Haflong Thrust

2020-08-23T01:54:11Z

2A00:23C6:1A00:5300:503B:2F99:EAD6:1EAA: Shillong capitalised

{{Use dmy dates|date=August 2018}}
{{Use Indian English|date=August 2018}}
The '''Haflong Thrust''' is the most persistent of the [[thrust fault|thrust]]s in the 400 km long [[Belt of Schuppen]] (BoS) in the western part of [[Nagaland]].<ref name=B1>[http://en.banglapedia.org/index.php?title=Haflong_Thrust Haflong Thrust], Banglapedia</ref> The Belt of Schuppen forms the outermost fringe of the [[Orogeny|mobile belt]] of the [[Assam]]–[[Arakan]] basin and forms the most prominent [[Morphotectonics|morphotectonic]] unit of the [[Naga Hills]],<ref name=B1/><ref name=Fr>[http://shodhganga.inflibnet.ac.in/bitstream/10603/48790/12/12%20chapter%202.pdf GEOLOGY AND TECTONIC FRAMEWORK]</ref> where these [[overthrust]]s form a complex pattern (in places, higher ones override the lower ones). The frontal thrust, conventionally known as the Naga thrust, is seen to be composed of four different thrusts. The uppermost thrust is known as the Haflong (Disang) thrust.<ref name=B1/> The Naga-Disang (Haflong) Overthrust area includes besides the Naga Hills proper, a few long ranges of hills fringing the plain of Upper Assam, and a large part of the North Cachar Hills (the Belt of Schuppen).<ref name=B1/> Haflong Fault is the south-westward continuation of the Disang thrust from the Naga Hills to Haflong where the thrust becomes a narrow but complex fracture belt.<ref name=B2>[http://en.banglapedia.org/index.php?title=Haflong_Fault Haflong Fault], Banglapedia</ref> Along with two major thrusts, the Haflong-Naga Thrust and Disang Thrust, studies revealed three minor thrusts (ST-1, ST-2, ST-3) in the BoS.<ref name=Fr/>

The westward continuation of this fracture belt ultimately passes into the [[Dauki fault]]. About 60-km west of Haflong the Dauki fault appears to be a nearly vertical break and the beds on the two sides show no great difference in age. Further west downthrown is southerly and still further west in [[Garo Hills]] the fault heads to the north along which the Shillong plateau has been shifted southwards.<ref name=B2/> In the southwest at the southern fringe of the Shillong plateau Haflong-Naga Thrust and Disang Thrust merge to form a major East-West fault known as the Dauki-Haflong Thrust.<ref name=Fr/>

In Haflong thrusting area, there is much variation in the structure of the south dipping [[monocline]]. In the east, between Haflong and Dauki, the beds north of the fault are mostly horizontal or dip gently down to the south, while those of the south of the fault dip more steeply and in places are nearly vertical. There is extensive shattering in a belt several kilometres wide along the fault.<ref name=B2/> West of Haflong, where the fault has little stratigraphical throw, the [[geosynclinal]] facies of the Eocene approaches within 7 km of the Kopili beds which are part of the calcareous shelf facies of the Eocene, and which immediately overlie the Sylhet Limestone.<ref name=B2/> In the North [[Cachar Hills]] it overrides all the lower thrusts to rest directly on the Foreland Spur. The exposed parts of the thrust sheets nearest the plains are composed principally of rocks of Tipam Series. The exposed parts of the higher thrust sheets are usually made up of chiefly rocks of the Barail Series.<ref name=B1/>

==References==
{{reflist}}

[[Category:Thrust faults]]
[[Category:Seismic faults of Asia]]
[[Category:Geology of India]]
[[Category:Geography of Nagaland]]

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Haflong Thrust