Building and exhumation of the Western Carpathians: New constraints from sequentially restored, balanced cross sections integrated with low‐temperature thermochronometry

Abstract

Western Carpathian orogeny has been the subject of intense scientific debate due to the occurrence of enigmatic features, leading several authors to provide contrasting geological models. In this paper, a new interpretation for the tectonic evolution of the Western Carpathians is provided based on the following: (i) an analysis of the stratigraphy of the Mesozoic‐Tertiary successions across the thrust belt domains, (ii) a reappraisal of the stratigraphy and sedimentology of the “tectonic mélange” (i.e., the so‐called Pieniny Klippen Belt) marking the suture between the Inner and Outer Carpathians, and (iii) the construction of a series of balanced and restored cross sections, validated by 2‐D forward modeling. Our analysis provides a robust correlation of the stratigraphy from the Outer to the Inner Carpathians, independently of the occurrence of oceanic lithosphere in the area, and allows for the reinterpretation of the tectonic relationships among the Inner Carpathians, the Outer Carpathians, and the Pieniny Klippen Belt and the exhumation mechanisms affecting this orogenic belt. In order to constrain the evolution during the last 20 Ma, our model also integrates previously published and new apatite fission track and apatite (U‐Th‐Sm)/He data. These latter indicate a middle‐late Miocene exhumation of the Pieniny Klippen Belt. In this study, the recent regional uplift of the Pieniny Klippen Belt is described for the first time using a 2‐D kinematic model for the tectonic evolution of the Western Carpathians.

Seismic Moments of Intermediate‐Depth Earthquakes Beneath the Hindu Kush: Active Stretching of a Blob of Sinking Thickened Mantle Lithosphere?

“…Seismic tomography reveals low P and S wave speeds in the uppermost mantle beneath the basin and hence corroborates the inference of lithospheric thinning (Dando et al, ; Mitterbauer et al, ; Ren et al, ). Starting before and continuing during the stretching and thinning of the Pannonian crust, the Carpathian mountain belt developed by crustal shortening and thickening (e.g., Behrmann et al, ; Burchfiel & Nakov, ; Castelluccio et al, ; Faccenna et al, ; Knapp et al, ). Although some argue that subduction of oceanic lithosphere occurred beneath the Carpathians, Knapp et al () inferred that subduction of oceanic lithosphere cannot account for the extent of lithosphere required by the zone of intermediate‐depth earthquakes.…”

New data on the age of the sedimentary infill of the Orava-Nowy Targ Basin – a case study of the Bystry Stream succession (Middle/Upper Miocene, Western Carpathians)

“…The Cen tral Carpathian Paleogene and the nearby Pieniny Klippen Belt be gan to be exhumed and eroded, al though the ter rain re lief could have still been mod er ate (Castelluccio et al, 2016). The ob tained age marks also the time when the clastic sed i men ta tion in ter res trial and fresh wa ter en vi ron ments pre vailed.…”

Author Response to SE-2017-117-RC1 (Manuscript files)

“…One caveat of this approach is that material properties are not exhumed during the simulations to modify the surface heat production value. However, an exponential decrease in heat production with depth has the advantage of honoring observations that heat production diminishes with depth through the crust and that this decline is not monotonic (Chapman, 1986;Ketcham, 1996;Brady et al, 2006). This approach not only allows for the matching of measured surface values of heat production in the Himalaya (e.g., Whipp et al, 2007), but also produces reasonable middle and lower crustal temperatures that would not produce partial melts.…”