Neogene-Quaternary architecture and sedimentary processes on an isolated carbonate-fed deep-water basin (Fairway Basin, Southwest Pacific)

Type Article
Date 2019-07
Language English
Author(s) Pattier France1, 2, 3, Etienne S.1, 2, Collot J2, Patriat MartinORCID2, 3, Tournadour Elsa1, 2, Roest WalterORCID3, Rouillard P.2
Affiliation(s) 1 : ADECAL Technopole, ZoNéCo Research Program, Nouméa, New Caledonia
2 : Geological Survey of New Caledonia, DIMENC, BP 465, 98845 Nouméa, New Caledonia
3 : Ifremer, Géosciences Marines, CS 10070, 29280 Plouzané, France
Source Marine Geology (0025-3227) (Elsevier BV), 2019-07 , Vol. 413 , P. 27-47
DOI 10.1016/j.margeo.2019.04.003
WOS© Times Cited 1
Keyword(s) Deep-water carbonates, Submarine landslides, Turbidites, Polygonal faulting, Fluid escape, Fairway Basin
Abstract

The Fairway Basin is an intracratonic deep-water basin inherited from cretaceous rifting, perched between the Lord Howe Rise and the New Caledonia Basin in the Southwest Pacific. Its originality lies in its atypical present-day physiography and its carbonate-dominated sedimentary setting since the Miocene. Although very limited well controls are available, its overall structure, seismic stratigraphy and architecture are relatively well known. However, little is known on the detailed sedimentary processes controlling its recent infill. Its remote location from any major clastic sediment sources provides a great setting to study deep-water carbonate sedimentary processes. In this paper, we propose a detailed analysis of surface morphologies based on existing multibeam and subbottom echosounding data together with an analysis of the Neogene to Quaternary basin-fill based on seismic reflection data. This allows us to discuss active sedimentary processes, notably gravity flow processes which are thought to be active since the Middle Miocene. These processes are evidenced by both surface and subsurface features, such as submarine canyons, channels and lobes, composite scarps and mass transport deposits (MTDs). In the northern part of the basin, a 400 km-long axial turbidite system is developed close to the Lansdowne Bank, a partly drowned isolated carbonate platform, where present-day sediment remobilisation seems to be essentially sourced from intra-slope instabilities. These reworked sediments extend over an area of 16,000 km2. Along with this axial turbidite system, seismic data show two main mass transport complexes (covering an area of ca 20% of the basin's surface) originating from the slopes of the basin. The potential triggering mechanisms of MTDs of the northern complex might be directly attributed to overloading and high slope values of the Lansdowne Bank area (>1.5°). For the southern complex, surface slope values are lower (<1.4°), and the role of fluid migration and escape is discussed. The Fairway Basin indeed shows strong evidences for fluid generation (e.g. polygonal faulting, pockmarks, presence of a widespread Opal-A/Opal-CT diagenesis-related bottom simulating reflectors) and fluid overpressures.

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