Глубинные магнитотеллурические исследования (МТ-исследования) основаны на изучении естественного переменного электромагнитного поля Земли. С их помощью можно получить информацию об электропроводности земной коры и верхней мантии океанов и континентов. В свою очередь, глубинная электропроводность позволяет делать выводы о флюидном и температурном режимах и реологии земных недр. Глубинные МТ-исследования являются важной частью комплекса методов глубинной геофизики, особенно в тектонически активных регионах.

The Late Paleozoic Tien Shan fold belt was formed in the course of subduction of the crust underlying the past Turkestan ocean under the Kazakh continent and subsequent collision of the latter with the Alai and Tarim massifs. The onset of subduction is evidenced by development of flysch sequences and olistostromes in the accretionary complex of the South Tien Shan: in the terminal Visean–Serpukhovian (~330–325 Ma ago) in the west and in the second half of the Bashkirian Age (~315 Ma ago) in the east of the Kyrgyz Tien Shan [1].1 The onset of collision between the Kazakh continent and Tarim Massif is dated back to the terminal Late Carboniferous based on the initiation of a foredeep along the northern margin of the latter [6]. The mature collision stage began in the mid-Asselian, when the last sea basins disappeared in the Tien Shan and granitoids intruded in its southern segment [1, 9]. The position and age of the volcanic arc that was forming in the course of convergence between the Kazakh continent and the Tarim Massif remain unclear. Recently, this problem acquired particular significance, since the data available for the territory of China imply subduction under the Tarim Massif and an Early Carboniferous age of collision, i.e., substantially older as compared with that assumed for the Kyrgyz region [7].