Kerguelen Plateau: A volcanic passive margin fragment?

The 21–25-km-thick crust of the southern Kerguelen Plateau consists of three units: (1) a ≤ 2.3-km-thick sedimentary cover; (2) a 3–6-km-thick basaltic layer with velocities ranging from 4.5 to 6.2 km/s; and (3) a 15–17-km-thick lower crust with velocities from 6.6 to 6.9 km/s, including a 3–6-km-thick transition zone located at the base of the crust. The low-velocity transition zone has an average velocity of 6.7 km/s and exhibits several internal wide-angle reflections. The velocity-depth structure of the crust differs significantly from that of other hotspot-related oceanic plateaus and suggests that the southern Kerguelen Plateau may be a fragment of a volcanic passive margin composed of a thinned continental crust overlain by basalt flows.

[1]  O. Eldholm,et al.  Large igneous provinces: crustal structure, dimensions, and external consequences , 1994 .

[2]  J. Mutter,et al.  Variations in thickness of layer 3 dominate oceanic crustal structure , 1993 .

[3]  R. White,et al.  Oceanic crustal thickness from seismic measurements and rare earth element inversions , 1992 .

[4]  A. Saunders,et al.  Lower Cretaceous Volcanic Rocks on Continental Margins and Their Relationship to the Kerguelen Plateau , 1992 .

[5]  M. Schaming,et al.  Basement reflectors in the Kerguelen Plateau, south Indian Ocean: Indications for the structure and early history of the plateau , 1990 .

[6]  Zhi Gang Li,et al.  Seismic stratigraphy of the Raggatt Basin, southern Kerguelen Plateau: Tectonic and paleoceanographic implications , 1990 .

[7]  R. White,et al.  Magmatism at rift zones: The generation of volcanic continental margins and flood basalts , 1989 .

[8]  R. Mithal,et al.  A Low-Velocity Zone Within the Layer 3 Region of 118 Myr Old Oceanic Crust In the Western North Atlantic , 1989 .

[9]  R. White,et al.  The Hatton Bank continental margin—II. Deep structure from two-ship expanding spread seismic profiles , 1989 .

[10]  M. Coffin,et al.  New findings from the Kerguelen Plateau , 1986 .

[11]  N. Watkins,et al.  Kerguelen: Continental Fragment or Oceanic Island? , 1974 .

[12]  Robert B. Smith,et al.  Seismic traveltime inversion for 2-D crustal velocity structure , 1992 .

[13]  J. Royer,et al.  Jurassic to Eocene plate tectonic reconstructions in the Kerguelen Plateau region , 1992 .

[14]  C. Alibert.  15. MINERALOGY AND GEOCHEMISTRY OF A BASALT FROM SITE 738: IMPLICATIONS FOR THE TECTONIC HISTORY OF THE SOUTHERNMOST PART OF THE KERGUELEN PLATEAU1 , 1991 .

[15]  Zhi Gang Li,et al.  The Raggatt Basin: a mid-ocean sedimentary basin on the Kerguelen Plateau , 1987 .