Deep seismic reflection profiling of Archean cratons
... • By analogy with modern examples, mantle reflections are often interpreted as indicators of ...
... • By analogy with modern examples, mantle reflections are often interpreted as indicators of ...
Developing the plate tectonics from oceanic subduction to
... upper mantle, and the nature and diversity of mantle-derived magmas. On one hand, these new discoveries and scientific insights are rooted in the study of mineralogy and petrology[15,16]. On the other hand, prominent progresses have been also made by dynamic interpretations of isotope geochronologic ...
... upper mantle, and the nature and diversity of mantle-derived magmas. On one hand, these new discoveries and scientific insights are rooted in the study of mineralogy and petrology[15,16]. On the other hand, prominent progresses have been also made by dynamic interpretations of isotope geochronologic ...
Episodic crustal growth and mantle evolution
... intermittent. This interpretation is certainly controversial, and it may be that the 'quiescent' periods merely represent missing continental material, which has been recycled back into the mantle. However, Reymer and Schubert (1984, 1986) have shown that crust formation rates during some geological ...
... intermittent. This interpretation is certainly controversial, and it may be that the 'quiescent' periods merely represent missing continental material, which has been recycled back into the mantle. However, Reymer and Schubert (1984, 1986) have shown that crust formation rates during some geological ...
Growth and mixing dynamics of mantle wedge plumes
... results with an exposed ultramafic complex, the Horoman Complex, located in Japan. We have performed high-resolution twodimensional experiments containing 10 × 109 randomly distributed markers using the new parallel code I2OMP developed from the I2VIS (Gerya and Yuen, 2003a). Effective resolution (2 ...
... results with an exposed ultramafic complex, the Horoman Complex, located in Japan. We have performed high-resolution twodimensional experiments containing 10 × 109 randomly distributed markers using the new parallel code I2OMP developed from the I2VIS (Gerya and Yuen, 2003a). Effective resolution (2 ...
Lecture 38
... (1) all refractory elements during condensation and (2) are not siderophiles, and (3) because the core is about a third of the mass of the Earth, estimated primitive-mantle REE concentrations are all about three times the C1 chondritic average values. ...
... (1) all refractory elements during condensation and (2) are not siderophiles, and (3) because the core is about a third of the mass of the Earth, estimated primitive-mantle REE concentrations are all about three times the C1 chondritic average values. ...
TECHNICAL REVIEW OF GEOTHERMAL
... crater lake from below, with temperatures of up to 89 C and a flow rate of 44 ± 7 L/s. This corresponds to a maximum natural heat discharge of 16 ± 3 MW (thermal). The neutral chloride upflow into the Ngozi crater lake is able to overcome the pressure of the lake surface at 2074 m asl, which is muc ...
... crater lake from below, with temperatures of up to 89 C and a flow rate of 44 ± 7 L/s. This corresponds to a maximum natural heat discharge of 16 ± 3 MW (thermal). The neutral chloride upflow into the Ngozi crater lake is able to overcome the pressure of the lake surface at 2074 m asl, which is muc ...
Subduction-zone metamorphism, calc-alkaline - U
... to significant differences in regional metamorphic phase assemblages, described contrasting geologic occurrences, and inferred their characteristic ranges of physical conditions. He advanced the paired metamorphic belt concept, involving an oceanward, narrow, high-P/low-T blueschist zone intimately i ...
... to significant differences in regional metamorphic phase assemblages, described contrasting geologic occurrences, and inferred their characteristic ranges of physical conditions. He advanced the paired metamorphic belt concept, involving an oceanward, narrow, high-P/low-T blueschist zone intimately i ...
OMAN: an obduction
... The crust/mantle transition zone (Moho) is few meters to few hundred meters thick. Gabbro lenses are imbedded in dunite, plagioclase and clinopyroxene-impregnated dunite, and depleted harzburgite. The gabbro content increases upwards at the expenses of other rock types. Note: Since the crust/mantle ...
... The crust/mantle transition zone (Moho) is few meters to few hundred meters thick. Gabbro lenses are imbedded in dunite, plagioclase and clinopyroxene-impregnated dunite, and depleted harzburgite. The gabbro content increases upwards at the expenses of other rock types. Note: Since the crust/mantle ...
ManuscriptPDF
... melting, when relatively weak partial melt is produced, leading to an overall weakening of the rock (e.g. Arzi, 1978). A solid-state example of weakening by the replacement of relatively strong minerals by relatively weak minerals occurs during the serpentinization of mafic rocks, when relatively str ...
... melting, when relatively weak partial melt is produced, leading to an overall weakening of the rock (e.g. Arzi, 1978). A solid-state example of weakening by the replacement of relatively strong minerals by relatively weak minerals occurs during the serpentinization of mafic rocks, when relatively str ...
The break-up of continents and the formation of new ocean basins
... to read this record by drilling into the rocks at carefully selected locations, by sampling the seabed in areas where crustal rocks are not covered by thick sediments, and by probing the deeper structure with a variety of geophysical techniques. Alongside these experimental studies, theoretical anal ...
... to read this record by drilling into the rocks at carefully selected locations, by sampling the seabed in areas where crustal rocks are not covered by thick sediments, and by probing the deeper structure with a variety of geophysical techniques. Alongside these experimental studies, theoretical anal ...
Geology of the Cerrillos Area - New Mexico Bureau of Geology
... and gold from one group of deposits and turquoise from another. Most of the turquoise in this area was produced from mines at Turquoise Hill and Mt. Chalchihuitl from prehistoric time to the present. Turquoise occurs as nodules in fracture zones and in narrow veinlets which cut intrusive and volcani ...
... and gold from one group of deposits and turquoise from another. Most of the turquoise in this area was produced from mines at Turquoise Hill and Mt. Chalchihuitl from prehistoric time to the present. Turquoise occurs as nodules in fracture zones and in narrow veinlets which cut intrusive and volcani ...
Chapter Four: Structural Geology
... Observations regarding this fault are also of a different nature and consist solely of submarine topography, seismic activity, continuity with other such faults, and theoretical considerations. The bathymetry of the west coast of the Queen Charlotte Islands is outlined in a reconnaissance manner on ...
... Observations regarding this fault are also of a different nature and consist solely of submarine topography, seismic activity, continuity with other such faults, and theoretical considerations. The bathymetry of the west coast of the Queen Charlotte Islands is outlined in a reconnaissance manner on ...
Metamorphic and Magmatic Consequences of Subduction of Young
... Ma) oceanic lithosphere, with variation in the rate of induced convergence (2, 4 and 5 cm/yr) across a pre-existing rheologically weak fracture zone. A 2D thermo-mechanical numerical model was developed using the I2VIS code based on conservative finite differences and non-diffusive marker-in-cell te ...
... Ma) oceanic lithosphere, with variation in the rate of induced convergence (2, 4 and 5 cm/yr) across a pre-existing rheologically weak fracture zone. A 2D thermo-mechanical numerical model was developed using the I2VIS code based on conservative finite differences and non-diffusive marker-in-cell te ...
Practice Quiz for Ch. 15 Multiple Choice Identify the choice that best
... 31. The thick tectonic plates are composed of the earth's crust and the rigid, outermost part of the mantle (above the asthenosphere), a combination called the ____________________. 32. A major external process is ____________________, which is the physical, chemical, and biological processes that b ...
... 31. The thick tectonic plates are composed of the earth's crust and the rigid, outermost part of the mantle (above the asthenosphere), a combination called the ____________________. 32. A major external process is ____________________, which is the physical, chemical, and biological processes that b ...
Geology
... (Gorczyk et al., 2007) across the bottom of the model. The velocity boundary conditions are free slip at all boundaries except the lower one, which is permeable in both the downward and upward directions (Gorczyk et al., 2007). The model oceanic crust consists of a 2-kmthick basaltic layer, underlai ...
... (Gorczyk et al., 2007) across the bottom of the model. The velocity boundary conditions are free slip at all boundaries except the lower one, which is permeable in both the downward and upward directions (Gorczyk et al., 2007). The model oceanic crust consists of a 2-kmthick basaltic layer, underlai ...
Insights from the Azuero Peninsula, SW Panama
... Maitre et al. (1989). C; Plot of (La/Sm)PMn vs. (Nb/La)PMn. Primitive mantle from McDonough and Sun (1995). Azuero Plateau, Azuero Protoarc group and Azuero Arc group after Buchs et al. (2010). D-F; Primitive mantle-normalized multielement diagrams of the AIB, APAG and AVA (black lines). Primitive m ...
... Maitre et al. (1989). C; Plot of (La/Sm)PMn vs. (Nb/La)PMn. Primitive mantle from McDonough and Sun (1995). Azuero Plateau, Azuero Protoarc group and Azuero Arc group after Buchs et al. (2010). D-F; Primitive mantle-normalized multielement diagrams of the AIB, APAG and AVA (black lines). Primitive m ...
Structural Geology (Geol 305) Semester (071)
... Rods: rodding or grain aggregates of one or more minerals such as quartz, feldspars and mica (it is common in ductile shear zones) Natural strain ellipsoids : long axes of pebbles, boulders, vesicles and reduction spots. Mullions: form at boundaries between differing rock types. Boudinage: consists ...
... Rods: rodding or grain aggregates of one or more minerals such as quartz, feldspars and mica (it is common in ductile shear zones) Natural strain ellipsoids : long axes of pebbles, boulders, vesicles and reduction spots. Mullions: form at boundaries between differing rock types. Boudinage: consists ...
An Alternative EARTH - Geological Society of America
... hotter than now. Plate tectonics began ca. 2.0 Ga when continents could stand above oceans and oceanic lithosphere could cool to subduction-enabling density and thickness. Upper mantle has since become more fertile and new increments of continental crust more mafic as continental crust has been prog ...
... hotter than now. Plate tectonics began ca. 2.0 Ga when continents could stand above oceans and oceanic lithosphere could cool to subduction-enabling density and thickness. Upper mantle has since become more fertile and new increments of continental crust more mafic as continental crust has been prog ...
Why is subduction on the Earth one-sided?
... (Gorczyk et al., 2007) across the bottom of the model. The velocity boundary conditions are free slip at all boundaries except the lower one, which is permeable in both the downward and upward directions (Gorczyk et al., 2007). The model oceanic crust consists of a 2-kmthick basaltic layer, underlai ...
... (Gorczyk et al., 2007) across the bottom of the model. The velocity boundary conditions are free slip at all boundaries except the lower one, which is permeable in both the downward and upward directions (Gorczyk et al., 2007). The model oceanic crust consists of a 2-kmthick basaltic layer, underlai ...
Ch 14 OIB mod 7
... lithophile elements to melts which ended in late fractionation rocks, and which has lost He). • OIBs seem to originate from deeper levels. Major- and trace-element data → the deep source of OIB magmas (both tholeiitic and alkaline) is distinct from that of N-MORB. Trace element and isotopic data rei ...
... lithophile elements to melts which ended in late fractionation rocks, and which has lost He). • OIBs seem to originate from deeper levels. Major- and trace-element data → the deep source of OIB magmas (both tholeiitic and alkaline) is distinct from that of N-MORB. Trace element and isotopic data rei ...
Petrogenesis of the Eocene and Mio–Pliocene alkaline basaltic
... raphy in Table 3). AlVI/AlIV in pyroxenes indicates low pressures of crystallization (Simonetti et al., 1996). A major petrographic difference between the two sequences is the presence in the UBS basalts of rounded quartz xenocrysts (1–3 mm) rimmed by clinopyroxene (b0.5 mm wide), the composition of ...
... raphy in Table 3). AlVI/AlIV in pyroxenes indicates low pressures of crystallization (Simonetti et al., 1996). A major petrographic difference between the two sequences is the presence in the UBS basalts of rounded quartz xenocrysts (1–3 mm) rimmed by clinopyroxene (b0.5 mm wide), the composition of ...
Ophiolites: Figments of Oceanic Lithosphere? Geological Society
... Triassic, largely alkaline, basic volcanism. However, although this evidence is consistent with what is known and expected during the early stages of continental rifting we need not assume that the occurrence of Triassic volcanics necessarily marks the exact margin between continental and new oceani ...
... Triassic, largely alkaline, basic volcanism. However, although this evidence is consistent with what is known and expected during the early stages of continental rifting we need not assume that the occurrence of Triassic volcanics necessarily marks the exact margin between continental and new oceani ...
Indonesia The geology and tectonic evolution of the Bacan region
... Lower Miocene sequences. The Upper Eocene, Lower Miocene and the Saleh Island sequences are similar in all aspects, except age. More dating is needed, although this may prove difficult, since despite examination of > 200 thin sections, only four samples were found to be suitable for biostratigraphic ...
... Lower Miocene sequences. The Upper Eocene, Lower Miocene and the Saleh Island sequences are similar in all aspects, except age. More dating is needed, although this may prove difficult, since despite examination of > 200 thin sections, only four samples were found to be suitable for biostratigraphic ...
Word format
... Folds consist of two sides that have the beds dipping in opposite directions to each other (away from each other in an anticline, and towards each other in a syncline). Each side of the fold is called a _________________. Every fold has 2 fold limbs with one always being shared with the fold right n ...
... Folds consist of two sides that have the beds dipping in opposite directions to each other (away from each other in an anticline, and towards each other in a syncline). Each side of the fold is called a _________________. Every fold has 2 fold limbs with one always being shared with the fold right n ...
Continental subduction and exhumation of high
... slice (unit 3 in Fig. 4d) forms in a similar way. Formation of the fourth slice is part of the same delamination process and widening of the interplate zone or orogen. During delamination all units undergo uplift (exhumation). The average equivalent exhumation rate was obtained to be of about 1 cm/y ...
... slice (unit 3 in Fig. 4d) forms in a similar way. Formation of the fourth slice is part of the same delamination process and widening of the interplate zone or orogen. During delamination all units undergo uplift (exhumation). The average equivalent exhumation rate was obtained to be of about 1 cm/y ...
Composition of Mars
The composition of Mars covers the branch of the geology of Mars that describes the make-up of the planet Mars.