Results 181 to 190 of about 4,534 (235)
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The oceanic crust as a bioreactor
2004Various lines of evidence suggest that large portions of hydrothermal systems in the oceanic crust acts like a giant bioreactor that mediates water-rock exchange and buffers the chemical composition of seawater. We review the current literature and present new chemical, biological and petrographic data on microbially mediated alteration of glass in the
Hubert Staudigel +6 more
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AAPG Bulletin, 1979
The model presented is based on the interpretation of marine geophysical data, studies of dredged rocks, theoretical modeling, geologic investigations of ophiolite complexes on the continents, and results of deep-sea crustal drilling by JOIDES/IPOD. Along the axis of the midoceanic ridge system a zone of upwelling asthenosphere extends from the base of
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The model presented is based on the interpretation of marine geophysical data, studies of dredged rocks, theoretical modeling, geologic investigations of ophiolite complexes on the continents, and results of deep-sea crustal drilling by JOIDES/IPOD. Along the axis of the midoceanic ridge system a zone of upwelling asthenosphere extends from the base of
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1993
The mantle contains 84% of the volume and 68% of the mass of the Earth, but because it is separated from direct observation by the thin crust — only about 6 km thick beneath the oceans and an average of 35 km beneath the continental surface — there are many unsolved problems.
G. C. Brown, A. E. Mussett
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The mantle contains 84% of the volume and 68% of the mass of the Earth, but because it is separated from direct observation by the thin crust — only about 6 km thick beneath the oceans and an average of 35 km beneath the continental surface — there are many unsolved problems.
G. C. Brown, A. E. Mussett
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Evidence for Crust in the Deep Ocean derived from Continental Crust
Nature, 1971FIG. 1 shows the profile of a free-air gravity anomaly obtained by HMS Hecate in the Bay of Biscay in 1967 (with two gravi-meters back-to-back to eliminate cross-coupling error). The track is shown in Fig. 2 together with the available deep-water refraction stations; D12 was shot by Ewing and Ewing1 and A by RRS Discovery in 1968 (R. B.
M, Bacon, F, Gray
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1991
In this chapter studies on Indian Ocean abyssal basalts are used as a vehicle to discuss magmatic lineages and melting processes, largely derived from detailed petrographic observations and mineral chemistry. The mineralogical aspects and the magmatic processes envisaged can be considered as adjunct topics to Chapters 5 and 7, respectively, in Part II.
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In this chapter studies on Indian Ocean abyssal basalts are used as a vehicle to discuss magmatic lineages and melting processes, largely derived from detailed petrographic observations and mineral chemistry. The mineralogical aspects and the magmatic processes envisaged can be considered as adjunct topics to Chapters 5 and 7, respectively, in Part II.
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2014
Magma generated by decompression melting of the upwelling mantle beneath mid-ocean ridges (MORs) rises buoyantly and accumulates in crustal magma chambers (e.g., Forsyth, 1992). The long-held view is that oceanic crust is built from in situ crystallization of melts in these reservoirs, as well as from melts extracted from the magma chamber(s) in the ...
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Magma generated by decompression melting of the upwelling mantle beneath mid-ocean ridges (MORs) rises buoyantly and accumulates in crustal magma chambers (e.g., Forsyth, 1992). The long-held view is that oceanic crust is built from in situ crystallization of melts in these reservoirs, as well as from melts extracted from the magma chamber(s) in the ...
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Magnetization of the oceanic crust
Reviews of Geophysics, 1979The Vine‐Matthews [1963] model of the magnetic structure of the igneous oceanic crust, in which basement is considered to be made up of alternating normal and reverse magnetic polarity blocks with a one‐to‐one match with linear marine magnetic anomalies, has received wide acceptance in the geological and geophysical community. Comparison of the results
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1989
Significant differences between ophiolites (table 8.1) led us to distinguish a harzburgite ophiolite type (HOT) and a lherzolite ophiolite type (LOT) which were ascribed respectively to fast and slow spreading situations (chapter 8). Similarly, significant differences between fast and slow spreading ridges encourage comparisons with these two types of ...
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Significant differences between ophiolites (table 8.1) led us to distinguish a harzburgite ophiolite type (HOT) and a lherzolite ophiolite type (LOT) which were ascribed respectively to fast and slow spreading situations (chapter 8). Similarly, significant differences between fast and slow spreading ridges encourage comparisons with these two types of ...
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1988
The Nd isotopic data provide an important addition to petrogenetic modeling studies of igneous rocks because they provide previously unavailable information about the chemical composition of magma sources. Oceanic basalts present the possibility of applying the isotopic data for this purpose in a relatively straightforward way because there is little ...
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The Nd isotopic data provide an important addition to petrogenetic modeling studies of igneous rocks because they provide previously unavailable information about the chemical composition of magma sources. Oceanic basalts present the possibility of applying the isotopic data for this purpose in a relatively straightforward way because there is little ...
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New Model for the Structure of the Ocean Crust
Nature, 1970USING the ocean floor spreading/plate tectonics theory as a starting point, examining the implications of this theory for processes taking place at mid-ocean ridge crests, and adding data collected from dredged rocks and geophysical measurements in the oceans, it is possible to build up a well controlled model of the structure of the ocean crust and ...
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