TECTONICS AND GEOLOGICAL STRUCTURE OF THE MAYA-KYLLAKH ZONE (SOUTH VERKHOYANSK REGION) OBTAINED FROM BALANCED CROSS-SECTIONS

Abstract

A technique for balancing cross-sections is used to construct geometrically consistent structural sections through fold-thrust belts. Unlike the predecessor studies, the balanced cross-sections in this study were obtained using the deep seismic sounding and well data and Move Software. Two detailed balanced cross-sections pass through the central part of the South Verkhoyansk region: the 80 km long Yudoma cross-section running along 59°45ʹ N, and the 122 km long Allakh-Yun cross-section within 60°40ʹ – 61°00ʹ N. Both sections are characterized by a thin-skinned structure, "mechanical stratigraphy", emergent leading imbricate fans in the foreland, thick Riphean strata, and eastward dip of the detachment surface. The surface shortening values are ~33 % for the Yudoma cross-section and ~26 % for the Allakh-Yun cross-section, showing an old-to-young-complex decrease from 39 % for the Yudoma cross-section to 19 % for the Allakh-Yun cross-section. On the Yudoma cross-section, the detachment occurs in the Middle Riphean deposits and dips down to 8 km; on the Allah-Yun cross-section, it occurs in the Lower Riphean deposits and dips down to 15 km. The difference in the detachment level may indicate the presence of a ramp between the cross-sections or an inaccurate localization of a ramp between the Central and Kyllakh-Eibeke-Khayata segments. The changes in the geological structure across and along the strike of the orogen are traced; the obtained cross-sections are compared with each other, with other cross-sections across the South and West Verkhoyansk regions, and with the cross-sections through the foreland fold and thrust belts of the Urals, Appalachians, and Cordillera of North America.