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... northern Oman, accommodating ∼ 20 mm yr−1 of convergence between Arabia and Eurasia (Reilinger et al. 2006). In contrast to most other parts of the Alpine–Himalaya mountain chain, convergence with Arabia has not yet obliterated the structure of the hanging-wall fore-arc. Many studies have been done ...
... northern Oman, accommodating ∼ 20 mm yr−1 of convergence between Arabia and Eurasia (Reilinger et al. 2006). In contrast to most other parts of the Alpine–Himalaya mountain chain, convergence with Arabia has not yet obliterated the structure of the hanging-wall fore-arc. Many studies have been done ...
Multiscale seismic reflectivity of shallow thermoclines
... The seasonal thermocline, observed in situ with CTD measurements with a depth sampling of 20 cm, indicates a salinity S=35.5 (pss-78) with small variations of ±0.1. The temperature profile (Fig. 1b1) is characterized by a top layer with a constant temperature T0 = 15.3◦ C followed by a sharp decrease ...
... The seasonal thermocline, observed in situ with CTD measurements with a depth sampling of 20 cm, indicates a salinity S=35.5 (pss-78) with small variations of ±0.1. The temperature profile (Fig. 1b1) is characterized by a top layer with a constant temperature T0 = 15.3◦ C followed by a sharp decrease ...
alleghanian plutonism in the eastern blue ridge
... Samson et al. 1995a, Hatcher 2005). With the exception of the EBR plutons - which predate the 330 Ma estimated collision of Laurentia and Gondwana (Hatcher 1989) - the geochronological and geochemical analyses for many of the plutons support crustal melting. In order to determine whether plutonism o ...
... Samson et al. 1995a, Hatcher 2005). With the exception of the EBR plutons - which predate the 330 Ma estimated collision of Laurentia and Gondwana (Hatcher 1989) - the geochronological and geochemical analyses for many of the plutons support crustal melting. In order to determine whether plutonism o ...
Age, Origin and Emplacement of Diamonds
... mineralogic properties of diamonds, the roclzs in which they crystallize, as well as the roclzs that brought them to the surface and in which they now are found as primary deposits. Clearly, such a broad survey is beyond the scope of this article. Therefore, we will focus on those aspects of diamond ...
... mineralogic properties of diamonds, the roclzs in which they crystallize, as well as the roclzs that brought them to the surface and in which they now are found as primary deposits. Clearly, such a broad survey is beyond the scope of this article. Therefore, we will focus on those aspects of diamond ...
workshop report
... It is widely thought that continental crust has been created, or at least recycled, in subduction zones for the last ~3.5 Ga (e.g., Taylor, 1967; Rudnick, 1995). Although it is possible that some or most was originally created by obscure processes in the Hadean (e.g., Armstrong, 1968) and that some ...
... It is widely thought that continental crust has been created, or at least recycled, in subduction zones for the last ~3.5 Ga (e.g., Taylor, 1967; Rudnick, 1995). Although it is possible that some or most was originally created by obscure processes in the Hadean (e.g., Armstrong, 1968) and that some ...
Moho map of South America from receiver functions and surface
... directly before and after the direct P arrival as is seen in the observed RFs because we do not use a high pass filter during the computation of the synthetic RFs. The troughs surrounding the peaks are a result of noise and of filtering and also seen in the results of deconvolving the vertical compo ...
... directly before and after the direct P arrival as is seen in the observed RFs because we do not use a high pass filter during the computation of the synthetic RFs. The troughs surrounding the peaks are a result of noise and of filtering and also seen in the results of deconvolving the vertical compo ...
An enhanced image of the PamirHindu Kush
... studied by Je¡reys 1923). In a historical aside, it is interesting to note that Turner showed that deep-focus earthquakes existed in 1922 and Je¡reys used the 1911 Pamir earthquake, which was a shallow shock, to argue against this possibility in 1923! Gutenberg & Richter (1954) located several earth ...
... studied by Je¡reys 1923). In a historical aside, it is interesting to note that Turner showed that deep-focus earthquakes existed in 1922 and Je¡reys used the 1911 Pamir earthquake, which was a shallow shock, to argue against this possibility in 1923! Gutenberg & Richter (1954) located several earth ...
The Ingalls ophiolite complex, central Cascades, Washington
... with arc formation (Scotia Sea; Larter et al., 2003) or by rifting of a previously active arc (Lau and Mariana Basins; Hawkins, 1995, 2003; Martinez and Taylor, 2003). Rifting within the forearc also occurs in the suprasubduction-zone environment (Bloomer, 1983; Bloomer and Hawkins, 1983; Hawkins an ...
... with arc formation (Scotia Sea; Larter et al., 2003) or by rifting of a previously active arc (Lau and Mariana Basins; Hawkins, 1995, 2003; Martinez and Taylor, 2003). Rifting within the forearc also occurs in the suprasubduction-zone environment (Bloomer, 1983; Bloomer and Hawkins, 1983; Hawkins an ...
Perspectives on the origin of plagiogranite in ophiolites from oxygen
... ridges possibly reflects limited drilling within plutonic crust, or differences in the geodynamic setting in which most ophiolites form. Dilek and Furnes (2011) classify two general categories for ophiolites. Subduction-related ophiolites include suprasubduction-zone and volcanic arc types, whereas s ...
... ridges possibly reflects limited drilling within plutonic crust, or differences in the geodynamic setting in which most ophiolites form. Dilek and Furnes (2011) classify two general categories for ophiolites. Subduction-related ophiolites include suprasubduction-zone and volcanic arc types, whereas s ...
nature and composition of the continental crust
... leaving high-velocity medium at critical angle. A head wave corresponds to a refracted wave that travels along the interface of a velocity discontinuity. Heat-producing elements (HPE): those elements that generate heat as a result of their rapid radioactive decay (i.e., K, Th, and U). Interference: ...
... leaving high-velocity medium at critical angle. A head wave corresponds to a refracted wave that travels along the interface of a velocity discontinuity. Heat-producing elements (HPE): those elements that generate heat as a result of their rapid radioactive decay (i.e., K, Th, and U). Interference: ...
Kimberlites and Lamproites: Primary Sources of Diamond
... chrome pyrope xenocrysts, known colloquially as GI0 garnets, in kimberlites Is commonly regarded as a key indicator for the presence of diamond (see below). The inclusionsof the eclogite suite consist principally of orange pyrope-almandlne, omphacitic pyroxene, kyanite and coesite. The assemblage is ...
... chrome pyrope xenocrysts, known colloquially as GI0 garnets, in kimberlites Is commonly regarded as a key indicator for the presence of diamond (see below). The inclusionsof the eclogite suite consist principally of orange pyrope-almandlne, omphacitic pyroxene, kyanite and coesite. The assemblage is ...
Three-dimensional crustal structure of the Mariana island arc from
... Seismic Studies of the Lithosphere) that were deployed on the volcanic islands, but only two instruments from Tinian and Saipan yielded useful data. After deploying the OBS instruments, the R/V Ewing shot four north – south lines and seven east – west lines plus six short-transit lines using a 20gun ...
... Seismic Studies of the Lithosphere) that were deployed on the volcanic islands, but only two instruments from Tinian and Saipan yielded useful data. After deploying the OBS instruments, the R/V Ewing shot four north – south lines and seven east – west lines plus six short-transit lines using a 20gun ...
Origin and models of oceanic transform faults. Tectonophysics, 522
... first have seismic moment release one-two orders higher; their contribution into the total seismic budget of mid ocean ridges increases with higher spreading rate. The relationships between the seismic moment release, fault length and spreading rate are quite different for transform and rift parts of ...
... first have seismic moment release one-two orders higher; their contribution into the total seismic budget of mid ocean ridges increases with higher spreading rate. The relationships between the seismic moment release, fault length and spreading rate are quite different for transform and rift parts of ...
Formation and stability of magmatic segments in the Main Ethiopian
... segments, in agreement with observations. Renewed magma injections will then preferentially occur in the magmatic segments, promoting the stability of the segmented structure. The patterns predicted by our models are observed in the Ethiopian and Afar rifts, suggesting strong similarities between co ...
... segments, in agreement with observations. Renewed magma injections will then preferentially occur in the magmatic segments, promoting the stability of the segmented structure. The patterns predicted by our models are observed in the Ethiopian and Afar rifts, suggesting strong similarities between co ...
Crustal thickening in Gansu-Qinghai, lithospheric mantle subduction
... length/width ratio, suggesting that they have grown self-similarly. The greatest mountain ranges, which are over 5.5 km high, tens of kilometres wide and hundreds of kilometres long may thus be interpreted to have formed as NW-trending ramp anticlines, at the scale of the middle–upper crust. The fai ...
... length/width ratio, suggesting that they have grown self-similarly. The greatest mountain ranges, which are over 5.5 km high, tens of kilometres wide and hundreds of kilometres long may thus be interpreted to have formed as NW-trending ramp anticlines, at the scale of the middle–upper crust. The fai ...
Earth and Planetary Science
... crustal thickness is about 3–6 km, corresponding to isostatic topography of −0.8 to 0 km. (4) Non-isostatically-compensated topography. We calculated nonisostatic topography (T n-iso ) by removing from the observed bathymetry (Fig. 2) the effects of sediment loading (Fig. 3a), thermal subsidence, an ...
... crustal thickness is about 3–6 km, corresponding to isostatic topography of −0.8 to 0 km. (4) Non-isostatically-compensated topography. We calculated nonisostatic topography (T n-iso ) by removing from the observed bathymetry (Fig. 2) the effects of sediment loading (Fig. 3a), thermal subsidence, an ...
Roberts et al., 2013, Basin Modeling
... factor resulting from the break-up process, together with the post-break-up palaeobathymetric evolution of the margin. It is a simple but powerful technique to employ as the fundamental requirement is simply a 2D or 3D model (cross-section or maps) of the post-break-up margin stratigraphy. •• 2d/3d ...
... factor resulting from the break-up process, together with the post-break-up palaeobathymetric evolution of the margin. It is a simple but powerful technique to employ as the fundamental requirement is simply a 2D or 3D model (cross-section or maps) of the post-break-up margin stratigraphy. •• 2d/3d ...
Geologic Structures
... solid cores behind. The massive outer planets are still composed mostly of hydrogen and helium. ...
... solid cores behind. The massive outer planets are still composed mostly of hydrogen and helium. ...
Physical properties of upper oceanic crust
... exclude the data of Wallick et al. [1992], because of incomplete removal of interstitial water during drying [Jarrard et al., 1995]. Leg 185 basalt physical properties sampling used a much closer sample spacing than at any previous deep crustal site: approximately three samples per core. At each hor ...
... exclude the data of Wallick et al. [1992], because of incomplete removal of interstitial water during drying [Jarrard et al., 1995]. Leg 185 basalt physical properties sampling used a much closer sample spacing than at any previous deep crustal site: approximately three samples per core. At each hor ...
Thematic Article Tethyan ophiolites and Pangea break-up
... crossed the eastern portion of the equatorial Pangea. It is still a matter of debate whether this oceanic basin was a new, developing branch of the Paleotethys Ocean. Alternatively, the basin could have formed as an incipient opening of a new ocean, the Eastern Mesozoic Tethys or ‘Neotethys’, which, ...
... crossed the eastern portion of the equatorial Pangea. It is still a matter of debate whether this oceanic basin was a new, developing branch of the Paleotethys Ocean. Alternatively, the basin could have formed as an incipient opening of a new ocean, the Eastern Mesozoic Tethys or ‘Neotethys’, which, ...
Experimental Constraints on TTG Petrogenesis: Implications
... experimental melting of amphibolites allows a mineralogical model for amphibolite melting to be derived for three different starting lithologies. A major and trace element model for melt compositions is produced using the mineralogical model. This model suggests that TTGs formed at P > 15 kbar and T ...
... experimental melting of amphibolites allows a mineralogical model for amphibolite melting to be derived for three different starting lithologies. A major and trace element model for melt compositions is produced using the mineralogical model. This model suggests that TTGs formed at P > 15 kbar and T ...
the Scanned PDF
... (Wilshire and Binns, 1961). The plagioclaseis probably derived from small amounts of CaSiOa and MgAlzSiO2 originally contained in the bronzite. In such cases,the symplectite showsmore complex texture. Augite forms relatively large anhedral plates up to 2 mm long with graphic intergrowths of spinel. ...
... (Wilshire and Binns, 1961). The plagioclaseis probably derived from small amounts of CaSiOa and MgAlzSiO2 originally contained in the bronzite. In such cases,the symplectite showsmore complex texture. Augite forms relatively large anhedral plates up to 2 mm long with graphic intergrowths of spinel. ...
Continental Growth and Recycling in Convergent Orogens with
... material to the mantle via sediment subduction, subduction erosion, and delamination. Continental growth occurs at plate boundaries and within plates via plumes, and the relative importance between these has changed over time. The record of continental growth remains elusive because orogenic process ...
... material to the mantle via sediment subduction, subduction erosion, and delamination. Continental growth occurs at plate boundaries and within plates via plumes, and the relative importance between these has changed over time. The record of continental growth remains elusive because orogenic process ...
Mantle plume
A mantle plume is a mechanism proposed in 1971 to explain volcanic regions of the earth that were not thought to be explicable by the then-new theory of plate tectonics. Some such volcanic regions lie far from tectonic plate boundaries, for example, Hawaii. Others represent unusually large-volume volcanism, whether on plate boundaries, e.g. Iceland, or basalt floods such as the Deccan or Siberian traps.A mantle plume is posited to exist where hot rock nucleates at the core-mantle boundary and rises through the Earth's mantle becoming a diapir in the Earth's crust. The currently active volcanic centers are known as ""hot spots"". In particular, the concept that mantle plumes are fixed relative to one another, and anchored at the core-mantle boundary, was thought to provide a natural explanation for the time-progressive chains of older volcanoes seen extending out from some such hot spots, such as the Hawaiian–Emperor seamount chain.The hypothesis of mantle plumes from depth is not universally accepted as explaining all such volcanism. It has required progressive hypothesis-elaboration leading to variant propositions such as mini-plumes and pulsing plumes. Another hypothesis for unusual volcanic regions is the ""Plate model"". This proposes shallower, passive leakage of magma from the mantle onto the Earth's surface where extension of the lithosphere permits it, attributing most volcanism to plate tectonic processes, with volcanoes far from plate boundaries resulting from intraplate extension.