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Location map illustrating the approximate extent of the area covered by this study, key well sections, and the seismic grid used. Seismic reflection profiles P95-158 (Fig. 4) and P95-103 (Fig. 5) are highlighted.
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Progradation and aggradation of the modern continental margin in northern Taranaki Basin has resulted in the deposition of a thick and rapidly accumulated Pliocene-Pleistocene sedimentary succession. It includes the predominantly muddy Giant Foresets Formation, and the underlying sandy Mangaa Formation. Investigation of the internal attributes and...
Contexts in source publication
Context 1
... than seventy seismic units, based on distinctive internal reflector configurations, have been identified and mapped within the study area (Fig.2). These have been mapped over a seismic grid covering the study area, and isopach maps have been prepared for broad divisions based on biostratigraphic stages. ...
Context 2
... two-dimensional excel-based backstripping programme was used to undertake backstripping and decompaction of the post-Miocene section of seismic reflection line P95-158 (see Fig.2 for transect location). ...
Context 3
... et al. 1988). While a full description and interpretation of these features will appear in other papers, the major architectural elements are summarised in Fig.4 (seismic reflection profile P95-103; see Fig.2 for transect location). ...
Context 4
... out the depositional geometry of the Giant Foresets Formation in particular provides an essential basis for such modeling. The upper panel is an uninterpreted (except for faults) representation of line P95-158 (see Fig. 2 for location), showing the modern shelf out to the top of the slope and the underlying sedimentary succession. The three underlying panels show successive backstripped and decompacted palinspastic restorations of the Northern Graben. ...
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Abstract: In the northern part of the Upper Rhine Graben (URG), a high-resolution seismic reflection survey was carried out on the Rhine River over a length of 80 km, and on its tributary Neckar over a length of 25 km. The seismic investigation provides new results to redefine the base of Quaternary fluvial sediments from Oppenheim upstream to the...
Citations
... In the case of Mohakatino Beach, an MTD 15-m-thick occurs 40 m stratigraphically above the sea stack feature we describe and is part of a larger mass transport unit. Hansen (1996), Helle (2003), King et al. (2011) and Masalimova et al. (2016) described the Mohakatino mass transport deposit in greater detail. Helle (2003) referred to is as Deformed Element 1 and mapped it for > 10 km inland from the coastal section and inferred that it was transported southwest into the basin as opposed to the more NW-transport direction of the enclosing Mount Messenger Formation sandstones and siltstone lithologies (Helle 2003, his fig. ...
Many sedimentary structures are the manifestation of fluid escape in sedimentary basins. This paper examines outcrop and seismic examples in upper Miocene deep-water sandstones and siltstones of north Taranaki, New Zealand. In outcrop examples of fluid escape features comprise discordant bodies within otherwise uniformly bedded surrounding stratigraphy, features characterized by steep sided, over-hanging, vertical or near-vertical margins, infilled with an assortment of poorly sorted or chaotically arranged sandstone and siltstone. Typically, these features are several metres wide and up to 20 m high in outcrop and always occur stratigraphically below a mass transport deposit (MTD). Examples of similar features from nearby 2D and 3D seismic reflection data consist of localized vertical to sub-vertical zones of disrupted reflectivity and are as much as 300 m in height and 10’s–100’s of metres in width. The structures occur in close association with the basal slide planes of seismic-scale MTDs. The close association of fluid escape structures with MTDs suggests that these features formed by the sudden loading of the sedimentary succession by the emplacement of several metre-thick overlying MTDs. We suggest recurring phases whereby the emplacement of MTDs triggered fluid escape within underlying strata and, in turn, the fluid escape contributed to further instability with potential for mobilization and transport of subsequent MTDs in a dynamic deep-water setting.
... Late Miocene to Pliocene activity in much of the Northern Taranaki Basin involved back-arc extension tectonics associated with the Hikurangi subduction zone of the Australian-Pacific plate margins. Extensional faulting within the basin formed a c. 40 km wide depocentre, known as the Northern Taranaki Graben (Hansen & Kamp, 2004a, 2004b, bordered between the Turi Fault Zone and Cape Egmont Fault Zone (Stagpoole & Funnell, 2001). The graben occupies an area of 10,000 km 2 . ...
... Ma) to Mangapanian (2.79-2.28 Ma), in early Pliocene; together with the existence of volcanic massifs of the Mohakatino Formation that influenced the way the paleogeography would affect siliciclastic sediment accumulation (Hansen & Kamp, 2002, 2004b). ...
There remains a limited understanding of the controls of pre‐existing structures on the architecture of deep‐water progradational sequences. In the Northern Taranaki Basin (NTB), New Zealand, Pliocene post‐extensional sedimentary sequences overlie Miocene back‐arc volcaniclastic units. We utilize seismic reflection datasets to investigate the relationships between the buried back‐arc mound‐shaped structures, and the spatio‐temporal changes in clinoform architecture and the associated progradational system elements within the overlying continental slope margin sequences. Our results reveal the following: (a) buried mound‐shaped structures in the northern domain of the study area, overlain by younging progression of shelf‐to‐basin prograding clinoforms; (b) folding of the deeper clinoforms that systematically decrease in magnitude with shallowing depth from the top of the seamounts; (c) overall, the N‐S‐trending continental slope margin evolves from a highly curvilinear/angular trend in the deeper clinoforms (Units 1 and 2) into a rectilinear geometry within the shallower post‐extensional intervals (Unit 3 and shallower); (d) Units 1 and 2 characterized by dominance of stacked offlap breaks and over‐steepened (7–10°) clinoform foreset slopes in the northern domain, and dominance of gently dipping foreset slopes (<6°) in the south; (e) Unit 3 shows very low (<5°) and intermediate (5–7°) foreset slopes across the entire survey; (f) in the northern domain, differential loading by prograding sequences about the buried seamounts and horst–graben structures induced a differential compaction of the deeper units, which influenced a temporal pinning of the prograding slope margin in pre‐Unit 2 times and (g) wide, closely spaced channel incision into over‐steepened slopes dominate the deeper prograding sequence in the northern domain, whereas narrower, straighter channels dominate the south. We show that the buried pre‐existing structures constitute rigid buttresses that modulated the syn‐depositional topography and post‐depositional architecture of the prograding sequences in the NTB. Our findings present a distinction in the controls on progradational sedimentation patterns between magmatic and non‐magmatic continental margins.
... Throughout the Miocene, large mounded channel and turbidite systems form a broad compensational stacking pattern (Uruski, 2008;Baur et al. 2014) succeeded by the Giant Foresets Formation (GFF). The GFF is a late-early Pliocene to recent succession of shelf to slope to basin-floor fine-grained muds, silts and sands (Beggs, 1990;Hansen and Kamp 2004a;2004b) (Fig. 2B). Seismic reflection profiles show that the GFF locally reaches thicknesses of over 2 km and is characterised by high-relief clinoforms (up to 1500 m thick; Salazar et al. 2015) that offlap in a basinward direction. ...
... Discovery of a complex and dynamic succession of deep-water sedimentary packages linked to the shelf via numerous seafloor channels over the last ~2 Myr, and following the emplacement of MTD 2, invites further inquiry into the rate and mode of sediment delivery in the present-day. It is well established that the majority of the late-early Pliocene to recent sediments underlying the present-day shelf and slope accumulated very rapidly (Beggs, 1990;Hansen and Kamp 2004a;2004b;Salazar et al. 2015) through transport of sediments from the south and east by shore-parallel and other currents Kamp, 2002, Anell andMitkandel, 2015;Salazar et al. 2015). MTD 2 emplacement is linked to periods of very high sediment supply (Omeru, 2014) but there have been few studies to document the present-day sedimentation regime. ...
Three-dimensional (3D) seismic data reveal the complex interplay between the surface topography of a c. 4405 km ³ mass transport deposit (MTD) and overlying sedimentary packages over approximately the last two million years. The data image part of the Pleistocene to recent shelf to slope to basin-floor Giant Foresets Formation in offshore western New Zealand. The MTD created substantive topographic relief and rugosity at the contemporaneous seabed, formed by the presence of a shallow basal detachment surface, and very large (up to 200 m high) intact slide blocks, respectively. Sediments were initially deflected away from high-relief MTD topography and confined in low areas. With time, the MTD was progressively healed by a series of broadly offset-stacked and increasingly unconfined packages comprised of many channel bodies and their distributary complexes. Positive topography formed by the channels and their distributary complexes further modified the seafloor and influenced the location of subsequent sediment deposition. Channel sinuosity increased over time, interpreted as the result of topographic healing and reduced seafloor gradients. The rate of sediment supply is likely to have been non-uniform, reflecting tectonic pulses across the region. Sediments were routed into deep water via slope-confined channels that originated shortly before emplacement of the MTD.
... Vertically and laterally stacked channel deposits of Channel Complex Systems 2 and 3, on the hanging-wall of the Parihaka Fault, comprise a potential reservoir for hydrocarbons generated in the Moki Formation. As thick channel deposits are observed on the hanging-wall block, they will be important for the development of petroleum systems in the northern Taranaki Basin (Armstrong, Chapman, Funnell, Allis, & Kamp, 1996;Hansen & Kamp, 2004b;Webster, O'Connor, Pindar, & Swarbrick, 2011). ...
High‐quality 3D seismic data are used to investigate the effect of the Parihaka Fault on the geometry of submarine channels in Northern Graben of the Taranaki Basin, New Zealand. The Parihaka Fault comprises four segments (S1 to S4) with variable displacements. As part of the Plio‐Pleistocene Giant Foresets Formation, the older Channel Complex Systems 1 and 2 reveal a two‐stage evolution: 1) a syn‐tectonic depositional stage with channels incising the slope during early fault growth (~4.5 Ma) and 2) a stage of sediment bypass (~3 Ma) leading to the infill of hanging‐wall depocentres. Channel Complex System 3 is syn‐tectonic relative to segment S3 and was formed at ~ 2.5 Ma. We show that the successive generation of new fault segments towards the north controlled the formation of depocentres in the study area. This occurred in association to rotation and uplift of the footwall block of the Parihaka Fault and subsidence of its hanging‐wall block, with fault activity controlling the orientation of channel systems. As a result, we observe three drainage types in the study area: oblique, transverse and parallel to the Parihaka Fault. This work is important as it shows that relay zones separating the Parihaka Fault segments had limited influence on the geometry and location of channel systems. Submarine channels were diverted from their original courses close to the Parihaka Fault and flowed transversally to fault segments instead of running through relay ramps, contrasting to what is often recorded in the literature. A plausible explanation for such a discrepancy relates to rapid progradation of the Giant Foresets Formation during the Plio‐Pleistocene, with channel complexes becoming less confined, favouring footwall incision and basinward deposition of submarine fans.
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... The sedimentary succession in the North Taranaki Graben is composed of 2 km of Cretaceous to Paleogene rocks and up to 5 km of Neogene deposits Webster et al., 2011). The Giant Foresets Formation, where paleo-pockmarks have been found, is comprised of a thick, shelf to slope to basin floor succession predominantly composed of fine-grained mudstone and siltstone derived from the South Island and transported northward by longshore drift and ocean currents (Hansen and Kamp, 2002, 2004a, 2004bAnell and Midtkandal, 2015;Salazar et al., 2015). The paleo-pockmarks are located on the lower part of a clinoform set downlapping onto a Late Miocene reflection and interpreted as a slope fan (Salazar et al., 2015). ...
After the first discovery of seabed pockmarks in the 1960s and 1970s, many examples of both modern and ancient pockmarks have been reported from sedimentary basins around the world. The exact mechanisms and fluids involved in pockmark formation are still subject to debate with many studies inferring that pockmark formation is a direct indication of hydrocarbon expulsion. This study provides the first description of a buried Pliocene paleo-pockmark field in the offshore Taranaki Basin, New Zealand. The paleo-pockmarks are located approximately 1.2–1.3 km below the seabed and are well imaged by three-dimensional seismic data. Their spatial density and size increases towards the distal portions of the fan, and they vary in size between 45 and 580 m in diameter and 2–35 ms TWT. Pockmark size is inversely correlated with the fan thickness in the study area. Detailed analysis rules out any links with faulting, while the relationship with fan variations in the depositional thickness suggests porewater expulsion during overburden progradation as the most likely cause of the paleo-pockmarks. A model is proposed in which rapid sediment loading generated overpressure which was greatest on the proximal fan due to the lateral gradient in the sediment load imposed by clinoform progradation. Fluids were consequently forced towards the distal fan where, eventually, the pore pressure exceeded the fracture gradient of the seal. The implications of this study are that not all pockmarks can be used as evidence for hydrocarbon expulsion in frontier regions and care should be taken to examine the subsurface context, plumbing systems and any associated acoustic anomalies before concluding on the pockmark origin.
... The latest Miocene to Pliocene Giant Foresets Formation was deposited during progradation of a major slope to basin succession (Hansen & Kamp, 2004). The formation in the study area is of Pliocene age, and has a very characteristic appearance on seismic data, dominated by prograding clinoform geometries (Figs 3 and 5). ...
Industry 2D and 3D seismic data across the North Taranaki Basin displays two listric normal faults that formed during Pliocene shelf edge clinoform progradation. The faults die out in the down-transport direction with no evidence for contractional structures, except for two small thrust faults in one narrow zone. When active the detachment lay at depths of about 1000 m below the seafloor. The overlying section had high initial porosities (30-60%). It is estimated that loss of about 17-20% pore volume by lateral compaction, and fluid expulsion over a distance of about 4-6 km in the transport direction occurred in place of folding and thrusting. Seismic and well evidence for abnormally highly compacted shales suggests there is about 6% less porosity than expected for in the pre-kinematic section, which possibly represents a residual of the porosity anomaly caused by lateral compaction. The observations indicate significant shortening (~20%) by lateral compaction and probably some layer parallel thickening are important deformation mechanisms in near-surface deepwater sediments that needs to be incorporated into shortening estimates and ‘balanced’ cross-sections. A key factor in listric fault initiation near the base of slope is inferred to be transient, increased pore fluid pressure due to lateral expulsion of fluids from beneath the prograding Giant Foresets Formation. This article is protected by copyright. All rights reserved.
Megaclasts transported within submarine landslides can erode the substrate, can influence the flow which transports them, and, if they form seafloor topography, can influence subsequent flows and their deposits. We document grooves up to 40 km long formed by megaclasts carried in submarine landslides which scoured tens of metres deep into the contemporaneous substrate of the deep water Taranaki Basin, New Zealand. A 1,925 km2 3D seismic reflection survey records six mass transport deposits (MTDs) interbedded with turbidites. Here, we focus on three MTDs, labelled A (oldest), B and C (youngest). MTD-A features megaclasts that internally have coherent parallel strata, and formed striations 4-15 km long and 2-3 km wide, with protruding megaclasts that are onlapped by younger sediments. The seafloor expression of these megaclasts partially obstructed the submarine landslide that created MTD-B. MTD-B contains megaclasts that incised through the rugose topography of the underlying MTD-A, and formed divergent grooves on the basal surface of MTD-B (8-40 km long and 200-250 m wide) which suggest radial flow expansion where flows exited topographic confinement. MTD-C features grooves 2-6 km long and 100-200 m wide that terminate at megaclasts which internally are characterised of highly deformed reflectors surrounded by a chaotic matrix. This study directly links megaclasts to the grooves they form, and demonstrates that markedly different styles of scouring and resultant grooves can occur in closely-related MTDs.
