| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Journal of Petrology | Volume 43 | Number 7 | Pages 1177-1205 | 2002
© Oxford University Press 2002
Mantle Sources and the Highly Variable Role of Continental Lithosphere in Basalt Petrogenesis of the Kerguelen Plateau and Broken Ridge LIP: Results from ODP Leg 183
1DEPARTMENT OF CIVIL ENGINEERING AND GEOLOGICAL SCIENCES, UNIVERSITY OF NOTRE DAME, NOTRE DAME, IN 46556, USA
2SCHOOL OF OCEAN AND EARTH SCIENCE AND TECHNOLOGY, UNIVERSITY OF HAWAII, HONOLULU, HI 96822, USA
Ocean Drilling Program (ODP) Leg 183 was designed to investigate the origin and evolution of the large igneous province composed of the Kerguelen Plateau and Broken Ridge. Of the eight sites drilled, basalt was recovered from seven, five on the plateau and two on Broken Ridge. We present results from four of these sites, 1136, 1138, 1141 and 1142. Although this large igneous province is interpreted as being derived from the Kerguelen mantle plume, the geochemical characteristics of basalt from some parts of the province indicate a role for continental lithosphere. The 118119 Ma basalt flows recovered in the Southern Kerguelen Plateau (Site 1136) have a more subtle continental signature than shown by basalt at Leg 119 Site 738. A continental signature is absent in the 100101 Ma tholeiitic basalts at Site 1138 in the Central Kerguelen Plateau (CKP); their age-corrected NdSrPb isotopic values and incompatible element ratios are similar to those estimated for primitive mantle. These flows may represent a major mantle source in the Kerguelen starting-plume head. The 20 basalt units identified are a product of magma chamber replenishment, fractional crystallization, and resorption of crystallizing phases. The topmost unit, Unit 1, is a dacite that evolved from a basalt magma similar to those represented by Units 322; unlike the basalts the dacite magma was probably influenced by continental material. Middle Cretaceous (
95 Ma) lavas of Sites 1141 and 1142 on Broken Ridge (originally part of the CKP) are alkalic, with one exception (a tholeiite at the base of Site 1142). The alkalic lavas may represent a late-stage cap or carapace of relatively low-degree partial melts that overlies a thick tholeiitic lava pile. The tholeiite and pebbles from the top of a probable talus deposit (Unit 2) at Site 1142 have geochemical signatures consistent with a minor contribution from continental material. This signature is absent in the other units from these two sites, which have ocean-island-like incompatible element ratios and age-corrected isotopic characteristics similar (but not identical) to those proposed for the post-30 Ma Kerguelen plume. These alkalic basalts may be the purest representatives of the Cretaceous plume tail composition yet found.
KEY WORDS: assimilation; basalt; large igneous province; mantle plume; Ocean Drilling Program
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
W. J. Chazey III and C. R. Neal Large igneous province magma petrogenesis from source to surface: platinum-group element evidence from Ontong Java Plateau basalts recovered during ODP Legs 130 and 192 Geological Society, London, Special Publications, January 1, 2004; 229(1): 219 - 238. [Abstract] [PDF] |
||||
![]() |
R. A. DUNCAN A Time Frame for Construction of the Kerguelen Plateau and Broken Ridge J. Petrology, July 1, 2002; 43(7): 1109 - 1119. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. F. COFFIN, M. S. PRINGLE, R. A. DUNCAN, T. P. GLADCZENKO, M. STOREY, R. D. MULLER, and L. A. GAHAGAN Kerguelen Hotspot Magma Output since 130 Ma J. Petrology, July 1, 2002; 43(7): 1121 - 1137. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. J. MAHONEY, D. W. GRAHAM, D. M. CHRISTIE, K. T. M. JOHNSON, L. S. HALL, and D. L. VONDERHAAR Between a Hotspot and a Cold Spot: Isotopic Variation in the Southeast Indian Ridge Asthenosphere, 86{degrees}E-118{degrees}E J. Petrology, July 1, 2002; 43(7): 1155 - 1176. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. A. FREY, D. WEIS, A. YU. BORISOVA, and G. XU Involvement of Continental Crust in the Formation of the Cretaceous Kerguelen Plateau: New Perspectives from ODP Leg 120 Sites J. Petrology, July 1, 2002; 43(7): 1207 - 1239. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. INGLE, D. WEIS, and F. A. FREY Indian Continental Crust Recovered from Elan Bank, Kerguelen Plateau (ODP Leg 183, Site 1137) J. Petrology, July 1, 2002; 43(7): 1241 - 1257. [Abstract] [Full Text] [PDF] |
||||

