Landforms of the Lower Hushe Valley (Central Karakoram, Pakistan)
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Journal of Maps ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/tjom20 Landforms of the lower Hushe Valley (Central Karakoram, Pakistan) Ane Zabaleta , Irantzu Alvarez , Arantza Aranburu , Eñaut Izagirre , Jesus A. Uriarte , Tomás Morales & Iñaki Antiguedad To cite this article: Ane Zabaleta , Irantzu Alvarez , Arantza Aranburu , Eñaut Izagirre , Jesus A. Uriarte , Tomás Morales & Iñaki Antiguedad (2020) Landforms of the lower Hushe Valley (Central Karakoram, Pakistan), Journal of Maps, 16:2, 724-735, DOI: 10.1080/17445647.2020.1822939 To link to this article: https://doi.org/10.1080/17445647.2020.1822939 © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps View supplementary material Published online: 04 Oct 2020. Submit your article to this journal Article views: 333 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tjom20 JOURNAL OF MAPS 2020, VOL. 16, NO. 2, 724–735 https://doi.org/10.1080/17445647.2020.1822939 Science Landforms of the lower Hushe Valley (Central Karakoram, Pakistan) Ane Zabaleta a, Irantzu Alvarez b, Arantza Aranburu a, Eñaut Izagirre a,c, Jesus A. Uriarte a, Tomás Morales a and Iñaki Antiguedad a aGeology Department, Science and Technology Faculty, Hydro-Environmental Process Research Group, University of the Basque Country (UPV/EHU), Leioa, Spain; bDepartment of Graphic Design and Engineering Projects, Hydro-Environmental Process Research Group, Engineering School of Bilbao, University of the Basque Country (UPV/EHU), Bilbao, Spain; cBasque Centre for Climate Change (BC3), Leioa, Spain ABSTRACT ARTICLE HISTORY This paper presents a new geomorphological map for the lower Hushe Valley (below 3400 m Received 27 April 2020 asl), located to the SE of the Central Karakoram in Baltistan (North Pakistan). Fieldwork and Revised 1 September 2020 remote sensing were combined to improve understanding of the most recent surface Accepted 9 September 2020 landforms to produce a 1:50,000 scale map. Thirteen landform types associated with glacial, fl fi KEYWORDS uvial, gravitational and mass wasting processes were identi ed and mapped. Particular Glacial landforms; fluvial emphasis was made on currently dynamic processes that could pose a threat to the landforms; gravitational population. The distribution of the landforms on the valley (reworked tills, alluvial fans, landforms; mass wasting rockfalls, among others) differs between the eastern and the western hillslopes, and from processes; Hushe valley- north to south, mainly due to bedrock types, location of geological structures and Karakoram; Pakistan distribution of lateral tributaries. This map is the first and necessary step towards a deep assessment on geological risk related to external processes in the area. 1. Introduction and aerial imagery with thorough fieldwork in order to map the most recent surface landforms. The map pre- The Central Karakoram is one of the most rapidly ris- sented here provides a basis for future geochronological ing areas on Earth (rates of uplift are estimated to be − assessment that would complement those carried out in between 2 and 6 mm y 1), with complex topography neighbouring valleys (Hewitt, 1999; Owen, 1989; Seong and extreme relief, providing one of the best natural et al., 2009) and for a refined reconstruction of past pro- laboratories to study complex landscape evolution cesses that are being conducted using sedimentological (Leland et al., 1998; Rex et al., 1988). Feedback mech- analysis. As far as we know, this is the first detailed geo- anisms between climate, surface processes and tec- morphological map for the lower Hushe Valley includ- tonics have been proposed to explain landforms in ing the main landforms. the Central Karakoram (Ahmed & Rogers, 2014). However, according to some studies, surface processes are the dominant events that govern landscape evol- 2. Study area ution during interglacial times (Shroder et al., 2011). Debuttressing of slopes due to glacier retreat may The Hushe River basin is located to the SE of the Cen- have prepared the slopes for failure (Ballantyne, tral Karakoram National Park (CKNP) in Pakistan 2002; Hewitt et al., 2011). As a result, ubiquitous (Figure 1(a)), south of the Baltoro glacier and high mass movements have transported and transport mountains such as Masherbrum (7821 m). It is a material from steep slopes to valley bottoms while gla- north–southorientedvalleywithanareaof1230km2 ciofluvial meltwater redistributes sediment down the and elevations between 2441 and 7821 m (Figure 1 valley (Seong et al., 2009). (b)). The area exhibits a complex topography and a The present study is part of a development complicated interaction among erosion, transport and cooperation project to increase the resilience of the sedimentation processes involving glaciers, slopes and Hushe Valley inhabitants (Central Karakoram) to the rivers, which produce a wide variety of landforms. hydro-geomorphological processes that pose a threat. The thickening of the crust, the rise of the continent With this in mind, our research focused on identifying and its erosion have produced in the area, beyond an and mapping the landforms of the lower Hushe Valley extreme topography, abundant exposures of the deep (Figure 1). The complex geological setting makes it crust of the Asian plate (Searle et al., 1989). Geologi- essential to combine the preliminary analysis of satellite cally, the valley is located between the Karakoram CONTACT Ane Zabaleta [email protected] Geology Department, Science and Technology Faculty, Hydro-Environmental Processes Research Group, University of the Basque Country UPV/EHU, Leioa, 48940, Basque Country, Spain © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrest- ricted use, distribution, and reproduction in any medium, provided the original work is properly cited. JOURNAL OF MAPS 725 Figure 1. (a) Location of Hushe valley. (b) Elevation map of the Hushe River basin, showing the river and its main tributaries and sub-basins, villages, glaciers and highest peaks. (c) Longitudinal profile of the Hushe River (A-A’ in b) with the location of the villages. (d) Simplified geological map of the basin with the main geological structures and lithological complexes (modified from Palin et al., 2012). Batholith to the north-east and the Shyok Suture Zone of geomorphological processes in the region (Hewitt, (SSZ) or the Main Karakoram Thrust (MKT) to the 2005): the lower zone, below 3000 m asl, dominated south-west (Palin et al., 2012). The Hushe River course by fluvial processes comprises deep gorges and valley is mainly located at the contact between materials of bottoms where most of the areas are covered by gla- different nature: in the east mainly plutonic materials ciofluvial and gravitational hillside sediments (Seong integrated within the Karakoram Batholith (Cretac- et al., 2009); the middle zone, between 3000 and eous-Miocene rocks) and in the west rocks from the 6000 m asl, dominated by glacial surfaces and/or sedi- Karakoram Metamorphic Complex, (Paleozoic-Juras- ments and mountain ridges; and, the upper zone sic rocks) that mainly consist of gneisses, metapelites extending above 6000 m asl, covered by perennial and marbles (Rolland et al., 2006)(Figure 1(d)), ice and snow, and comprising the highest peaks and which increase in metamorphic degree towards the ridges in the region. The Main Map produced focuses north. on the lower Hushe Valley (below 3400 m asl), an area The effect of the high elevation together with the where the human population, civil infrastructure and precipitation’s altitudinal variation results in zoning main cultivation areas are located. A significant part 726 A. ZABALETA ET AL. of the external geological processes concentrates in gradient-shaded models were constructed using a this area, although their origin is mostly triggered in mosaic of Radiometric Terrain-Corrected (RTC) the upper-middle zone. ALOS PALSAR Global Radar Imagery (12.5 m resol- The Hushe River, with a length of 42.4 km, runs ution) from the VERTEX (https://vertex.daac.asf. from east to west at the head of the valley, where it alaska.edu/) repository, primarily to provide topo- receives the meltwaters from the Chogolisa-Charakusa graphic context. Additionally, the composite mosaic and Ghondogoro glaciers (Figure 1(b)). Then, after of the 8 m resolution HMA (High Mountain Asia) receiving the tributaries of Masherbrum and Lokpar/ DEM (Digital Elevation Model) derived from high- Aling glaciers, it runs north to south towards its resolution optical imagery (Shean, 2017) has been confluence with the Saltoro River, near Machulu, used to improve the mapping quality and landform and the Shyok River (Indus basin) near Saling (Main identification. Contemporary glaciers were identified Map), both coming from the east side. At this point using the most current version 6.0 of the Randolph where the three rivers converge, an extensive funnel- Glacier Inventory (RGI Consortium, 2017), which shaped deposition area is formed, accumulating a was manually corrected to update the outlines to the large part of the materials eroded and transported by 2019 extensions. the Hushe River (mainly silt,