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The contact zone between the Alcapa and Tisza-Dacia mega-tectonic units of northern Romania in the light of new paleomagnetic data

Marton, Emoe and Tischler, Matthias and Csontos, Laszlo and Fügenschuh, Bernhard and Schmid, Stefan M.. (2007) The contact zone between the Alcapa and Tisza-Dacia mega-tectonic units of northern Romania in the light of new paleomagnetic data. Swiss Journal of Geosciences, 100 (1). pp. 109-124.

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Abstract

Paleomagnetic analyses were carried out on samples from 19 localities within two different mega-tectonic units in Northern Romania: Tisza-Dacia (11 localities) and ALCAPA (8 localities). The samples cover a range of different lithologies: (1) Late Cretaceous red-coloured marl to marly limestone, (2) Eo- Oligocene flysch sediments, and (3) mid-Miocene (Langhian) tuffite (Dej tuff and related sediments). The Late Cretaceous and mid-Miocene specimens carry secondary paleomagnetic signals exhibiting a counter clockwise deflection of the paleo-declinations by some 30°, while the Eo-Oligocene localities indicate an overall clockwise deflected (between some 45° and <90°) paleodeclination with respect to present-day north. Clockwise rotation postdates the age of sedimentation (Lower Oligocene), as well as (at least partially) thrusting of the Pienides onto the Tisza-Dacia mega-tectonic unit, which occurred between 20.5 and 18.5 Ma. Clockwise rotation predates post-12 Ma counter clockwise rotations inferred for the mid-Miocene localities. Surprisingly, the clockwise rotations of the first rotational stage not only affected the (par-) autochthonous sedimentary cover of the Tisza-Dacia megatectonic unit, but also the allochthonous flysch nappes of the Pienides, i.e. the eastern tip of the ALCAPA mega-tectonic unit. Well-documented opposed rotation of the remainder of ALCAPA necessitates a detachment of this eastern tip of ALCAPA after 18.5 Ma. The most likely location for this detachment zone is along the margins of the Transcarpathian depression. During a second (post-12 Ma) stage, counter clockwise rotations of up to 30° affected the entire working area. Regarding timing and magnitude, these second stage rotations are similar to rotations documented for the East Slovak basin, but different from those reported from the South Apuseni Mountains and the Central and Inner West Carpathians located west of the East Slovak basin.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Geologie-Paläontologie > Tektonik (nn)
UniBasel Contributors:Schmid, Stefan M.
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:Birkhäuser
ISSN:1661-8726
Note:Note: Zugleich als Sonderdruck erschienen -- Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:27 Sep 2017 14:42
Deposited On:22 Mar 2012 14:01

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