Naslov
Slab gap or descending lithosphere slab beneath the Dinarides - comparison of several tomographic models

Autori
Šumanovac, Franjo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
17th TSK / Ustaszewski, Kamil ; Grützner, Christoph ; Navabpour, Payman - Jena : Druckzentrum FSU Jena, 2018, 124-124

Skup
17th Symposium of Tectonics, Structural Geology and Crystalline Geology (TSK Jena 2018)

Mjesto i datum
Jena, Njemačka, 19.03.2018. - 25.03.2018

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Slab gap, Dinarides, Tomographic models

Sažetak
Since the theory of plate tectonics initiated, some considerations about a subduction of the Adriatic microplate beneath the Dinarides have been introduced, although there have been no evidences on the existence of a sinking lithosphere slab in the area. First evidence of the Adriatic subduction in the geological history was presented by Pamić (1998), which took part from the Jurassic to the Paleogene. However, recent geological models were constructed considering the absence of a lithospheric slab or “slab gap” at least beneath the northern Dinarides (Handy et al., 2015). These models were mainly based on some regional and global tomographic models (Piromallo and Morelli, 2003 ; Koulakov et al., 2009) that pointed to a lack of the fast anomaly beneath the north Dinarides and presence of the shallow fast anomaly in the south Dinarides. Teleseismic tomography can efficiently discover lithospheric slabs sinking in the asthenosphere on the basis of fast velocity anomalies. The method is characterized by very good horizontal resolution and poor vertical resolution. Teleseismic events are used and incident rays at the receivers are sub-vertical and steeply inclined, and horizontal velocity changes can be easily detected, while vertical velocity changes can’t. However, a good horizontal resolution depends on the space sampling, which means the study area should be uniformly covered by the receivers. Seismic arrays applied in the Piromallo-Morelli and Koulakov models do not satisfy this requirement, so the space sampling is poor. In the both arrays several stations were used in the north Dinarides and several in the south Dinarides, while the central Dinarides were not covered. The study area was much better sampled by the array applied by Šumanovac et al. (2017), and the seismic stations in the central Dinarides were also used. This model has better resolution due to 39 seismic stations used, contrary to 18 and 12 stations in the previous arrays. Šumanovac et al. (2017) interpreted shallow lithospheric slab beneath the north Dinarides and deep lithospheric slab beneath the south Dinarides on the basis of the Dinaridic fast velocity anomaly. Shallow fast velocity anomaly in the north Dinarides was for the first time discovered by Šumanovac and Dudjak (2016). In the model of Šumanovac et al. (2017) the fast anomaly is attenuated in the area of the north Dinarides and gives an impression about the break in the lithospheric slab between the north and south Dinarides. Synthetic model was constructed with the shallow vertical slab (down to 250 km) in the north Dinarides and the deep vertical slab in the south Dinarides (down to 450 km). Inverse velocity model for the initial synthetic model shows an attenuation and taper of the fast anomaly in the north Dinarides, so apparent discontinuity could be noticed, such as in the inverse model for the observed data. Besides, a close correlation between the inverse models for the synthetic and the observed data can be noticed. Accordingly, this seismic modelling verifies previous interpretation that the shallow Adriatic slab exists beneath the north Dinarides and the deep Adriatic slab beneath the south Dinarides, which is in general uniformly thick, and there is no breakage in the slab.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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