Mass transport deposit (MTD) relief as a control on post-MTD sedimentation: Insights from the Taranaki Basin, offshore New Zealand. (October 2020)

• Record Type: Journal Article
• Authors: Nwoko, Jefferson; Kane, Ian; Huuse, Mads
• Is Part Of: Marine and petroleum geology. Volume 120(2020)
• Publication Date: 2020-10
• Subjects: Mass transport deposits (MTDs) -- Turbidite -- Stratigraphic trap -- Seismic facies; Submarine geology -- Periodicals; Petroleum -- Geology -- Periodicals; Géologie sous-marine -- Périodiques; Pétrole -- Géologie -- Périodiques; Petroleum -- Geology; Submarine geology; Periodicals; Electronic journals; 551.468
• DOI: 10.1016/j.marpetgeo.2020.104489
• Languages: English
• ISSNs: 0264-8172

Abstract

Abstract: Mass transport deposits (MTDs) can affect the routing of turbidite systems and their resultant sedimentary architecture. With the aid of a high-quality 3D-seismic reflection dataset a buried Pleistocene MTD has been identified in the deep-water Taranaki Basin. Three MTD seismic facies have been identified and fall within three morphological domains – extensional, translational and contractional areas. Thickness relationships between the MTD and the overburden deposits were investigated quantitatively and matched using TWT-thickness maps. The results reveal that in proximal and distal areas with significant MTD relief, occupied by megaclasts and folded facies respectively, post-MTD accommodation is dominated by small 'micro-basins' with tortuous sediment pathways. In contrast the translational domain, containing homogeneous MTD facies, hosts larger low-relief basins. These characteristics can be used to define two main types of depositional topography: Type I, High-relief depositional topography, is observed prominently in the headwall and toe regions of MTDs, resulting in loosely-connected and isolated ponds of sediment; Type II, Low -relief depositional topography, is observed in the translational domain where the effects of sediment loading are clearly observed. Turbidite sandstone distribution affected by Type I topography, is characterised by irregular pinch-outs which present a significant risk for stratigraphic trapping whereas Type II topography may form overlying sedimentary bodies which are more extensive. Turbidite deposits in both settings are prone to syn-depositional remobilisation on top of the MTD, which may introduce considerable heterogeneity, particularly at reservoir margins. Highlights: Two types of MTD topography are presented linked to slide/toe morphology domains. Type 1 – high-relief depositional topography with rugose surface. Type 2 – low-relief depositional topography characterised by smooth upper surface. Three facies-overburden distributions related to both topography types identified. Overburden modification by MTD surface relief yields three healed topography styles.