Depositional systems in multiphase rifts: seismic case study from the Lofoten margin, Norway

Abstract

The evolution of depositional systems in multiphase rifts is influenced by the selective reactivation of faults between subsequent rift phases. The Middle Jurassic to Palaeocene tectonic history of the Lofoten margin, a segment of the North Atlantic rift system, is characterised by three distinct rift phases separated by long (>20 Myr) inter‐rift periods. The initial rift phase comprised a distinct fault initiation and linkage stage, whereas the later rift phases were characterised by selective reactivation of previously linked through‐going faults which resulted in immediate rift climax. Using 2‐D and 3‐D seismic reflection data in conjunction with shallow core data we present a 100 Myr record of shallow to deep marine depositional environments that includes deltaic clinoform packages, slope aprons and turbidite fans. The rapid re‐establishment of major faults during the later rift phases impacts on drainage systems and sediment supply. Firstly, the immediate localisation of strain and accumulation of displacement on few faults results in pronounced footwall uplift and possible fault block rotation along those faults, which makes it more likely for any antecedent fault‐transverse depositional systems to become reversed. Secondly, any antecedent axially‐sourced depositional systems that are inherited from the foregoing rift phase(s) are likely to be sustained after reactivation because such axial systems have already been directed around fault tips. Hence, the immediate localisation of strain through selective reactivation in the later rift phases restricts fault‐transverse sediment supply more than axial sediment supply, which is likely to be a key aspect of the tectono‐sedimentary evolution of multiphase rifts.

Strike‐slip reactivation of segmented normal faults: Implications for basin structure and fluid flow

“…Normal fault systems are a critical element of extensional sedimentary basins, being the primary controls on basin boundaries, geometry, physiography, accommodation, sediment routing and fluid flow (e.g. Ebinger, Deino, Tesha, Becker, & Ring, ; Gawthorpe & Leeder, ; Henstra, Gawthorpe, Helland‐Hansen, Ravnås, & Rotevatn, ; Henstra et al., ). Over the past several decades, there has been considerable research into the development of normal faults and extensional sedimentary basins (e.g.…”

Evolution of drainage, sediment‐flux and fluvio‐deltaic sedimentary systems response in hanging wall depocentres in evolving non‐marine rift basins: Paleogene of Raoyang Sag, Bohai Bay Basin, China

“…The deep basin is bounded along the margins by "uplifts" or horst-block highs that provide sediment to the basin. In terms of size, the Raoyang Sag is comparable to the Tucano Basin of Brazil, or the Lofoten margin of Norway (e.g., De Souza Rodrigues & Da Silva, 2018;Henstra et al, 2016). In the north, the Raoyang Sag is bound by the Baxian Sag, and to the south, the Raoyang Sag connects with a structural high, the Shenze Lower-Uplift (Cui, Li, & Li, 2005;Liu et al, 2002;Sun et al, 2004;Figure 1b).…”

“…(Figure 10). Both of and Henstra et al (2016) emphasize the influence of flow confinement in the transverse systems on the development of axial sedimentation. Reduction in sediment supply to the downstream delta A occurred causing Delta A to regress towards the rift margin.…”

“…The interactions between these three systems are a function of a variety of variables, including basin geometry, subsidence rate, sediment discharge and catchment morphology and size (e.g., Leeder & Gawthorpe, 1987;Gawthorpe & Leeder, 2000). However, most detailed studies to date focus either on transverse hanging wall drainages versus axial drainage evolution, or the manner in which the basin's different footwall drainages interact (e.g., Bridge & MacKey, 1993;Cope et al, 2010;Henstra, Gawthorpe, Helland-Hansen, Ravnås, & Rotevatn, 2016;Leeder & Gawthorpe, 1987;Leeder, Mack, & Salyards, 1996;Mack, Seager, & Leeder, 2006;Marr, Swenson, Paola, & Voller, 2000). Examples of such interactions include subsidence rate control on the location of axial depositional systems, or increased interactions of transverse depositional systems with axial depositional systems during the late syn-rift and post-rift stages (e.g., Bridge & Mackey, 1993;Elliott et al, 2015;Gawthorpe & Leeder, 2000;Leeder & Jackson, 1993;Leeder & Mack, 2001;Muravchik, Bilmes, & D'elia, 2014;Muravchik, Gawthorpe, & Sharp, 2018).…”

“…Studies of these interactions have led to significant advances in understanding how clastic depositional systems distribute and evolve during different rift stages. This lack of attention is likely due to the thin, fine-grained nature of hanging-wall dipslope deposits, which often requires high resolution, more broadly distributed data to fully investigate these deposits (e.g., Gawthorpe & Colella, 1990;Henstra et al, 2016;Kim, Petter, Straub, & Mohrig, 2014;Muravchik et al, 2014). However, most detailed studies to date focus either on transverse hanging wall drainages versus axial drainage evolution, or the manner in which the basin's different footwall drainages interact (e.g., Bridge & MacKey, 1993;Cope et al, 2010;Henstra, Gawthorpe, Helland-Hansen, Ravnås, & Rotevatn, 2016;Leeder & Gawthorpe, 1987;Leeder, Mack, & Salyards, 1996;Mack, Seager, & Leeder, 2006;Marr, Swenson, Paola, & Voller, 2000).…”