@article{fdi:43135,
  title = {{D}eep structure of the northern {K}erguelen {P}lateau and hotspot-related activity},
  author = {{C}harvis, {P}hilippe and {R}ecq, {M}. and {O}perto, {S}. and {B}refort, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}eismic refraction profiles were carried out in 1983 and 1987 throughout the {K}erguelen {I}sles (southern {I}ndian {O}cean, {T}erres {A}ustrales & {A}ntarctiques {F}ranqaises, {TAAF}) and thereafter at sea on the {K}erguelen {H}eard {P}lateau during the {MD}66/{K}e{OBS} cruise in 1991. {T}hese profiles substantiate the existence of oceanic type crust beneath the {K}erguelen {H}eard {P}lateau stretching from 46°s to 55°{S}, including the archipelago. {S}eismic velocities within both structures are in the range of those encountered in 'standard' oceanic crust. {H}owever, the {K}erguelen {I}sles and the {K}erguelen {H}eard {P}lateau differ strikingly in their velocity depth structure. {U}nlike the {K}erguelen {I}sles, the thickening of the crust below the {K}erguelen {H}eard {P}lateau is caused by a 17 km thick layer 3. {V}elocities of 7.4 km s-1 or so within the transition to mantle zone below the {K}erguelen {I}sles are ascribed to the lower crust intruded and/or underplated by upper mantle material. {T}he crust mantle boundary below the {K}erguelen {H}eard {P}lateau is abrupt and devoid of any underplated material. {T}he difference in structure between the northern edge of the {K}erguelen {P}lateau (including the archipelago) and the {K}erguelen {H}eard {P}lateau may be related to variability of the time dependent hotspot activity. {T}he {K}erguelen {H}eard {P}lateau was emplaced during the {C}retaceous time (110 {M}a) when the volcanic output rate of the {K}erguelen {P}lateau and the {N}inetyeast {R}idge was high (as well as high potential temperature). {T}he northern most {K}erguelen {P}lateau and the archipelago were emplaced during {T}ertiary time (40 45 {M}a), as the volcanic output rate reduced. {F}urthermore, intraplate volcanism continued in the {K}erguelen archipelago for at least 40 {M}a. {T}he isostatic compensation of the {K}erguelen {I}sles and the {K}erguelen {H}eard {P}lateau is achieved by low density mantle material, as shown by refraction and geoid studies. {T}he velocity depth structure below the {K}erguelen {I}sles is similar to that found below intraplate oceanic islands such as {H}awaii. {D}espite the differences in age, the crust below {I}celand (0{M}a) and the {K}erguelen {P}lateau (100-120 {M}a) are strikingly akin. {T}he similarity between the {K}erguelen {H}eard {P}lateau and {I}celand, then, strongly supports a similar origin for both structures, the {K}erguelen {H}eard {P}lateau being a fossil equivalent of present‐day {I}celand. {C}rustal thickening beneath the {K}erguelen‐{H}eard {P}lateau, which may result from an {I}celand type setting (i.e. an active spreading centre over a hotspot), is mostly produced by thickening of layer 3, layer 2 representing 25 per cent only of the thickness of the igneous crust. {T}he {K}erguelen {I}sles, despite the initial volcanism near the active {S}outheast {I}ndian {R}idge, behave as a midplate volcanic island and are definitely not representative of the whole {K}erguelen {P}lateau structure.},
  keywords = {{TECTONIQUE} {DE} {PLAQUES} ; {GEOLOGIE} {STRUCTURALE} ; {BATHYMETRIE} ; {SISMIQUE} {A} {REFRACTION} ; {KERGUELEN}},
  booktitle = {},
  journal = {{G}eophysical {J}ournal {I}nternational},
  volume = {122},
  numero = {3},
  pages = {899--924},
  ISSN = {0956-540{X}},
  year = {1995},
  DOI = {10.1111/j.1365-246{X}.1995.tb06845.x},
  URL = {https://www.documentation.ird.fr/hor/fdi:43135},
}