В пределах Онежской структуры Фенноскандинавского (Балтийского) щита Восточно-Европейской платформы обнаружены специфические морфоструктуры, отражающие импульсные сейсмотектонические события. Анализ литературных данных показал, что подобные морфоструктуры выделялись российскими учеными в этих местах уже с XIX века. Изучение их эволюции, кинематики и соотношение морфоструктур с палеопротерозойской геологической структурой региона выяви-ли ряд признаков аккомодации новейших тектонических движений к древней струк-туре. В частности, установлена приуроченность к ней поздне-и послеледниковых разрывов. Обосновывается отнесение большинства из выявленных морфоструктур к дислокациям, сформированным за счет мощных сейсмических воздействий на ряде участков. Подтверждается длительность эволюции палеопротерозойских ин-траконтинентальных морфоструктур и расширяется возможность уточнения оце-нок долговременной сейсмической опасности в области тектонической аккомода-ции Фенноскандинавского щита в пределах флексуры А. А. Полканова. К л ю ч е в ы е с л о в а: Восточно-Европейская платформа; Фенноскандинавский щит; Онежская структура; палеоземлетрясения; тектоническая аккомодация; не-отектоника; палеосейсмодислокации. A. A. Nikonov, A. V. Poleshchuk, D. S. Zykov. ON RECENT FAULTS AND PALEOSEISMIC FRACTURES IN THE PALAEOPROTEROZOIC ONEGA STRUCTURE OF THE FENNOSCANDIAN SHIELDSpecific morphological structures corresponding to impulsive seismotectonic events were identified within the Onega structure of the Fennoscandian (Baltic) shield of the East European platform. Analysis of data from the literature showed that similar morphological structures have been detected by Russian scientists in this area already since the 19 th century. The study of evolution, kinematics, and the correlation of the morphostructures with the region's Palaeoproterozoic geological structure suggest that recent tectonic movements have been accommodated to the ancient structure. In particular, late-and postglacial faults were found to be associated to this structure. We prove that a majority of the identified morphostructures are dislocations caused by strong seismic impacts in a number of areas. The prolonged evolution of the Palaeoproterozoic intracontinental morphostructures is confirmed, and the possibilities for refining the estimates of longterm seismic hazard in the area of tectonic accommodation of the Fennoscandian shield in the central sector of the Polkanov flexure are expanded.
As a result of melting of the last ice sheet in the southeastern edge of the Fennoscandian shield, ridge structures called eskers were formed. One of these eskers is the subject of our study. We have identified both typical non-deformed sedimentary layers and specific intrusive mixture of sand and silt in the esker. The sand and silt were deformed with formation of recumbent and overturned folds, which indicate that they have experienced displacement in a ductile (wet) state. The formation of similar dislocations (diapir folds or glacial intrusion structures) can occur as a result of either dead ice melting or liquefaction during earthquakes.
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