Fault tectonics, neotectonic stresses, and hidden uranium mineralization in the area adjacent to the Strel’tsovka Caldera

Abstract

The scheme of recent fault tectonics and neotectonic stresses of the area adjacent to the Strel'tsovka Caldera in the southeastern Transbaikal region has been compiled for the first time on the basis of structural and geomorphic study. The faults were ranked by criteria of slip direction stability along separate segments and their expression in topography. Neotectonic stresses of corresponding ranks were ascertained as well. The heterogeneity of neotectonic stress field is related to the mosaic development of compression, extension, and the three axial stress state. Comparison of morphogenetic features of recent and older faults shows the different character of the deformation mechanism and orientation of tectonic displacements. It has been established that the Strel'tsovka Caldera and its northwestern segment, in particular, developed as an echeloned system of pull apart grabens, but the caldera itself is situated in a recent rise, whereas the north western segment is located in a neotectonic depression corresponding to the Dry Urulyungui Basin filled with volcanic and sedimentary rocks. Such a structure markedly expands the outlook for discovery of hidden ura nium mineralization in the studied area. The elaborated scheme of neotectonic faults and stresses reflects the postore geodynamic setting and completes the reconstruction of geodynamic conditions pertaining to the periods of preore preparation and ore forming tectonomagmatic reactivation.

Some methodological aspects of tectonic stress reconstruction based on geological indicators

“…К таким работам относится изучение тектонических напряжений угольных месторождений Донбасса [Korchemagin, Ryaboshtan, 1987], урановых месторождений Забайкалья [Petrov et al, 2010], золо торудных месторождений Верхоянья [Zadorozhny, 2002], месторождений платины в Корякии [Vasiliev et al, 1999], алмазоносных трубок Якутии , месторождений пьезосырья на Приполярном Урале [Sim, 2000; Sim et al, 2005, рудных объектов ТяньШаня [Fatkhulaev, Umurzakov, 2009]. В большин стве работ, посвященных тектонофизическому изуче нию мест локализации полезных ископаемых, показа на доминирующая роль разломов в формировании руд ных месторождений [Sim et al, 1987; Gladkov et al, 2008.…”

Prospects of Geoinformatics in Analyzing Spatial Heterogeneities of Microstructural Properties of a Tectonic Fault

“…The preliminary interpretation of the position of stress axes for the sample 61-5 is ambiguous. Figure 13B shows the interpretation of the modern stress-strain field, identified by conducting an analysis of lineaments [75,101,102] in the area of the Sarma River. The orientation of the axes of modern stress field does not coincide with the orientation of the main axes of the stress fields identified in single samples.…”

Results of the tectonic stress study of the Northern Eurasia regions

“…формируются в неотектонический этап в сдвиговом поле напряжений с осями сжатия, ориентировка которых изменяется от субмеридиональной до СВ [Petrov et al, 2010] [Petrov et al, 2010]. Общей характеристикой неотектонических напряжений района исследований является геодинамическая обстановка сжатия и трехосное напряженное состояние.…”