Regional correlation of the Earth Gravitational Model 08 with morphogenetic patterns of the Nepal Himalaya

Jan Kalvoda,Jan Kostelecký,Jaroslav Klokočník

doi:10.14712/23361980.2015.48

Abstract

Results of the correlation of regional features of the Earth Gravitational Model 2008 (EGM 08) with morphogenetic and orographical patterns of the Nepal Himalaya are presented. Strong coincidences between large-scale morphogenetic styles of the Nepal Himalaya and the extension of regions with very high positive values of the radial second derivative of the disturbing gravitational potential Tzz and the most likely in combination with conspicuous areas of high negative values of Tzz in their close neighbourhood, have been identified. These variable values of Tzz display significant gravitational signatures of extensive differences and changes in mass density and/or rock massif and regolith distributions which occurred during very dynamic landform evolution of the Nepal Himalaya in the late Cenozoic. <b>Regionální korelace modelu gravitačního pole Země 2008 s morfogenetickými styly Nepálského Himálaje</b> V práci jsou předloženy výsledky korelace regionálních rysů modelu gravitačního pole Země 2008 (EGM 08) s morfogenetickými styly Nepálského Himálaje. Byly zjištěny podstatné shody mezi oblastmi s vysokými kladnými hodnotami radiální složky druhé derivace poruchového gravitačního potenciálu Tzz, které jsou často doprovázeny blízkými areály výrazně záporných hodnot Tzz, a specifickými morfogenetickými styly pohoří. Tyto variabilní hodnoty Tzz představují významný gravitační záznam značných rozdílů a změn hustoty hmoty resp. rozčlenění horninových masivů a regolithu, které jsou důsledkem velmi dynamického vývoje povrchových tvarů Nepálského Himálaje v mladším kenozoiku.

Highlights

Landforms in the Himalaya and neighbouring regions provide evidence for the nature of very dynamic landscape evolution, including extremely high rates of denudation, sediment transfer and deposition
We focused on the regional distribution of the free-air gravity anomalies (∆g) and, especially, on the radial second derivative of the disturbing gravitational potential (Tzz) computed from Earth Gravitational Model 2008 (EGM 08)
We focused on the radial second derivative of the disturbing gravitational potential Tzz that show more details than the gravity anomaly itself

Summary

Introduction

Landforms in the Himalaya and neighbouring regions provide evidence for the nature of very dynamic landscape evolution, including extremely high rates of denudation, sediment transfer and deposition. Studies of the geological structure and of the landforms of Himalaya with distinctive features of active lithospheric plate tectonics produce important facts about the extreme intensity of geodynamic processes which, especially in the Quaternary, remodelled this mountain range and neighbouring areas to the present-day shape. We focused on the regional distribution of the free-air gravity anomalies (∆g) and, especially, on the radial second derivative of the disturbing gravitational potential (Tzz) computed from EGM 08 Extension of these parameters is compared with large-scale morphostructural landforms of the Nepal Himalaya. Regional coincidences between selected morphogenetic patterns of the Nepal Himalaya and the extension of ∆g and Tzz have been identified These recorded gravitational field signatures give strong evidence that landform evolution during the very dynamic collision orogeny of the Himalaya and under the influence of variable climatemorphogenetic processes in the late Cenozoic is characterized by significant changes in rock mass density and distribution. Recent evolution of landforms is accompanied by continuing rapid changes in rock massif volume and large-scale relief patterns of the Himalaya and surrounding areas

Earth Gravitational Model 2008

Functions of the gravitational potential of EGM 08

Results

Conclusions