The field and remote sensing analysis of the Kerguelen Archipelago structure, Indian Ocean

Abstract

1The Kerguelen Archipelago is part of an oceanic plateau with a complex history. Little work has been done on the tectonics of the onshore areas, even though the extensive outcrop renders the islands especially good for structural work. We present the results of three field campaigns and remote sensing analysis carried out in the main Kerguelen Island, around Val Travers valley and Mt Ross volcano (Central Plateau) and in the Rallier du Baty peninsula (SW part of the archipelago). We have mapped faults, fracture sets, and the location and geometry of intrusive bodies. We found that the plateau basalt lavas that make up most of the area are densely fractured, crossed by many veins, dykes and some small faults. This work provides a general framework for the structure of Kerguelen Archipelago that is dominated by 110°-striking faults and veins, dyke swarms and an alignment of recent central volcanoes, which have formed in N-S to NNW-SSE directed extensional stress field. The other structures are fractures, veins and dykes which strike 130°-150°, 000° and 030°-050°. They are likely related to transform faults of the Indian oceanic crust and to faults of the north Kerguelen Plateau (offshore basement of the archipelago). These buried structures were likely re-activated by a low magnitude stress field.

Seafloor and Ocean Crust Structure of the Kerguelen Plateau from Marine Geophysical and Satellite Altimetry Datasets

“…Other studies used the Gravity Recovery and Climate Experiment (GRACE) mission for detecting trends and variations in the ice-sheet mass balance by evaluating gravity signals [44]. Furthermore, Mathieu et al [45] combine the SRTM DEM, remote sensing data and geological sampling to clarify seafloor structures.…”

Integrating remote sensing and Super-Low Frequency electromagnetic technology in exploration of buried faults

“…Recently, much more remote sensing techniques can supply multiplicate methods and enrich the direct information to reflect the features of many geological structures intuitively and effectively. Especially the tectonic tone, figuration, texture, physiognomy, fault cliff and terminal facet and so on are the manifest tectonic identification signs in the remote sensing image [4][5][6]. Therefore the remote sensing techniques have widely been used to explore buried fault.…”

Stable isotope study of rainfall, river drainage and hot springs of the kerguelen archipelago, SW Indian Ocean

“…A prolonged record of continuous magmatic activity has been documented for the Kerguelen archipelago (Fig 1A; Giret, 1990;Weis and Giret, 1994;Weis et al, 1998;Mathieu et al, 2011), but little attention has been paid to the type of hydrothermal system responsible for the generation of hot springs and fumarolic activity. The volcanic archipelago of Kerguelen hosts several geothermal centers expressed by continuous fumaroles and thermal springs (Fig.…”

“…However, there is a lack of observational data cataloguing recent volcanic eruptions due to the remoteness of the Kerguelen archipelago. Various authors have interpreted local magmatic petrogenesis and temperature in the Kerguelen archipelago (Giret, 1990;Luyendick and Rennick, 1977;Weis and Giret, 1994;Weis et al, 1998;Mathieu et al, 2011). Fewer authors have focused on seawater and meteoric water exchanged by hydrothermal water/rock interaction of geothermal systems associated with magma (Ballestracci and Nougier, 1984;Delorme et al, 1994;Verdier, 1989) and almost very few papers deal with present-day hydrology (Berthois and Le Provost, 1971), hydrogeology or geothermal fluids (δ 13 C CO2: Javoy et al, 1982).…”