Impact of mechanical stratigraphy on deformation style in the central External Dinarides: a 2D forward kinematic modelling study

Scientific paper - Abstract

• Title (croatian): Utjecaj mehaničke stratigrafije na deformacijski stil u središnjem dijelu Vanjskih Dinarida: studija kinematskim 2D modeliranjem
• Author: Philipp Balling https://orcid.org/0000-0002-8439-6369
• Author: Bruno Tomljenović
• Author: Kamil Ustaszewski https://orcid.org/0000-0002-1642-5842
• Author's institution: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Geology and Geological Engineering)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology

Abstract (english)

The External Dinarides fold-thrust belt formed during Mid-Eocene – Oligocene times by SW-propagating thrusting from the Internal Dinarides towards the Adriatic foreland. Although previously considered as structurally quite uniform, recent work of BALLING et al. (2021) reported along-strike contrasting deformation styles in two structural domains within this fold-thrust belt. The two structural domains with very contrasting deformation styles are separated by the N-S-striking dextral Split–Karlovac Fault, a 250 km long, transpressive transfer fault. The southeastern domain is characterized by a thin-skinned SW-vergent nappe stack in contrast to the northwestern domain, where a set of blind, thick-skinned top-SW thrust duplexes prevail underneath the passive NE-vergent backthrusts. To better understand possible causes that controlled these contrasting along-strike deformation styles, we firstly analysed a spatial-temporal along- and across-strike distribution of Paleo-Mesozoic lithofacies to both sides of the Split-Karlovac Fault. We further estimated the role of mechanical stratigraphy on deformation styles in this part of the fold-thrust belt. This analysis was used to construct a new 2D kinematic forward model across the northwestern backthrust-dominated domain. Our best-fit forward-modelled balanced cross section traversing the central Velebit Mtn. portrays a 75 km wide triangle zone. This zone took up at least 47 km of shortening during Eo-Oligocene times. It comprises a set of thin-skinned NE-vergent backthrusts detached in the upper Paleozoic basement atop a SW-vergent thickskinned antiformal stack detached in the lower Paleozoic Adriatic basement. The NE-vergent backthrusts likely nucleated at lateral facies boundaries related to extensional half grabens that locally formed during Permian to Middle Triassic and Late Jurassic phases of a passive margin extension. During the Eo-Oligocene shortening, the selective inversion of inherited Mesozoic half grabens boundary faults into the NE-vergent backthrusts in the northwestern domain led to the observed along-strike changes in the deformation style of the External Dinarides. Thus, our results indicate that both the variations in the mechanical stratigraphy and the pre-orogenic structural inheritance obtained during rifting and passive margin stages exert control on Eocene–Oligocene contractional structures within the central part of the External Dinarides.

• Keywords (english): mechanical stratigraphy; 2D kinematic modelling; Velebit Mt.; Dinarides
• Language: english
• Publication type: Scientific paper - Abstract
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Publication title: Knjiga sažetaka = Book of abstracts / 7. hrvatski geološki kongres s međunarodnim sudjelovanjem
• Numbering: p. 15
• p-ISSN: 1849-7713
• URN:NBN: urn:nbn:hr:169:813049
• Publication: 2023
• Conference: Title: 7. hrvatski geološki kongres s međunarodnim sudjelovanjem; Acronym: HGK; Location: Poreč, Croatia; Organizer: Hrvatsko geološko društvo; Organizer: Hrvatski geološki institut; Organizer: Sveučilište u Zagrebu, Prirodoslovno-matematički fakultet; Organizer: Sveučilište u Zagrebu, Rudarsko-geološko-naftni fakultet; Organizer: INA – Industrija nafte d.d.; Organizer: Hrvatski prirodoslovni muzej; Organizer: Sveučilište u Zagrebu, Geotehnički fakultet Varaždin; Organizer: Agencija za ugljikovodike; Start date: 2023-10-02; End date: 2023-10-04; Assembly type: Lecture
• Document URL: https://7hgk2023.hgi-cgs.hr/wp-content/uploads/2023/09/7.-HGK-book-of-abstracts.pdf
• Type of resource: Text
• Publisher: Hrvatski geološki institut
• Publishing place: Zagreb
• Access conditions: Open access
• Created on: 2023-10-27 10:27:23