| 翻訳と辞書 |
| Geology of Bolivia ： ウィキペディア英語版 |
Geology of Bolivia
The geology of Bolivia comprises a variety of different lithologies as well as tectonic and sedimentary environments. On a synoptic scale, geological units coincide with topographical units. The country is divided into a mountainous western area affected by the subduction processes in the Pacific and an eastern lowlands of stable platforms and shields. The Bolivian Andes is divided into three main ranges; these are from west to east: the Cordillera Occidental that makes up the border to Chile and host several active volcanoes and geothermal areas, Cordillera Central (in some contexts also called Cordillera Oriental) once extensively mined for silver and tin and the relatively low Cordillera Oriental that rather than being a range by its own is the eastern continuation of the Central Cordillera as a fold and thrust belt. Between the Occidental and Central Cordillera the approximately 3,750-meter-high Altiplano high plateau extends.〔(The Use of Solar Energy for Improving the Living Conditions in Altiplano/Argentina )〕 This basin hosts several freshwater lakes, including Lake Titicaca as well as salt-covered dry lakes that bring testimony of past climate changes and lake cycles. The eastern lowlands and sub-Andean zone in Santa Cruz, Chuquisaca, and Tarija Departments was once an old Paleozoic sedimentary basin that hosts valuable hydrocarbon reserves. Further east close to the border with Brazil lies the Guaporé Shield, made up of stable Precambrian crystalline rock.
==Andes==
The Andes of Bolivia began to rise about 200 million years ago (mya) during the Jurassic. The western margin of what is now South America had been the place of several other orogenies before the Andes rose. It has been hypothesized that the central Andes gained its great height 26 to 14 mya as result of a compressive failure of the lithosphere beneath Bolivia and neighboring areas.〔(Geology of the Altiplano ), Oregon State University〕 The great heights of the Altiplano, Codillera Occidental and Cordillera Oriental are isostatically compensated by an up to 70 km deep crust. It is not known to which extent climate changes induced by the rise of the Andes caused the extreme aridity of Atacama Desert and adjacent parts of Bolivia or if a preexisting desert climate and associated low erosion rates allowed the mountains to build up to their current heights.〔(Neogene climate change and uplift in the Atacama Desert, Chile )〕〔(Tectonics and Climate of the Southern Central Andes ), ''Annual Review of Earth and Planetary Sciences'', 2007.
Cite: ''"precipitation and erosion may influence the kinematics and locus of tectonic activity in orogens."''〕〔David R. Montgomery, Greg Balco and Sean D. Willett. 2001 (Climate, tectonics, and the morphology of the Andes )
Cite: ''"...like tectonics, nonuniform erosion due to large-scale climate patterns is a first-order control on the topographic evolution of the Andes."''〕 A hypothesis holds that scarce sediment supply to the Atacama Trench caused by arid climate induced high shear stresses in the subduction process that enhanced the Andean mountain building.〔Lamb and Davis. 2003. (Cenozoic climate change as a possible cause for the rise of the Andes ), ''Nature''〕
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Geology of Bolivia」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|