The Making of the Himalaya, Karakoram, and Tibetan Plateau

2013 ◽  
Author(s):  
Mike Searle
Keyword(s):  
Tibetan Plateau ◽  
Plate Boundary ◽  
Indian Plate ◽  
North West ◽  
Geological Interpretation ◽  
Mountain Ranges ◽  
The Road ◽  
The North ◽  
On The Road ◽  
The Himalaya

My quest to figure out how the great mountain ranges of Asia, the Himalaya, Karakoram, and Tibetan Plateau were formed has thus far lasted over thirty years from my first glimpse of those wonderful snowy mountains of the Kulu Himalaya in India, peering out of that swaying Indian bus on the road to Manali. It has taken me on a journey from the Hindu Kush and Pamir Ranges along the North-West Frontier of Pakistan with Afghanistan through the Karakoram and along the Himalaya across India, Nepal, Sikkim, and Bhutan and, of course, the great high plateau of Tibet. During the latter decade I have extended these studies eastwards throughout South East Asia and followed the Indian plate boundary all the way east to the Andaman Islands, Sumatra, and Java in Indonesia. There were, of course, numerous geologists who had ventured into the great ranges over the previous hundred years or more and whose findings are scattered throughout the archives of the Survey of India. These were largely descriptive and provided invaluable ground-truth for the surge in models that were proposed to explain the Himalaya and Tibet. When I first started working in the Himalaya there were very few field constraints and only a handful of pioneering geologists had actually made any geological maps. The notable few included Rashid Khan Tahirkheli in Kohistan, D. N. Wadia in parts of the Indian Himalaya, Ardito Desio in the Karakoram, Augusto Gansser in India and Bhutan, Pierre Bordet in Makalu, Michel Colchen, Patrick LeFort, and Arnaud Pêcher in central Nepal. Maps are the starting point for any geological interpretation and mapping should always remain the most important building block for geology. I was extremely lucky that about the time I started working in the Himalaya enormous advances in almost all aspects of geology were happening at a rapid pace. It was the perfect time to start a large project trying to work out all the various geological processes that were in play in forming the great mountain ranges of Asia. Satellite technology suddenly opened up a whole new picture of the Earth from the early Landsat images to the new Google Earth images.

Roof of the World: Tibet, Pamirs

2013 ◽  
Author(s):  
Mike Searle
Keyword(s):  
Tibetan Plateau ◽  
High Elevation ◽  
Tien Shan ◽  
Palm Tree ◽  
The Tibetan Plateau ◽  
Wet Season ◽  
North West ◽  
Mountain Ranges ◽  
The North ◽  
The World

The Tibetan Plateau is by far the largest region of high elevation, averaging just above 5,000 metres above sea level, and the thickest crust, between 70 and 90 kilometres thick, anywhere in the world. This huge plateau region is very flat—lying in the internally drained parts of the Chang Tang in north and central Tibet, but in parts of the externally drained eastern Tibet, three or four mountain ranges larger and higher than the Alps rise above the frozen plateau. Some of the world’s largest and longest mountain ranges border the plateau, the ‘flaming mountains’ of the Tien Shan along the north-west, the Kun Lun along the north, the Longmen Shan in the east, and of course the mighty Himalaya forming the southern border of the plateau. The great trans-Himalayan mountain ranges of the Pamir and Karakoram are geologically part of the Asian plate and western Tibet but, as we have noted before, unlike Tibet, these ranges have incredibly high relief with 7- and 8-kilometre-high mountains and deeply eroded rivers and glacial valleys. The western part of the Tibetan Plateau is the highest, driest, and wildest area of Tibet. Here there is almost no rainfall and rivers that carry run-off from the bordering mountain ranges simply evaporate into saltpans or disappear underground. Rivers draining the Kun Lun flow north into the Takla Makan Desert, forming seasonal marshlands in the wet season and a dusty desert when the rivers run dry. The discovery of fossil tropical leaves, palm tree trunks, and even bones from miniature Miocene horses suggest that the climate may have been wetter in the past, but this is also dependent on the rise of the plateau. Exactly when Tibet rose to its present elevation is a matter of great debate. Nowadays the Indian Ocean monsoon winds sweep moisture-laden air over the Indian sub-continent during the summer months (late June–September). All the moisture is dumped as the summer monsoon, the torrential rains that sweep across India from south-east to north-west.

Colliding Continents

2013 ◽  
Author(s):  
Mike Searle
Keyword(s):  
Indian Plate ◽  
Mountain Range ◽  
Polar Regions ◽  
Geological Evidence ◽  
North West ◽  
Ice Cap ◽  
The North ◽  
West Himalaya ◽  
Tectonically Active ◽  
The Himalaya

The Himalaya is the greatest mountain range on Earth: the highest, longest, youngest, the most tectonically active, and the most spectacular of all. Unimaginable geological forces created these spectacular peaks. Indeed, the crash of the Indian plate into Asia is the biggest known collision in geological history, giving birth to the Himalaya and Karakoram, one of the most remote and savage places on Earth. In this beautifully illustrated book, featuring spectacular color photographs throughout, one of the most experienced field geologists of our time presents a rich account of the geological forces that were involved in creating these monumental ranges. Over three decades, Mike Searle has transformed our understanding of this vast region. To gather his vital geological evidence, he has had to deploy his superb skills as a mountaineer, spending weeks at time in remote and dangerous locations. Searle weaves his own first-hand tales of discovery with an engaging explanation of the processes that formed these impressive peaks. His narrative roughly follows his career, from his early studies in the north west Himalaya of Ladakh, Zanskar and Kashmir, through several expeditions to the Karakoram ranges (including climbs on K2, Masherbrum, and the Trango Towers, and the crossing of Snow Lake, the world's largest ice cap outside polar regions), to his later explorations around Everest, Makalu, Sikkim and in Tibet and South East Asia. The book offers a fascinating first-hand account of a major geologist at work-the arduous labor, the eureka moments, and the days of sheer beauty, such as his trek to Kathmandu, over seven days through magnificent rhododendron forests ablaze in pinks, reds and white and through patches of bamboo jungle with hanging mosses. Filled with satellite images, aerial views, and the author's own photographs of expeditions, Colliding Continents offers a vivid account of the origins and present state of the greatest mountain range on Earth.

Matronianus, Comes Isauriae: an Inscription from an Early Byzantine Basilica at Yanıkhan, Rough Cilicia

1985 ◽  
Vol 35 ◽  
pp. 93-97 ◽  
Author(s):  
Stephen Hill
Keyword(s):  
The South ◽  
Late Professor ◽  
The Road ◽  
Scrub Oak ◽  
The North ◽  
Wild Olive ◽  
On The Road ◽  
Olive Trees ◽  
The Village ◽  
Early Byzantine

The ruins at Yanıkhan form the remains of a Late Roman village in the interior of Rough Cilicia some 8 kilometres inland from the village of Limonlu on the road to Canbazlı (see Fig. 1). The site has not been frequently visited by scholars, and the first certain reference to its existence was made by the late Professor Michael Gough after his visit on 2 September 1959. Yanıkhan is now occupied only by the Yürüks who for years have wintered on the southern slopes of Sandal Dağ. The ancient settlement at Yanıkhan consisted of a village covering several acres. The remains are still extensive, and some, especially the North Basilica, are very well preserved, but there has been considerable disturbance in recent years as stone and rubble have been removed in order to create small arable clearings. The visible remains include many domestic buildings constructed both from polygonal masonry without mortar and from mortar and rubble with coursed smallstone facing. There are several underground cisterns and a range of olive presses. The countryside around the settlement has been terraced for agricultural purposes in antiquity, and is, like the settlement itself, densely covered with scrub oak and wild olive trees. The most impressive remains are those of the two basilical churches which are of little artistic pretension, but considerable architectural interest. The inscription which forms the substance of this article was found on the lintel block of the main west entrance of the South Basilica.

Measured Plans of Urartian Fortresses

1960 ◽  
Vol 10 ◽  
pp. 177-196 ◽  
Author(s):  
C. A. Burney ◽  
G. R. J. Lawson
Keyword(s):  
Preliminary Report ◽  
General Information ◽  
Lake Van ◽  
North West ◽  
The Road ◽  
On The Road

This article comprises descriptive and explanatory notes on a number of plans made during a plane-table survey carried out by the authors in the Van region in the summer of 1957. In addition to the plans and photographs, there are two details, one being an elevation. The form of publication is partly determined by the appearance of sketch-plans of most of these Urartian fortresses in a preliminary article. Apart from correction of certain errors in that article, the general information given therein will not be repeated. For the position of the various fortresses reference should be made to the map published in that preliminary report. To the sites marked thereon should be added two more, Aznavur and Kancıklı, both near Patnos, on the road north-west from Erciş. to Karaköse and thus some way north of Lake Van. Both are of major importance: Aznavur lies one mile north-west of Patnos and Kancıklı some nine miles south-east.

Structure of the North Indian continental margin in the Ladakh–Zanskar Himalayas: implications for the timing of obduction of the Spontang ophiolite, India–Asia collision and deformation events in the Himalaya

1997 ◽  
Vol 134 (3) ◽  
pp. 297-316 ◽  
Author(s):  
MIKE SEARLE ◽  
RICHARD I. CORFIELD ◽  
BEN STEPHENSON ◽  
JOE MCCARRON
Keyword(s):  
Continental Margin ◽  
Suture Zone ◽  
Indian Plate ◽  
Normal Faults ◽  
Initial Contact ◽  
Crustal Shortening ◽  
Northern Margin ◽  
The North ◽  
Late Tertiary ◽  
The Himalaya

The collision of India and Asia can be defined as a process that started with the closing of the Tethyan ocean that, during Mesozoic and early Tertiary times, separated the two continental plates. Following initial contact of Indian and Asian continental crust, the Indian plate continued its northward drift into Asia, a process which continues to this day. In the Ladakh–Zanskar Himalaya the youngest marine sediments, both in the Indus suture zone and along the northern continental margin of India, are lowermost Eocene Nummulitic limestones dated at ∼54 Ma. Along the north Indian shelf margin, southwest-facing folded Palaeocene–Lower Eocene shallow-marine limestones unconformably overlie highly deformed Mesozoic shelf carbonates and allochthonous Upper Cretaceous shales, indicating an initial deformation event during the latest Cretaceous–early Palaeocene, corresponding with the timing of obduction of the Spontang ophiolite onto the Indian margin. It is suggested here that all the ophiolites from Oman, along western Pakistan (Bela, Muslim Bagh, Zhob and Waziristan) to the Spontang and Amlang-la ophiolites in the Himalaya were obducted during the late Cretaceous and earliest Palaeocene, prior to the closing of Tethys.The major phase of crustal shortening followed the India–Asia collision producing spectacular folds and thrusts across the Zanskar range. A new structural profile across the Indian continental margin along the Zanskar River gorge is presented here. Four main units are separated by major detachments including both normal faults (e.g. Zanskar, Karsha Detachments), southwest-directed thrusts reactivated as northeast-directed normal faults (e.g. Zangla Detachment), breakback thrusts (e.g. Photoksar Thrust) and late Tertiary backthrusts (e.g. Zanskar Backthrust). The normal faults place younger rocks onto older and separate two units, both showing compressional tectonics, but have no net crustal extension across them. Rather, they are related to rapid exhumation of the structurally lower, middle and deep crustal metamorphic rocks of the High Himalaya along the footwall of the Zanskar Detachment. The backthrusting affects the northern margin of the Zanskar shelf and the entire Indus suture zone, including the mid-Eocene–Miocene post-collisional fluvial and lacustrine molasse sediments (Indus Group), and therefore must be Pliocene–Pleistocene in age. Minimum amounts of crustal shortening across the Indian continental margin are 150–170 km although extreme ductile folding makes any balancing exercise questionable.

scholarly journals XXXVI. An account of the effects of lightening at South Weald, in Essex

1764 ◽  
Vol 54 ◽  
pp. 198-200
Keyword(s):  
The West ◽  
North West ◽  
The Road ◽  
The North ◽  
Neighbouring Country ◽  
The Church

South Weald is a village in Essex, about eighteen miles distant from London, and two to the north west of Brentwood. In the road from London there is an almost continual ascent for the last four or five miles, which makes a considerable eminence above any parts of the neighbouring country. On the highest part of it stands the church, which has at the west end a tower, and in one corner of this there is a round turret, being a continuation of the stair-case, about four feet wide, eight feet high, and the walls of it one foot thick. In the top of the wall of this turret, which was leaded, are fixed several iron bars, that are bent so as to meet in the middle and support a weather-cock, which was put up about sixteen years ago.

From depth to surface: how deep-earth processes and active tectonics shape the landscape in Pamir and Hindu Kush

2020 ◽  
Author(s):  
Silvia Crosetto ◽  
Sabrina Metzger ◽  
Dirk Scherler ◽  
Onno Oncken
Keyword(s):  
Active Faults ◽  
Indian Plate ◽  
Mountain Range ◽  
Eurasian Plate ◽  
North West ◽  
Continental Scale ◽  
The North ◽  
Lateral Extrusion ◽  
Hindu Kush ◽  
Thrust System

<p>The Pamir and Hindu Kush are located at the western tip of the India-Asia collision zone. Approximately a third of the northward motion of India’s western syntax is mostly accommodated by continental-scale underthrusting of the Indian plate beneath Asia. On its way northwards the arcuate, convex Pamir mountain range acts as a rigid indenter penetrating the weaker Eurasian plate, while lateral extrusion occurs to the west in the Tajik Depression.</p><p>Intense present-day shallow seismicity indicates active deformation along the northern and north-western semi-arid margin of the Pamir, where over the last century several M>6 and three M>7 crustal earthquakes, including a recent M6.4 event in 2016, were recorded. Earthquakes are distributed in the proximity of three main fault systems: the Pamir thrust system to the north, and the Darvaz fault and Vakhsh thrust system to the north-west. The pronounced topographic expression of these lithospheric faults is associated to a deeply incised landscape, which was profoundly shaped by past widespread glaciations. The transient evolution of the landscape following deglaciation is observed in the dynamic river network, characterised by intense fluvial incision and changes in the fluvial connectivity of the drainage system.</p><p>At depth, recent seismic tomography studies suggest delamination, stretching and tearing of the Asian slab beneath SW Pamir, and slab break-off underneath Hindu Kush. Slab break-off episodes are known to result in stress surges in the overlying lithosphere, potentially causing deformation and uplift.</p><p>In this complex system characterised by an important interplay between tectonics, climate and surface processes, we use qualitative and quantitative analyses of the topography and of the drainage systems evolution, inclusive of numerical tools, in order to define what is –and has been- the role played by the main lithospheric active faults of this area. In addition, we aim at identifying how landscape and surface dynamics respond, temporally and spatially, to processes, such as slab tearing/break-off, occurring at depth.</p>

scholarly journals A Microearthquake Study of the Plate Boundary, North Island, New Zealand

2021 ◽  
Author(s):  
◽  
Martin Everardus Reyners
Keyword(s):  
Plate Boundary ◽  
Pacific Plate ◽  
Focal Mechanisms ◽  
Phase Changes ◽  
Indian Plate ◽  
Depth Range ◽  
The North ◽  
The Pacific ◽  
Deep Activity ◽  
Set Up

<p>The seismicity, structure and tectonics of the North Island plate boundary have been studied by means of a microearthquake traverse oriented in the direction of dip of the subducted Pacific plate and stretching from southern Hawke's Bay to northern Taranaki. The geometry of the top of the Pacific plate is inferred from a band of concentrated microearthquake activity which can be identified with the crust of the plate. The Pacific plate appears to have two knee-like bends, one between the east coast and the Ruahine Range, where the top of the plate is about 25 km deep, the other below the volcanic front, where it is about 70 km deep. The shallower bend and subsequent restraightening of the plate can be related to phase changes in the plate, while the deeper bend can be related to volcanism. Composite focal mechanisms indicate that seaward of its shallower bend the Pacific plate is being loaded by the Indian plate, whereas landward of this bend the Pacific plate is sinking under its own weight. Both composite focal mechanisms and the distribution of microseismicity in the Pacific plate suggest the existence of a major discontinuity striking down the dip of the plate and passing beneath the Tongariro volcanic centre. A conspicuous lack of microseismicity in the Indian plate in the eastern North Island revealed in this study can be related to the plates being unlocked in this region. A feature of the seismicity of the Indian plate in the region of the Wanganui Basin is the concentration of activity in the 25-42 km depth range, shallower activity being largely confined to the northeast edge of the basin, near Mt Ruapehu and Waiouru. Composite focal mechanisms suggest the 25-42 km deep activity reflects stresses set up by locking and unlocking of the plates, while the shallower activity reflects local stresses related to volcanic phenomena.</p>

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