Fault-induced deformation in a poorly consolidated, siliciclastic growth basin: A study from the Devonian in Norway

The Late Triassic outcrops on southern Edgeøya, East Svalbard, allow a multiscale study of syn-sedimentary listric growth faults located in the prodelta region of a regional prograding system. At least three hierarchical orders of growth faults have been recognized, each showing different deformation mechanisms, styles and stratigraphic locations of the associated detachment interval. The faults, characterized by mutually influencing deformation envelopes over space-time, generally show SW-to SE-dipping directions, indicating a counter-regional trend with respect to the inferred W-NW directed progradation of the associated delta system. The down-dip movement is accommodated by polyphase deformation, with the different fault architectural elements recording a time-dependent transition from fluidal-hydroplastic to ductile-brittle deformation, which is also conceptually scale-dependent, from the smaller-(3rd order) to the larger-scale (1st order) end-member faults respectively. A shift from distributed strain to strain localization towards the fault cores is observed at the meso to microscale (<1 mm), and in the variation in petrophysical parameters of the litho-structural facies across and along the fault envelope, with bulk porosity, density, pore size and microcrack intensity varying accordingly to deformation and reworking intensity of inherited structural fabrics. The second-and third-order listric fault nucleation points appear to be located above blind fault tip-related monoclines involving cemented organic shales. Close to planar, through-going, first-order faults cut across this boundary, eventually connecting with other favourable lower-hierarchy fault to create seismic-scale fault zones similar to those imaged in the nearby offshore areas. The inferred large-scale driving mechanisms for the first-order faults are related to the combined effect of tectonic reactivation of deeper Palaeozoic structures in a far field stress regime due to the Uralide orogeny, and differential compaction associated with increased sand sedimentary input in a fine-grained, water-saturated, low-accommodation, prodeltaic depositional environment. In synergy to this large-scale picture, small-scale causative factors favouring second-and third-order faulting seem to be related to mechanicalrheological instabilities related to localized shallow diagenesis and liquidization fronts.--

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Section: Resultsmentioning

confidence: 99%

Architecture, deformation style and petrophysical properties of growth fault systems: the Late Triassic deltaic succession of southern Edgeøya (East Svalbard)

et al. 2018

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“…The mixed zone consists of variably deformed, entrained and attenuated beds forming continuous smears along the fault trace, resulting in a largely homogenized zone with lithological mixing down to the grain scale (see e.g. Balsamo, Bezerra, Vieira, & Storti, 2013;Bense & Person, 2006;Braathen et al, 2013;Heynekamp et al, 1999;Loveless et al, 2011;Mozley & Goodwin, 1995;Rawling & Goodwin, 2003. According to this general framework, we subdivide the investigated fault envelopes into fault architectural elements (AE; Figure 4a,b): 1) hanging wall damage zone (HWDZ), 2) hanging wall mixing zone (HWMZ), 3) fault core zone (CZ), 4) footwall mixing zone (FWMZ) and 5) footwall damage zone (FWDZ).…”

Section: Litho-structural Faciesmentioning

confidence: 99%

Sedimentary architecture during Carboniferous rift initiation – the arid Billefjorden Trough, Svalbard

Smyrak-Sikora

Johannessen²,

Olaussen³

et al. 2018

JGS

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When, in March 2011, I entered the building of the University Centre in Svalbard (UNIS) my first thought was:"I want to work here". This dream came true only a year later when I started my long but very rewarding journey through the PhD project. Firstly, I would like to thank my supervisor Snorre Olaussen for offered chance to develop this exciting project in Arctic rift basin geology, his patience and trust. Transition from research conducted in structural geology of metamorphic rocks to basin analysis was not easy and Snorre always served with the guidance, help and tutoring. Huge acknowledgments go to Alvar Braathen, who has introduced me to the outcrops of Billefjorden and Edgeøya, and always offered great support and advice. William Helland Hansen and Jan Inge Faleide are acknowledged for their supervision on the project. I strongly appreciate the scientific freedom and multiple possibilities for development and collaboration I had during the research.

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“…Black frame in lower left inset locates the Barents Sea on the Norwegian continental shelf. Abbreviations: A -Altafjorden, AFC -Asterias Fault Complex, Akf -Akkarfjord fault, AsW -Altenes tectonic window, AW -Alta-Kvaenangen tectonic window, BFC -Bjørnøyrenna Fault Complex, BKFC -Bothnian-Kvaenangen Fault Complex, BSFC -Bothnian-Senja Fault Complex, FTZ -Fugløya transfer zone, GL -Gjesvaer Low, He -Helnes, K -Kvaløya, KF -Kokelv Fault, L -Langfjorden, Lf -Laksvatn fault, Lg -Lygenfjorden, LR -Lofoten Ridge, LVF -Langfjorden-Vargsundet fault, Ma -Magerøya, Mf -Magerøysundet fault, MFC -Måsøy Fault Complex, NFC -Nysleppen Fault Complex, NP -Nordkinn Peninsula, PP -Porsanger Peninsula, Re -Repparfjorden, Rf -Rolvsøya fault, Rg -Ryggefjorden, Ri -Ringvassøya, RLFC -Ringvassøya-Loppa Fault Complex, Rv -Revsbotn, RW -Repparfjord-Komagfjord tectonic window, S -Sørkjosen, SB -Sørvaer Basin, Se -Seiland, SFZ -Senja Fracture Zone, SISZ -Sørøya-Ingøya shear zone, Sj -Sjernøya, Sn -Snøfjorden, sNB -southwesternmost Nordkapp basin, SP -Svaerholt Peninsula, SSB -Senja Shear Belt, Sø -Sørøya, TFFC -Troms-Finnmark Fault Complex, TKFZ -Trollfjorden-Komagelva Fault Zone, Tu -Tufjorden, V -Vargsundet, Va -Vannøya, VP -Varanger Peninsula, VVFC -Vestfjorden-Vanna Fault Complex. » splays of the TKFZ and associated fault strands die out southeast of the Troms-Finnmark Fault Complex, and WNW-ESE-striking faults exposed onshore the island of Magerøya are part of the TKFZ and associated fault system (fault-tip) process zone (Vermilye & Scholz, 1988;Braathen et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Late Devonian–Carboniferous faulting and controlling structures and fabrics in NW Finnmark

Koehl¹,

Bergh²,

Osmundsen³

et al. 2019

NJG

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In the SW Barents Sea, Devonian-Carboniferous collapse led to the formation of major basins and faults, e.g., the Hammerfest Basin bounded by the Troms-Finnmark Fault Complex, and rhomboid-to sigma-shaped (half-)grabens on the Finnmark Platform. High-resolution aeromagnetic and bathymetry data from the shallow shelf show that analogue fault systems are present in coastal and onshore areas of NW Finnmark. We provide new documentation for the Langfjorden-Vargsundet fault, a post-Caledonian, NW-dipping, zigzag-shaped, margin-parallel fault complex consisting of alternating linear to sub-linear, NNE-SSW-and ENE-WSW-striking, down-NW normal fault segments. This fault formed as an extensional splay-fault of inverted, Caledonian, brittle-ductile thrusts, e.g, the Talvik and Kvenklubben faults, which the fault eventually truncated and offset. In northern Finnmark, the Langfjorden-Vargsundet fault is offset laterally by up to 28 km by a system of WNW-ESE-trending faults notably including potential segments and splays of the Trollfjorden-Komagelva Fault Zone, a reactivated Neoproterozoic, margin-orthogonal transfer fault, separating NW Finnmark from the eastern Finnmark Platform. This fault system likely dies out westwards, and portions of the system's process zone may crop out on the island of Magerøya. Similarly, the WNW-ESE-to ENE-WSW-striking Akkarfjord fault offsets the Langfjorden-Vargsundet fault by c. 2 km left-laterally. This fault may have formed as a conjugate to the Trollfjorden-Komagelva Fault Zone in Neoproterozoic (Timanian?) times. Steeply NW-plunging, upright and gently NE-plunging, inclined folds in Archaean-Palaeoproterozoic basement rocks and margin-parallel Caledonian thrusts may have controlled the formation and geometry of post-Caledonian faults. A Late Devonian-Carboniferous age for the Langfjorden-Vargsundet fault is supported by geochronological dating of onshore dykes and fault gouge, and by syn-tectonic sedimentary wedges along the offshore extension of the Langfjorden-Vargsundet fault. Mini-basins bounded by the Langfjorden-Vargsundet fault on the Finnmark Platform and on the shallow shelf, e.g., the Ryggefjorden trough, may represent analogues to deep, offshore, Devonian-Carboniferous basins, like the Nordkapp Basin, prior to the deposition of late Palaeozoic evaporites.

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Fault-induced deformation in a poorly consolidated, siliciclastic growth basin: A study from the Devonian in Norway

Cited by 18 publications

References 57 publications

Architecture, deformation style and petrophysical properties of growth fault systems: the Late Triassic deltaic succession of southern Edgeøya (East Svalbard)

Architecture, deformation style and petrophysical properties of growth fault systems: the Late Triassic deltaic succession of southern Edgeøya (East Svalbard)

Sedimentary architecture during Carboniferous rift initiation – the arid Billefjorden Trough, Svalbard

Late Devonian–Carboniferous faulting and controlling structures and fabrics in NW Finnmark

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