Abstract The glacier cover of the Hindu Kush Mountains of Afghanistan provides a natural laborato... more Abstract The glacier cover of the Hindu Kush Mountains of Afghanistan provides a natural laboratory to assess the impact of climate change on the cryosphere. However, to date, not much is known about how the cryosphere in these mountainous regions is responding to climate change. Therefore, using an integrated approach including geospatial technology, climate data, a mass balance study, as well as topographic analysis, we present the first systematic study of glacier fluctuations in the Kokcha sub-basin of the Afghanistan Range for the last 25 years (1990 to 2015). The glacier cover and the number of glaciers in the basin have reduced from 576 km2 and 1007 in 1990 to 492 km2 and 998 in 2015 respectively, losing ~84 km2 (~15%) of the total glaciated area. Besides the mass loss of the glaciers ranges from −0.65 m water equivalent per year and −0.02 m water equivalent per year with an average of −0.20 m water equivalent per year as estimated by the geodetic method. The equilibrium line altitude changes since the Late Pleistocene to the present vary from 810 ± 145 m to 1060 ± 145 m with an average of 722 ± 145 m. The increasing trend of temperature and shifting precipitation seasons have resulted in enhanced glacier recession and the formation of numerous glacial lakes in the basin. In addition to the climatic variables and glacier size, the topographic parameters slope, and elevation are observed to be the dominant factors influencing glacier recession and mass changes in the basin.
Abstract Paleoclimatic constraints from mountain ranges separating major climate systems are impo... more Abstract Paleoclimatic constraints from mountain ranges separating major climate systems are important in understanding past climatic changes. Using the present-day glacial geomorphology combined with the GlaRe model, the last glacial maximum (LGM) of seven representative valley glaciers of the Pir Panjal Range (PPR), Kashmir Himalaya was reconstructed. The Range lies at the interface of the tropical and temperate climates in the NW Himalayas. The glacier reconstructions showed that the glaciers in the Range advanced ~10 km down the present-day cirque margins and attained a thickness of more than 200 m during the LGM. Using six different methods, the equilibrium line altitude (ELA) changes in the selected valleys of the PPR were estimated for which the LGM was reconstructed. ELA depressions calculated for the LGM vary from 374 m to 416 m with a mean of 395 m. The weighted average ELA of the Range lies at an altitude of 3922 m a.s.l showing a general increasing trend from SE to NW of the Range. The published chronology of the loess deposits, a proxy for glacial aridity, shows the evidence of significant glacial advances starting around 350 kya in the valley, which is consistent with the evidence of both the pre- and post-LGM advances observed in this study. The presence of extensive glacier features all across the PPR and the presence of a few small heavily debris-covered glaciers in the Range points towards the rapid deglaciation in the area.
Abstract The ∼289 Ma Panjal Traps of NW India (Kashmir) are part of a series of rift-related mafi... more Abstract The ∼289 Ma Panjal Traps of NW India (Kashmir) are part of a series of rift-related mafic suites (Abor, Sikkim etc.) that were erupted onto northern India (present-day coordinates) around the same time as separation of the Cimmerian blocks of Qiangtang and Sibumasu. We report new data from only the second paleomagnetic investigation of this unit. Standard alternating field and thermal demagnetization methods were used to isolate characteristic magnetizations from seven outcrops at three locations within the Kashmir Valley, NW India. Analysis of four sections (14 individual cooling units) from close to Srinagar, that together form a tectonically coherent sequence spanning ∼3 km of stratigraphy, yield a single-component, primary magnetization with a mean direction of Dec: 134.8°, Inc: 55.3° ( α 95 = 8.9°, k = 21.0). An inclination-only mean of 52.5° ( α 95 = 8.9°, k = 47.2) gives a paleolatitude of ∼33°S (±5°). A paleopole of 110.5°E 8.4°S ( A 95 = 10.7) is also calculated. Assuming the magnetization records a portion of the reverse polarity Kiaman Superchron, the new result indicates extrusion of the Panjal Traps basalts at mid-latitudes in the southern hemisphere. By inference this constrains the location of central Gondwana, and informs debates related to Cimmeria’s detachment from Gondwana.
TIn the last few decades Ponseti method has replaced soft tissue releases as the gold standard in... more TIn the last few decades Ponseti method has replaced soft tissue releases as the gold standard in the management of idiopathic clubfoot. However, the recurrence of the deformity is common without post tenotomy bracing. The purpose of this study was to retrospectively see various attributes of the patients associated with poor outcome after use of Ponseti method in idiopathic clubfoot management. Seventy nine consecutive patients with one hundred and twenty three idiopathic clubfeet treated with Ponseti method by single orthopaedic surgeon were followed for a period of two years and recurrence of the deformity was studied in relation to age of patient at presentation (< 3 months or more), sex of the patient, severity of the deformity ( moderate to severe verses (Vs.) very severe), compliance to post tenotomy bracing (compliant Vs. non compliant), educational level of parents (high school or less) and access of parents to internet (Yes or No) and odds ratio for recurrence and level...
Abstract The glacier cover of the Hindu Kush Mountains of Afghanistan provides a natural laborato... more Abstract The glacier cover of the Hindu Kush Mountains of Afghanistan provides a natural laboratory to assess the impact of climate change on the cryosphere. However, to date, not much is known about how the cryosphere in these mountainous regions is responding to climate change. Therefore, using an integrated approach including geospatial technology, climate data, a mass balance study, as well as topographic analysis, we present the first systematic study of glacier fluctuations in the Kokcha sub-basin of the Afghanistan Range for the last 25 years (1990 to 2015). The glacier cover and the number of glaciers in the basin have reduced from 576 km2 and 1007 in 1990 to 492 km2 and 998 in 2015 respectively, losing ~84 km2 (~15%) of the total glaciated area. Besides the mass loss of the glaciers ranges from −0.65 m water equivalent per year and −0.02 m water equivalent per year with an average of −0.20 m water equivalent per year as estimated by the geodetic method. The equilibrium line altitude changes since the Late Pleistocene to the present vary from 810 ± 145 m to 1060 ± 145 m with an average of 722 ± 145 m. The increasing trend of temperature and shifting precipitation seasons have resulted in enhanced glacier recession and the formation of numerous glacial lakes in the basin. In addition to the climatic variables and glacier size, the topographic parameters slope, and elevation are observed to be the dominant factors influencing glacier recession and mass changes in the basin.
Abstract Paleoclimatic constraints from mountain ranges separating major climate systems are impo... more Abstract Paleoclimatic constraints from mountain ranges separating major climate systems are important in understanding past climatic changes. Using the present-day glacial geomorphology combined with the GlaRe model, the last glacial maximum (LGM) of seven representative valley glaciers of the Pir Panjal Range (PPR), Kashmir Himalaya was reconstructed. The Range lies at the interface of the tropical and temperate climates in the NW Himalayas. The glacier reconstructions showed that the glaciers in the Range advanced ~10 km down the present-day cirque margins and attained a thickness of more than 200 m during the LGM. Using six different methods, the equilibrium line altitude (ELA) changes in the selected valleys of the PPR were estimated for which the LGM was reconstructed. ELA depressions calculated for the LGM vary from 374 m to 416 m with a mean of 395 m. The weighted average ELA of the Range lies at an altitude of 3922 m a.s.l showing a general increasing trend from SE to NW of the Range. The published chronology of the loess deposits, a proxy for glacial aridity, shows the evidence of significant glacial advances starting around 350 kya in the valley, which is consistent with the evidence of both the pre- and post-LGM advances observed in this study. The presence of extensive glacier features all across the PPR and the presence of a few small heavily debris-covered glaciers in the Range points towards the rapid deglaciation in the area.
Abstract The ∼289 Ma Panjal Traps of NW India (Kashmir) are part of a series of rift-related mafi... more Abstract The ∼289 Ma Panjal Traps of NW India (Kashmir) are part of a series of rift-related mafic suites (Abor, Sikkim etc.) that were erupted onto northern India (present-day coordinates) around the same time as separation of the Cimmerian blocks of Qiangtang and Sibumasu. We report new data from only the second paleomagnetic investigation of this unit. Standard alternating field and thermal demagnetization methods were used to isolate characteristic magnetizations from seven outcrops at three locations within the Kashmir Valley, NW India. Analysis of four sections (14 individual cooling units) from close to Srinagar, that together form a tectonically coherent sequence spanning ∼3 km of stratigraphy, yield a single-component, primary magnetization with a mean direction of Dec: 134.8°, Inc: 55.3° ( α 95 = 8.9°, k = 21.0). An inclination-only mean of 52.5° ( α 95 = 8.9°, k = 47.2) gives a paleolatitude of ∼33°S (±5°). A paleopole of 110.5°E 8.4°S ( A 95 = 10.7) is also calculated. Assuming the magnetization records a portion of the reverse polarity Kiaman Superchron, the new result indicates extrusion of the Panjal Traps basalts at mid-latitudes in the southern hemisphere. By inference this constrains the location of central Gondwana, and informs debates related to Cimmeria’s detachment from Gondwana.
TIn the last few decades Ponseti method has replaced soft tissue releases as the gold standard in... more TIn the last few decades Ponseti method has replaced soft tissue releases as the gold standard in the management of idiopathic clubfoot. However, the recurrence of the deformity is common without post tenotomy bracing. The purpose of this study was to retrospectively see various attributes of the patients associated with poor outcome after use of Ponseti method in idiopathic clubfoot management. Seventy nine consecutive patients with one hundred and twenty three idiopathic clubfeet treated with Ponseti method by single orthopaedic surgeon were followed for a period of two years and recurrence of the deformity was studied in relation to age of patient at presentation (< 3 months or more), sex of the patient, severity of the deformity ( moderate to severe verses (Vs.) very severe), compliance to post tenotomy bracing (compliant Vs. non compliant), educational level of parents (high school or less) and access of parents to internet (Yes or No) and odds ratio for recurrence and level...
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Papers by Reyaz A Dar