Geoelectrical studies of the Chuya basin sedimentary fill (Gorny Altai)

Abstract

The VES method was used to determine the geoelectric parameters of Cenozoic rocks in the Chuya intermontane basin. It was shown that the polyfacies and polychromous sediments filling the basin are well differentiated by their electrical parameters. A combination of methods used in data acquisition and processing, due to their high resolution capacity at shallow depths, provided information on the structure and physical properties of the Chuya rocks from surface to depths of 250–300 m. Despite a reasonable consistence among these methods to the above depths, the VES method is a more effective tool for detecting shallower layers. Interpretation of the VES data proved the existence of a large outburst channel as new geological evidence for an ice-dammed origin of the Middle Neopleistocene lake. A more detailed layering of the topmost part of the geoelectrical section across the Irbistu–Kokozek interfluve using the VES data revealed a number of fine-grained lenticular structures of the ancient lakes in the Chuya depression, which are hidden beneath a cover of fluvioglacial and lacustrine bouldery pebbles and moraine diamictons.

Dynamic simulation of catastrophic late Pleistocene glacial-lake drainage, Altai Mountains, central Asia

“…Russian borehole and resistivity data from the basins demonstrate thick Neogene, and lower and middle Pleistocene fill in the basins, but indicate little upper Pleistocene fill or Holocene alluviation (Deev et al 2012); rather some Holocene incision occurs along the talweg. Consequently, the original topography was mapped with average resolutions of 50, 75, and 100 m to perform a mesh sensitivity study.…”

“…The enclosing mountain ranges rise to 4000 m in height and sustain icecaps and valley glaciers today. The basins contained large ice-dammed lakes in the middle Pleistocene, which might have emptied catastrophically, but little is known of these lakes (Zol'nikov et al 2010;Deev et al 2012) and so these waterbodies are not considered herein. During the late Pleistocene glacial ice was extensive and, although ice did not extend into the lake basins significantly, ice lobes did block the drainage outlet from the basins to the northwest, in the vicinity of the town of Aktash (Herget 2005).…”

Radiocarbon dating of organic-rich deposits: Difficulties of paleogeographical interpretations in highlands of Russian Altai

“…Next two sections (5 and 6) are located in the northwestern periphery of the Chuya intermountain depression, in the valleys of temporal creeks, which drain the southern slope of the Kurai range. In this part of the Chuya basin, Jurassic, Paleogene, and Neogene organicrich lacustrine and boggy-lacustrine deposits, including interbeds of brown coals, are widely exposed at the surface, and, according to drilling and geophysical studies, are traced under Quaternary deposits (Devyatkin, 1965;Nekhoroshev, 1966;Luzgin and Rusanov, 1992;Buslov et al, 1999;Shokalsky et al, 1999;Selin and Goverdovsky, 2000;Nevedrova et al, 2001;Deev et al, 2012). Sliding and redeposition of Paleogene-Neogene deposits at the foot of the Kurai range in this part of the basin has an areal distribution.…”

The neotectonic structure of intermountain basins of Mountainous Altai according to electromagnetic and geological data

“…Как уже отмечалось, именно метод ВЭЗ дает возможность определить УЭС и толщины как приповерхностных слоев небольшой мощности в 1-2 м, так и более глубоко залегающих отложений -до глубин в среднем до 200-300 м (в зависимости от ве личины максимального разноса питающей линии и геоэлектрических параметров разреза). Очевидно, что далее при полной обработке полевых данных парамет рические измерения позволят уменьшить модельную эквивалентность решения обратных задач, особенно на участках, где отсутствуют скважины, и дадут возмож ность идентифицировать аналогичные отложения в сложных случаях, когда они полностью перекрыты другими породами и находятся на значительных глу бинах [Deev et al, 2012a].…”