Thermochronology and Exhumation History of the Northeastern Fennoscandian Shield Since 1.9 Ga: Evidence From 40 Ar/ 39 Ar and Apatite Fission Track Data From the Kola Peninsula

• Published in: Tectonics
• Main Authors: Veselovskiy, Roman V., Thomson, Stuart N., Arzamastsev, Andrey A., Botsyun, Svetlana, Travin, Aleksey V., Yudin, Denis S., Samsonov, Alexander V., Stepanova, Alexandra V.
• Other Authors: Univ Arizona, Dept Geosci
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER GEOPHYSICAL UNION 2019
• Subjects: Geochemistry and Petrology; Geophysics; Fennoscandia; Kola Peninsula; Ar; Ar dating; apatite fission track; thermal history; tectonics; Fennoscandian; kola peninsula; Lapland
• Online Access: http://hdl.handle.net/10150/634481; https://doi.org/10.1029/2018tc005250

Results from thermochronological studies have multiple applications to various problems in tectonics and landform evolution. However, up to now a lack of thermochronological data from the northeastern Fennoscandian Shield has complicated the interpretation of tectonothermal evolution of the region. Here, we use both new and previously published multimineral Ar-40/Ar-39 data (amphibole, mica, and feldspar) on the various Precambrian magmatic and metamorphic complexes to reconstruct the thermal history of NE Fennoscandia within the Kola Peninsula area in the interval 1900-360 Ma. Using the apatite fission track method as well as a numerical model of the heating-cooling process of northeastern Fennoscandia's upper crust, we have reconstructed its thermal evolution for the interval 360-0 Ma. According to our model, since Lapland-Kola orogenesis (1930-1905 Ma) northeastern Fennoscandia experienced a quasi-monotonous cooling with the average rate of 0.15 degrees C/Myr, which is equal to an exhumation rate of 1-2 m/Myr. New apatite fission track data and time-temperature modeling reveal a hidden endogenous thermal event in the NE Fennoscandia that took place between 360 and 300 Ma. This we attribute to an elevated geothermal gradient due to Baltica's drift over the African large low shear-wave velocity province in the lowest mantle and/or thermal blanketing by insulating Devonian-Carboniferous sedimentary/volcanic cover. Our model is further supported by evidence of Late Devonian-Carboniferous rifting in the East and South-Western Barents Basin, as well as various 360-300 Ma magmatic events within SW Fennoscandia and the Baltic countries. Russian Science Foundation [16-17-10260]; Russian Government [220, 14.Z50.31.0017]; grant of President of Russian Federation [MD1116.2018.5]; State scientific program of IPGG; IPE RAS; state assignment project of Sobolev Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences [0330-2016-0013] 6 month embargo; published online: 13 July 2019 This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [e-mail].