Tectonics and magmatism of intraplate oceanic rises and the hot spot hypothesis

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doi: 10.1134/S0016852108010068
Author(s): Artamonov, A. V.; Zolotarev, B. P.
Author Affiliation(s): Primary:
Russian Academy of Sciences, Geological Institute, Moscow, Russian Federation
Volume Title: Geotectonics
Source: Geotectonics, 42(1), p.64-79. Publisher: MAIK Nauka/Interperiodica Publishing, Birmingham, AL, United States. ISSN: 0016-8521 CODEN: GEOTBK
Note: In English. 88 refs.; sketch maps
Summary: The brief characteristics of the large intraplate rises of the Indian and Atlantic oceans--the Ninetyeast, Mascarene, Maldives, and Walvis ridges and the Kerguelen Plateau-are discussed. The formation of these, as well as many other intraplate ridges, plateaus, and islands, is usually thought to be a result of the function of long-lived stationary deep-sourced mantle plumes. Despite the wide popularity of this conjecture, many new geological, geophysical, and geochemical data appear to be inconsistent with its basic principles. The rises discussed in this paper are characterized by some common features in combination with peculiarities in magmatism, which are explained in terms of the hot-spot hypothesis by different-scale interaction between the plume material and the depleted upper mantle source. Such an approach provides no convincing evidence that explains the block structure of rises, compositional variations in basalts of their basements, etc. The formation of large fault zones in the consolidated oceanic crust, which, having reached a certain depth, provoke melting and ascent of the upper mantle material, is regarded as an alternative mechanism responsible for the formation of such structural elements. Deep-sourced and/or asthenospheric fluid flows may substantially affect the melting. A compositional difference in basalts from separate segments of rises is probably due to vertical and lateral heterogeneity of the upper mantle.
Year of Publication: 2008
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 05 Petrology, Igneous and Metamorphic; 18 Geophysics, Solid-Earth; Atlantic Ocean; Basalts; Continental rise; Crust; Deep Sea Drilling Project; Fault zones; Faults; Fracture zones; Geochemistry; Heterogeneity; Hot spots; IPOD; Igneous rocks; Indian Ocean; Indian Ocean Islands; Indian Plate; Intraplate processes; Kerguelen Plateau; Leg 115; Leg 74; Magmatism; Maldive Islands; Mantle; Mantle plumes; Mascarene Islands; Mid-ocean ridge basalts; Mid-ocean ridges; Ninetyeast Ridge; ODP Site 706; ODP Site 707; Ocean Drilling Program; Ocean floors; Oceanic crust; Petrology; Plate tectonics; South Atlantic; Tectonics; Tholeiitic composition; Volcanic rocks; Walvis Ridge
Coordinates: S073244 S073243 E0590101 E0590100
S130652 S130650 E0612216 E0612215
Record ID: 2009082775
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