This paper presents an integrated measurement technique based on DC methods (vertical electrical sounding, electrical resistivity tomography) which was used to identify faults and determine their geoelectric parameters in the western part of the Chuya basin. New information on the structure of the Chagan River valley located in the zone of the disastrous 27 September 2003 Chuya earthquake has been obtained from the results of these methods. Geoelectric cross-sections of the sedimentary sequence and the upper part of the basement were obtained from VES data, showing the block structure of the study area. Electrical resistivity tomography sections confirm the presence of a major fault between basement blocks of different heights and indicate the presence of faults bounding the valley on its right side and in the southwestern part. 相似文献
The conventional narrative regarding the American reception of George Perkins Marsh, author of Man and Nature (1864), is that his work and ideas were “lost,”“forgotten,” or “neglected” until Lewis Mumford “rediscovered” him and introduced him to geographers at the University of California‐Berkeley through The Brown Decades (Mumford [1931] 1955) and until Carl Sauer made him known to the profession at large beginning in 1938. This article upends the conventional narrative by looking at earlier references to Marsh's later versions of Man and Nature, which were published as The Earth as Modified by Human Action from 1874 to 1907. Analysis reveals that a number of geographers and historians cited these editions between 1875 and the early 1950s. Examining the legend of loss and rediscovery suggests the value of methods utilized in reception studies for research on the history of geography. 相似文献
Results of lithostratigraphic and mineral magnetic analysis of two surficial sediment cores (21 cm and 45 cm in length) collected from the Southern basin of Lake Baikal at a water depth of 1390 m, are presented. The sediments have been measured for a wide range of mineral magnetic parameters in order to assess their value in the identification of turbidite layers. Particle size and geochemical data are also presented and these explain some of the down core variations in magnetic mineralogy. It is suggested that changes in the particle size frequency distributions down core may be related to fossil diatom shells. One of the cores has been dated using 210Pb. The sediment cores were cross-correlated using low frequency magnetic susceptibility (f) and these cores can also be correlated with a nearby core collected earlier in 1992. Changes in the magnetic parameters of lf, IRMs and HIRM210 suggest that there are significant changes in the concentration of ferrimagnetic minerals in the sediment cores, indicating changing sediment sources and/or increasing concentrations of spheroidal carbonaceous particles and the dissolution of minerals through reduction below the oxidised layer within the sediment core. 相似文献