. Extension of achankovil shear zone, southern granulite. Implications of shearing on drainage network development in.
Structure and tectonics of the achankovil shear zone, southern. An integrated approach to resolve the kinematics of the controversial achankovil shear zone aksz has been attempted involving remote sensing data, shaded. The trivandrum block, to the south of the achankovil shear zone, is comprised of the kerala khondalite belt, the nagercoil charnockites and the achankovil metasediments. Highgrade metamorphic rocks associated with stype granites are recorded in the central iberian zone, iberian. Rajesh and others published geology of the achankovil shear zone, southern india find, read and cite all the research you need on researchgate. Pdf multiphase shear features of panafrican shearing. Single zircon evaporation ages, together with conventional zircon and garnet chronometry, suggest that all three units underwent upperamphibolite facies metamorphism at.
The cauvery shear zone system, comprising the moyarbhavani and palghatcauvery shear zones. A number of similar lineaments can be identified, on either side of achankovil fault, in the region south of ew trending palghat cauvery shear zone. Jose mathew mahathma gandi university, kottayam, lerala. Pdf neotectonic evidences associated with achankovil. Vallanadu area is a high grade metamorphic terrain of amphibolite to granulite grade forms a part of achankovil shear zone and had experienced dextral and sinistral shears of conjugate fracturing nature was delineated15. The mineralization is associated with pegmatites or veins. Neotectonic evidences associated with achankovil shear zone using. Apr 29, 2010 as the pivot is located near achankovil shear zone which trends wnwese dip towards ssw, the suruli shear zone could be splaying branching out from achankovil shear zone. Implications of shearing on drainage network development. Glimmerite is an igneous rock consisting almost entirely of dark mica biotite or phlogopite. Paleoposition of india and madagascar at 500 ma in the gondwanaland assembly modified after rekha et al.
Rockbed wear at a flow convergence zone in fifteen. Brittle and ductile deformational structures in tectonic zones. A shear zone is a zone of strong deformation with a high strain rate surrounded by rocks with a lower state of finite strain. Citeseerx morphoecotypes of endemic flowering plants. Role of microfabrics and magnetic fabrics in the tectonic. Morphometric and seismic hazard analysis of achankovil shear.
Edinburgh research explorer connecting repositories. Various geomorphic indices and longitudinal profiles of the river systems in the aksz, viz. Morphometric and seismic hazard analysis of achankovil. Syntectonic anatexis and magmatism in a midcrustal. The wnwese trending achankovil shear zone asz in southern india is a major crustal discontinuity of proterozoic age which separates kerala khondalite belt kkb in the south from the charnockite massif in the north.
Aeromagnetic signatures of precambrian shield and suture. South of wdc and edc lies the sgt terrain below latitude 12. Earlier researchers evinced that, achankovil shear zone aksz played a key role in invasion of an african element to the indian subcontinent mathew 2015. Aug 01, 2006 the cauvery shear zone system, comprising the moyarbhavani and palghatcauvery shear zones. Dhanya vijayan centre for earth science studies academia.
The moderately deformed samples from the margins of the shear zone have a homogeneous microstructure composed of mostly olivine and orthopyroxene fig. In a nutshell, the suruli shear zone could be a splay, rotational thrust or reverse fault. Shear lineaments analysis of ambasamudramtenkasi transect of. Followup work across the pcsz has revealed discontinuities in lithologic units, structural geology, metamorphic pt conditions, nd model ages, and rbsr mineral ages drury et al. Morphoecotypes of endemic flowering plants from achankovil shear zone in agasthyamalai biosphere reserve, western ghats, kerala by jose mathew and kv george abstract. Several studies have considered achankovil shear zone as nwse trending precambrian crustal scale structure. Field occurrence of highgrade metamorphic rocks in punnalathupadi a, b, vallikodu kottayam c to g, and muthupezhungal h to 0 within the achankovil shear zone. Unravelling the complexities in highgrade rocks using. The grain size of both minerals is relatively coarse 23mm and the grains do not exhibit a strong shape. These shear zones are now known as 1 the moyarattur shear zone, 2 the bhavani shear zone, 3 the palghat cauvery shear zone pcsz, and 4 the achankovil shear zone. We combine isotopic and trace element geochemistry of major and accessory phases with phase equilibria modelling to provide quantitative constraints on the timing and conditions of peak metamorphism and the nature of the. A new perspective on the significance of the ranotsara shear zone. Observed lithological differences from northern end to southern end of the structure delineated this as a separate zone rajesh and chetty, 2006. Shear zone, 3 the palghat cauvery shear zone pcsz, and 4 the achankovil shear zone.
The application of single zircon evaporation and model nd. A thrust zone possibly exists around the eastern margin of edc drury et al. In the floristic expedition in achankovil shear zone part of southern western ghats, a variant of ariopsis peltata was collected which differs from the typical species mainly by the miniature leaf size, domed male zone, and by two rings of punctured cavities in synandria. We present, for the first time, a detailed fieldbased. Exhumation of a migmatite complex along a transpressive shear zone.
The achankovil shear zone aksz is a nwse trending ductile shear zone passing through the southern granulite terrain sgt has remained enigmatic among scientific community for the perspective of shear zone status and extension. Pdf charnockitisation of achankovil shear zone researchgate. In this context, the occurrence of afrochlorophytum australasian element, particularly this newly described species, in the aksz deserves further investigation. A pdf version of this document can be downloaded from. Pdf shear zones and crustal blocks of southern india vol 3 2016. Inset map shows configuration of india and madagascar as part of east gondwana. It is characterised by a length to width ratio of more than 5. Glimmerite may contain minor rutile and ilmenite, and variants of glimmerite bearing graphite, spinel, ankerite, pyrite, apatite, and the carbonate minerals calcite and. Drift ice consists of floes, drift ice consists of floes, estella atekwana 1,336 words view diff case mismatch in snippet view article find links to article. Pdf drainage development in achankovil shear zone, south. The type of deformation, grade of anorthosite zone.
Ac achankovil shear zone, am ampanihy shear zone, bc bhavanicauvery shear zone, be bereketa shear zone, ej ejeda shear zone, kkpt karur kambampainavutrichur shear zone, ma moyarattur shear zone, pc palghatcauvery shear zone. In south india, the wnwstriking kmlong achankovil shear zone aksz separating the trivandrum block and the madurai block is speculated to continue within southern madagascar in the east gondwanaland. Along southwestern edge and parallel to ats there is an another dextral shear zone known as tenmalaigatana shear zone tgs manimaran and roy chacko, 1996. Structure and tectonics of the achankovil shear zone. Hydrogeomorphological observations from thenmala and. Achankovil shear zone aksz is the madurai block and further south of aksz is the kerala khondalite block, a seat of metasedimentary granulites. International science congress association 1 shear lineaments analysis of ambasamudramtenkasi transect of achankovil tambraparani shear zone, south india manimaran g.
Pdf neotectonic evidences associated with achankovil shear. Sinistrally displaced quartzite exposure for 4 km is observed along achankovil shear zone near tenkasi figurethe present study indicates that the wnwese to nwse trending ats lineament l3 has a sinistral sense of slip, while nnwsse to nwse striking tgs lineament l2 shows a dextral sense of slip, indicating that they belonged to two. The present study identified segmented lineaments in. Request pdf structure and tectonics of the achankovil shear zone, southern india an integrated approach to resolve the kinematics of the. The rats were achankovil shear zone, southern india. Field investigations reveal a major shear zone along the southwestern edge of the achankovil shear belt, the tenmala shear zone. The ranotsara shear zone has been correlated with various ductile shear zones in southern india fig. An excellent correlation of structural trends exists on all scales of observation.
Age and tectonic evolution of neoproterozoic ductile shear. Palghat cauveryshear zone pcsz is the central block meertet al. The madras block lies to the east of salem attur shear and is bounded by the pcsz to the south. The achankovil shear zone aksz is a nwse trending ductile shear zone passing through the southern granulite terrain sgt has. Dec 01, 2016 the achankovil shear zone aksz, a nwse trending strike slip shear zone of late proterozoic age, situated in the southern part of the sgt, is conspicuous in the satellite imageries and aero magnetic data drury and holt, 1980, drury et al. Morphoecotypes of endemic flowering plants from achankovil.
Outreach volume vii 2014 128 5 a multidisciplinary refereed journal multiphase shear features of panafrican shearing events of achankovil shear zone, south india g. The achankovil river drains this structural valley. Magmatic events of late neoproterozoic period have also been reported from aksz rajesh et al. Cordierite gneiss from the achankovil shear zone fig.
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