Magnetovariational studies of Lake Ladoga crustal conductivity anomaly: from discovery in 70 th to understanding of its spatial behaviour and deep structure on modern observationsстатья
Дата последнего поиска статьи во внешних источниках: 16 января 2019 г.
Аннотация:The paper addresses the approaches and summarises the results of deep electromagnetic soundings of the Southeastern Fennoscandia in the area of the Lake Ladoga crustal conductivity anomaly, which marks AR-PR border at this part of the Shield. The investigations has been started by pioneering epoch of the discovery of the anomaly with a help of just invented magnetovariational sounding/profiling method, and are continuing today, already on the base of modern technologies of data acquisition and analyses, with the goal to provide more reliable and adequate information of the regional geoelectric structure to constrain recent geological and evolutionary models.
We focus on the results of magnetovariational studies: prospecting and long-period synchronous soundings of 2013-2015 years along Vyborg-Suoyarvi profile crossing the anomaly in strike, and long-period observations of 2016 year at the NE and SE of the Ladoga lake. Methodological aspects of new field experiment as well as noise-suppressing data processing, invariant analyses and interpretation procedures are discussed. The spatial behaviour of the crustal conductors as well as deep architecture of the anomalously conductive crustal area are analysed on the results of 2D inversion of tippers at Vyborg-Suoyarvi line and quasi-3D thin-sheet inversion of regional induction vector ensemble, integrating extended data set over Ladoga lake area and similar Finnish data at the adjacent territory. The resolution of the Lake Ladoga anomaly cross-section as well as its tracing to SE of the area, supported by elaborated regional prognostic 3D geoelectric model, have permitted to interpret the MV sounding results in the geotectonic terms.
