Evidence for pleistocene low-angle normal faulting in the Annapurna-Dhaulagiri region, Nepal

Jeni A. McDermott, Kip Hodges, Kelin Whipple, Matthijs Van Soest, Jose M. Hurtado

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

North-south-directed extension on the South Tibetan Fault System (STFS) played an important role in Himalayan tectonics of the Miocene Period, and it is generally assumed that orogen-perpendicular extension ceased in this orogenic system before the Pliocene. However, previous work in the Annapurna and Dhaulagiri Himalaya of central Nepal revealed evidence for local Pleistocene reactivation of the basal STFS structure in this area (the Annapurna Detachment). New structural mapping and (U-Th)/He apatite and zircon thermochronology in this region further document the significance of Pleistocene N-S extension in this sector of the Himalaya. Patterns of (U-Th)/He accessory-mineral ages are not disrupted across the reactivated segment of the STFS basal detachment, indicating that Pleistocene offset was limited. In contrast, the trace of a N-dipping, low-angle detachment in the hanging wall of the reactivated Annapurna Detachment—formerly linked to the STFS, but here named the Dhaulagiri Detachment—coincides with an abrupt break in the cooling-age pattern in two different drainages ∼20 km apart, juxtaposing Miocene hanging-wall dates against Pleistocene footwall dates. Our observations, combined with previous fission-track data from the region, provide direct evidence for significant N-S extension in the central Himalaya as recently as the Pleistocene.

Original languageEnglish (US)
Pages (from-to)133-151
Number of pages19
JournalJournal of Geology
Volume123
Issue number2
DOIs
StatePublished - Mar 1 2015

Fingerprint

faulting
Pleistocene
hanging wall
Miocene
thermochronology
accessory mineral
footwall
reactivation
apatite
Pliocene
zircon
drainage
cooling
tectonics

ASJC Scopus subject areas

  • Geology

Cite this

Evidence for pleistocene low-angle normal faulting in the Annapurna-Dhaulagiri region, Nepal. / McDermott, Jeni A.; Hodges, Kip; Whipple, Kelin; Van Soest, Matthijs; Hurtado, Jose M.

In: Journal of Geology, Vol. 123, No. 2, 01.03.2015, p. 133-151.

Research output: Contribution to journalArticle

McDermott, Jeni A. ; Hodges, Kip ; Whipple, Kelin ; Van Soest, Matthijs ; Hurtado, Jose M. / Evidence for pleistocene low-angle normal faulting in the Annapurna-Dhaulagiri region, Nepal. In: Journal of Geology. 2015 ; Vol. 123, No. 2. pp. 133-151.
@article{7a19fd9e2771425594aaabbb3331332b,
title = "Evidence for pleistocene low-angle normal faulting in the Annapurna-Dhaulagiri region, Nepal",
abstract = "North-south-directed extension on the South Tibetan Fault System (STFS) played an important role in Himalayan tectonics of the Miocene Period, and it is generally assumed that orogen-perpendicular extension ceased in this orogenic system before the Pliocene. However, previous work in the Annapurna and Dhaulagiri Himalaya of central Nepal revealed evidence for local Pleistocene reactivation of the basal STFS structure in this area (the Annapurna Detachment). New structural mapping and (U-Th)/He apatite and zircon thermochronology in this region further document the significance of Pleistocene N-S extension in this sector of the Himalaya. Patterns of (U-Th)/He accessory-mineral ages are not disrupted across the reactivated segment of the STFS basal detachment, indicating that Pleistocene offset was limited. In contrast, the trace of a N-dipping, low-angle detachment in the hanging wall of the reactivated Annapurna Detachment—formerly linked to the STFS, but here named the Dhaulagiri Detachment—coincides with an abrupt break in the cooling-age pattern in two different drainages ∼20 km apart, juxtaposing Miocene hanging-wall dates against Pleistocene footwall dates. Our observations, combined with previous fission-track data from the region, provide direct evidence for significant N-S extension in the central Himalaya as recently as the Pleistocene.",
author = "McDermott, {Jeni A.} and Kip Hodges and Kelin Whipple and {Van Soest}, Matthijs and Hurtado, {Jose M.}",
year = "2015",
month = "3",
day = "1",
doi = "10.1086/681219",
language = "English (US)",
volume = "123",
pages = "133--151",
journal = "Journal of Geology",
issn = "0022-1376",
publisher = "University of Chicago",
number = "2",

}

TY - JOUR

T1 - Evidence for pleistocene low-angle normal faulting in the Annapurna-Dhaulagiri region, Nepal

AU - McDermott, Jeni A.

AU - Hodges, Kip

AU - Whipple, Kelin

AU - Van Soest, Matthijs

AU - Hurtado, Jose M.

PY - 2015/3/1

Y1 - 2015/3/1

N2 - North-south-directed extension on the South Tibetan Fault System (STFS) played an important role in Himalayan tectonics of the Miocene Period, and it is generally assumed that orogen-perpendicular extension ceased in this orogenic system before the Pliocene. However, previous work in the Annapurna and Dhaulagiri Himalaya of central Nepal revealed evidence for local Pleistocene reactivation of the basal STFS structure in this area (the Annapurna Detachment). New structural mapping and (U-Th)/He apatite and zircon thermochronology in this region further document the significance of Pleistocene N-S extension in this sector of the Himalaya. Patterns of (U-Th)/He accessory-mineral ages are not disrupted across the reactivated segment of the STFS basal detachment, indicating that Pleistocene offset was limited. In contrast, the trace of a N-dipping, low-angle detachment in the hanging wall of the reactivated Annapurna Detachment—formerly linked to the STFS, but here named the Dhaulagiri Detachment—coincides with an abrupt break in the cooling-age pattern in two different drainages ∼20 km apart, juxtaposing Miocene hanging-wall dates against Pleistocene footwall dates. Our observations, combined with previous fission-track data from the region, provide direct evidence for significant N-S extension in the central Himalaya as recently as the Pleistocene.

AB - North-south-directed extension on the South Tibetan Fault System (STFS) played an important role in Himalayan tectonics of the Miocene Period, and it is generally assumed that orogen-perpendicular extension ceased in this orogenic system before the Pliocene. However, previous work in the Annapurna and Dhaulagiri Himalaya of central Nepal revealed evidence for local Pleistocene reactivation of the basal STFS structure in this area (the Annapurna Detachment). New structural mapping and (U-Th)/He apatite and zircon thermochronology in this region further document the significance of Pleistocene N-S extension in this sector of the Himalaya. Patterns of (U-Th)/He accessory-mineral ages are not disrupted across the reactivated segment of the STFS basal detachment, indicating that Pleistocene offset was limited. In contrast, the trace of a N-dipping, low-angle detachment in the hanging wall of the reactivated Annapurna Detachment—formerly linked to the STFS, but here named the Dhaulagiri Detachment—coincides with an abrupt break in the cooling-age pattern in two different drainages ∼20 km apart, juxtaposing Miocene hanging-wall dates against Pleistocene footwall dates. Our observations, combined with previous fission-track data from the region, provide direct evidence for significant N-S extension in the central Himalaya as recently as the Pleistocene.

UR - http://www.scopus.com/inward/record.url?scp=84930064455&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84930064455&partnerID=8YFLogxK

U2 - 10.1086/681219

DO - 10.1086/681219

M3 - Article

AN - SCOPUS:84930064455

VL - 123

SP - 133

EP - 151

JO - Journal of Geology

JF - Journal of Geology

SN - 0022-1376

IS - 2

ER -