riDge-HotSpot iNteractioNS what mid-ocean ridges tell us
... debate in the scientific community. The “plume” model hypothesizes rising of buoyant mantle plumes as the primary cause of prominent hotspots such as Iceland and Hawaii (Morgan, 1971). In contrast, the “anti-plume” school argues that many of the observed “hotspot” volcanic and geochemical anomalies ...
... debate in the scientific community. The “plume” model hypothesizes rising of buoyant mantle plumes as the primary cause of prominent hotspots such as Iceland and Hawaii (Morgan, 1971). In contrast, the “anti-plume” school argues that many of the observed “hotspot” volcanic and geochemical anomalies ...
Partial delamination of continental mantle lithosphere, uplift
... deposition rates of coarse sediments supplied into the foreland basin from the eroding orogen (Artyushkov et al., 1996; Sanders, 1998). As a consequence of uplift and associated exhumation, the vertical stress became the maximum compressive stress in rock formations approaching the surface, whilst t ...
... deposition rates of coarse sediments supplied into the foreland basin from the eroding orogen (Artyushkov et al., 1996; Sanders, 1998). As a consequence of uplift and associated exhumation, the vertical stress became the maximum compressive stress in rock formations approaching the surface, whilst t ...
Anderson and Natland, 2005
... Plate tectonics was developed during the 1960s and 1970s as a kinematic and descriptive theory that involved such idealizations as rigid (or elastic) and permanent plates, sharp plate boundaries, uniform isothermal mantle, homogeneous plates, and steady-state conditions. Diffuse plate boundaries, vo ...
... Plate tectonics was developed during the 1960s and 1970s as a kinematic and descriptive theory that involved such idealizations as rigid (or elastic) and permanent plates, sharp plate boundaries, uniform isothermal mantle, homogeneous plates, and steady-state conditions. Diffuse plate boundaries, vo ...
Thermal evolution of the Earth as recorded by komatiites
... a Phanerozoic occurrence in Vietnam [14], and the new compositionally distinct 3.3 Ga komatiites from the Commondale Belt, South Africa [15,16]. Komatiites are distinguished as ultrama¢c volcanic rocks containing spinifex olivine textures with MgO contents s 18 wt% (Fig. 1). The maximum MgO content ...
... a Phanerozoic occurrence in Vietnam [14], and the new compositionally distinct 3.3 Ga komatiites from the Commondale Belt, South Africa [15,16]. Komatiites are distinguished as ultrama¢c volcanic rocks containing spinifex olivine textures with MgO contents s 18 wt% (Fig. 1). The maximum MgO content ...
Zoned mantle convection
... units as diverse as the depleted upper mantle, the continental crust and the altered oceanic crust. Geochemists observe the outcome of these processes, that is the isotopic heterogeneities, and use either empirical or statistical methods (All³egre et al. 1987; Hart et al . 1992; White 1985; Zindler ...
... units as diverse as the depleted upper mantle, the continental crust and the altered oceanic crust. Geochemists observe the outcome of these processes, that is the isotopic heterogeneities, and use either empirical or statistical methods (All³egre et al. 1987; Hart et al . 1992; White 1985; Zindler ...
The evolving nature of terrestrial crust from the Hadean, through the
... The defining feature of the Archaean mantle could have been a barrier layer in the transition zone. Hot Archaean mantle upwellings originated at the base of the barrier, which acted as a thermal boundary layer. The disappearance of this mechanical barrier in the mantle transition zone could have mark ...
... The defining feature of the Archaean mantle could have been a barrier layer in the transition zone. Hot Archaean mantle upwellings originated at the base of the barrier, which acted as a thermal boundary layer. The disappearance of this mechanical barrier in the mantle transition zone could have mark ...
Weathering
... slabs called plates. Forces deep within Earth cause these plates to move and change the surface. For example, most mountains form when plates come together. ...
... slabs called plates. Forces deep within Earth cause these plates to move and change the surface. For example, most mountains form when plates come together. ...
mid-ocean ridges: mantle convection
... Figure 2 (a) Global average (dots) seafloor depth (after correcting for sedimentation) and standard deviations (light curve) increase with seafloor age. Dashed curve is predicted by assuming that the lithosphere cools and thickens indefinitely, as if it overlies an infinite half space. Solid curve a ...
... Figure 2 (a) Global average (dots) seafloor depth (after correcting for sedimentation) and standard deviations (light curve) increase with seafloor age. Dashed curve is predicted by assuming that the lithosphere cools and thickens indefinitely, as if it overlies an infinite half space. Solid curve a ...
“The “plate” model for the genesis of melting anomalies”
... 1990). Such basalts are called “ocean-island basalts” (OIB). Because it was assumed that “hotspots” are fueled by plumes from the deep mantle, their geochemical characteristics were thought to reveal lower mantle characteristics. The numbers of postulated “hotspots” and plumes rose to approximately ...
... 1990). Such basalts are called “ocean-island basalts” (OIB). Because it was assumed that “hotspots” are fueled by plumes from the deep mantle, their geochemical characteristics were thought to reveal lower mantle characteristics. The numbers of postulated “hotspots” and plumes rose to approximately ...
Text
... Understanding how the Earth’s first continental land masses were generated is important because the processes responsible directly affected the evolution of the planet’s primordial silicate interior, and also its atmosphere and hydrosphere. Archaean continental crust is dominated by rocks of the tro ...
... Understanding how the Earth’s first continental land masses were generated is important because the processes responsible directly affected the evolution of the planet’s primordial silicate interior, and also its atmosphere and hydrosphere. Archaean continental crust is dominated by rocks of the tro ...
Antipodal hotspots and bipolar catastrophes: Were oceanic large
... between 40 and 50, meeting a larger number of specific criteria. These generally include a long-lived track, initial flood basalt eruptions, a high buoyancy flux, high 3He/4He ratios, and anomalously low shear velocities in the underlying mantle. Only 9 out of 49 hotspots on Courtillot et al.’s list ...
... between 40 and 50, meeting a larger number of specific criteria. These generally include a long-lived track, initial flood basalt eruptions, a high buoyancy flux, high 3He/4He ratios, and anomalously low shear velocities in the underlying mantle. Only 9 out of 49 hotspots on Courtillot et al.’s list ...
Towards a Creationist Explanation of Regional
... identical to the “classical” zones of regional metamorphism, and yet minerals are together in the same assemblage that would normally be regarded as having formed under vastly different temperature and pressure conditions. Thus it is shown that these metamorphic minerals have been primarily formed f ...
... identical to the “classical” zones of regional metamorphism, and yet minerals are together in the same assemblage that would normally be regarded as having formed under vastly different temperature and pressure conditions. Thus it is shown that these metamorphic minerals have been primarily formed f ...
Chapter 21: Metamorphism
... The IUGS-SCMR proposed this definition: Metamorphism is a subsolidus process leading to changes in mineralogy and/or texture (for example grain size) and often in chemical composition in a rock. These changes are due to physical and/or chemical conditions that differ from those normally occurring at ...
... The IUGS-SCMR proposed this definition: Metamorphism is a subsolidus process leading to changes in mineralogy and/or texture (for example grain size) and often in chemical composition in a rock. These changes are due to physical and/or chemical conditions that differ from those normally occurring at ...
Review of the Lithium Isotope System as a Geochemical Tracer
... weathering (Huh et al., 1998). There is thus promise in using the evolution of the Li isotope ratio of seawater to assess past changes in the intensity of continental weathering (Raymo et al., 1988). In other words, it might be anticipated that a change to lighter Li isotopic compositions in ancient ...
... weathering (Huh et al., 1998). There is thus promise in using the evolution of the Li isotope ratio of seawater to assess past changes in the intensity of continental weathering (Raymo et al., 1988). In other words, it might be anticipated that a change to lighter Li isotopic compositions in ancient ...
Plume heads, continental lithosphere, flood
... discontinuous LVZ extending NW from ·Ber- may be chemically distinct as well. It may, for muda to Iceland and Jan Mayan, This may be example, be the depleted reservoir and not well due to the continental edge effect, discussed by mixed with the shallow mantle. Much of the Vogt (1991) . He pointed ou ...
... discontinuous LVZ extending NW from ·Ber- may be chemically distinct as well. It may, for muda to Iceland and Jan Mayan, This may be example, be the depleted reservoir and not well due to the continental edge effect, discussed by mixed with the shallow mantle. Much of the Vogt (1991) . He pointed ou ...
Chapter 21: Metamorphism
... Cpx + plag ( olivine, ilmenite…) Or any combination of melt + minerals along the liquid line of descent If uplifted and eroded surface, will weather a combinations of clays, oxides… ...
... Cpx + plag ( olivine, ilmenite…) Or any combination of melt + minerals along the liquid line of descent If uplifted and eroded surface, will weather a combinations of clays, oxides… ...
Earth Science Ch. 6 Practice Test
... Identify the choice that best completes the statement or answers the question. ____ 1. Volcanic belts form along a. islands in the Pacific Ocean. b. North American mountain ranges. c. the boundaries of Earth’s plates. d. the coast of Antarctica. ____ 2. Before lava reaches the surface, the molten ma ...
... Identify the choice that best completes the statement or answers the question. ____ 1. Volcanic belts form along a. islands in the Pacific Ocean. b. North American mountain ranges. c. the boundaries of Earth’s plates. d. the coast of Antarctica. ____ 2. Before lava reaches the surface, the molten ma ...
Large igneous provinces linked to supercontinent assembly
... There are several reasons why the Tarim and Emeishan LIPs are probably not related to the postulated two mantle plumes. First, there are no radiating dyke swarms, and no features typical of mantle head and tail magmatism in the LIP that Zhang et al. (2006) advocated. Second, previous reports of a 1- ...
... There are several reasons why the Tarim and Emeishan LIPs are probably not related to the postulated two mantle plumes. First, there are no radiating dyke swarms, and no features typical of mantle head and tail magmatism in the LIP that Zhang et al. (2006) advocated. Second, previous reports of a 1- ...
Inclusions in Sublithospheric Diamonds
... mantle minerals. Based on these data, the mantle is subdivided into three major layers (see FIGS. 1 AND 2): ...
... mantle minerals. Based on these data, the mantle is subdivided into three major layers (see FIGS. 1 AND 2): ...
The heavy noble gas composition of the depleted MORB mantle
... sources of the Iceland plume and the gas-rich MORB (‘‘popping rock’’) from the north Atlantic (Kunz et al., 1998; Moreira et al., 1998) cannot be related solely through recycling of atmospheric noble gases; differences in the degree of mantle degassing are required to explain the observed Ar and Xe ...
... sources of the Iceland plume and the gas-rich MORB (‘‘popping rock’’) from the north Atlantic (Kunz et al., 1998; Moreira et al., 1998) cannot be related solely through recycling of atmospheric noble gases; differences in the degree of mantle degassing are required to explain the observed Ar and Xe ...
Accuracy of plagioclase compositions from laboratory and Mars
... 2.1.2. Petrography and Modal Mineralogy [10] All samples except 79-35i have porphyritic textures with variable amounts of euhedral to subhedral plagioclase, pyroxene, olivine, and amphibole phenocrysts. Dacites contain potassium feldspar, amphibole, and quartz phenocrysts. Plagioclase and pyroxene p ...
... 2.1.2. Petrography and Modal Mineralogy [10] All samples except 79-35i have porphyritic textures with variable amounts of euhedral to subhedral plagioclase, pyroxene, olivine, and amphibole phenocrysts. Dacites contain potassium feldspar, amphibole, and quartz phenocrysts. Plagioclase and pyroxene p ...
Setting Based Classification
... intruding cooler shallow rocks • Occur over a wide range of pressures, including very low • Contact aureole ...
... intruding cooler shallow rocks • Occur over a wide range of pressures, including very low • Contact aureole ...
Shervais, J.W., Significance of Subduction
... of this debate hinges on the stratigraphy of Archean greenstone belts, their internal structure, and their relationship to the surrounding TTG gneisses. The oldest intact rock sequences on Earth have been dated at around 3.6-4.03 Ga (DeRonde et al., 1994; Nutman et al., 1993, 1997, 2004; Kusky, 199 ...
... of this debate hinges on the stratigraphy of Archean greenstone belts, their internal structure, and their relationship to the surrounding TTG gneisses. The oldest intact rock sequences on Earth have been dated at around 3.6-4.03 Ga (DeRonde et al., 1994; Nutman et al., 1993, 1997, 2004; Kusky, 199 ...
Relationship between Moldanubicum, the Kutn· Hora Crystalline
... share some common features, rocks of GU and Bohemicum differ significantly and originated in separate basins and tectonic settings. Paragneisses of MSZ and MVG show evolved REE patterns as well as enrichment in K2O, P2O5, Rb, Ba, Th and depletion in CaO, Na2O nad Sr compared to the average upper con ...
... share some common features, rocks of GU and Bohemicum differ significantly and originated in separate basins and tectonic settings. Paragneisses of MSZ and MVG show evolved REE patterns as well as enrichment in K2O, P2O5, Rb, Ba, Th and depletion in CaO, Na2O nad Sr compared to the average upper con ...
Basalt
Basalt (pronounced /bəˈsɔːlt/, /ˈbæsɒlt/, /ˈbæsɔːlt/, or /ˈbeɪsɔːlt/)is a common extrusive igneous (volcanic) rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. Flood basalt describes the formation in a series of lava basalt flows.