The Bent Hawaiian-Emperor Hotspot Track
... plate motion change (17). Both plate circuits paleomagnetic determinations from ocean large volume flux (~350 m3 s−1) (21), spatial pass paleomagnetic consistency tests (14); we drilling (1, 8). pattern, and longevity are best explained by the cannot distinguish between them with the mantle plume hy ...
... plate motion change (17). Both plate circuits paleomagnetic determinations from ocean large volume flux (~350 m3 s−1) (21), spatial pass paleomagnetic consistency tests (14); we drilling (1, 8). pattern, and longevity are best explained by the cannot distinguish between them with the mantle plume hy ...
Large Igneous Provinces, Delamination, and Fertile Mantle
... volume of basalt, the uplift history, and the ubiquitous evidence for involvement of both continental and mid-ocean ridge material in LIP magmas. Some igneous provinces are built on top of rafted pieces of microcontinents or abandoned island arcs, but is there any mechanism for putting large chunks ...
... volume of basalt, the uplift history, and the ubiquitous evidence for involvement of both continental and mid-ocean ridge material in LIP magmas. Some igneous provinces are built on top of rafted pieces of microcontinents or abandoned island arcs, but is there any mechanism for putting large chunks ...
Mesozoic extensional and strike-slip fault systems in magmatic arc
... were empIaced between c. 153 Ma and c. 126 Ma at high levels in the crust - above the regional ductilebrittle transition. This is known because of the concordance of mineral and whole-rock cooling ages obtained for individual plutons by a range of isotope systems (Brown and others, 1991; 1993). Howe ...
... were empIaced between c. 153 Ma and c. 126 Ma at high levels in the crust - above the regional ductilebrittle transition. This is known because of the concordance of mineral and whole-rock cooling ages obtained for individual plutons by a range of isotope systems (Brown and others, 1991; 1993). Howe ...
Modeling evolution of the San Andreas Fault system in northern and
... SAFS is characterized by a relatively complex tectonics. In particular it is influenced by subduction of the Gorda plate to the north of MTJ, and by a large transpressive bend near the Frazier Park in Southern California, the so-called “big bend”. The present day tectonic regime of the San Andreas p ...
... SAFS is characterized by a relatively complex tectonics. In particular it is influenced by subduction of the Gorda plate to the north of MTJ, and by a large transpressive bend near the Frazier Park in Southern California, the so-called “big bend”. The present day tectonic regime of the San Andreas p ...
Plate Tectonics
... Plate Tectonics • Theory that the lithosphere is made up of plates that float on the asthenosphere • Plates possibly moved by ...
... Plate Tectonics • Theory that the lithosphere is made up of plates that float on the asthenosphere • Plates possibly moved by ...
Geological Evidence For The Geographical Pattern of Mantle Return
... trenches and at the Java Trench meet south of Australia, filling in behind this rapidly northwardmoving continent and providingan explanationfor the negativebathymetricand gravity anomalies of the 'Australian-Antarctic Discordance'. The long-continued tectonic movements toward the east that characte ...
... trenches and at the Java Trench meet south of Australia, filling in behind this rapidly northwardmoving continent and providingan explanationfor the negativebathymetricand gravity anomalies of the 'Australian-Antarctic Discordance'. The long-continued tectonic movements toward the east that characte ...
Calculating plate movement and plate motion activity File
... of sea-floor spreading. While the process of plate motion is slow (measured in millimeters per year), this divergence between plates results in the creation of tens of kilometers of new oceanic crust every million years. (Note that 1 mm/year = 1 km/million years.) ...
... of sea-floor spreading. While the process of plate motion is slow (measured in millimeters per year), this divergence between plates results in the creation of tens of kilometers of new oceanic crust every million years. (Note that 1 mm/year = 1 km/million years.) ...
Chapter 7: Plate Tectonics
... East African Rift Valley, a place where Earth’s crust is being pulled apart. If the pulling continues over millions of years, Africa will separate into two landmasses. In this chapter, you’ll learn about rift valleys and other clues that the continents move over time. Science Journal Pretend you’re ...
... East African Rift Valley, a place where Earth’s crust is being pulled apart. If the pulling continues over millions of years, Africa will separate into two landmasses. In this chapter, you’ll learn about rift valleys and other clues that the continents move over time. Science Journal Pretend you’re ...
evidence from Th, Sr and Pb isotope data for Tonga
... to the addition of fluids and/or melts derived from sediments and altered oceanic crust in the subducting slab, to the sub-arc mantle wedge [I -3,321. This model can account for the characteristic enrichment in arc lavas of large-ion lithophile elements (LILE) relative to high field strength element ...
... to the addition of fluids and/or melts derived from sediments and altered oceanic crust in the subducting slab, to the sub-arc mantle wedge [I -3,321. This model can account for the characteristic enrichment in arc lavas of large-ion lithophile elements (LILE) relative to high field strength element ...
large igneous provinces and fertile mantle
... seismic velocities and melting point compared to normal mantle peridotite. Although delaminated continental crust enters the mantle at much lower rates than oceanic crust, the rates are comparable to LIP production volumes. I speculate that the large melting anomalies that form on or near ridges and ...
... seismic velocities and melting point compared to normal mantle peridotite. Although delaminated continental crust enters the mantle at much lower rates than oceanic crust, the rates are comparable to LIP production volumes. I speculate that the large melting anomalies that form on or near ridges and ...
univERsity oF copEnhAGEn
... 3. Precambrian plate tectonics: lithosphere growth by accretion and subduction Recent LITHOPROBE seismic reflection studies across the Archean Superior Province and western margin of the Canadian Shield (e.g. Clowes et al., 1998; Cook et al, 1999) indicate that plate tectonics operated already in th ...
... 3. Precambrian plate tectonics: lithosphere growth by accretion and subduction Recent LITHOPROBE seismic reflection studies across the Archean Superior Province and western margin of the Canadian Shield (e.g. Clowes et al., 1998; Cook et al, 1999) indicate that plate tectonics operated already in th ...
Seismic low-velocity layer at the top of subducting slabs
... Layered structure persists at the tops of subducting plates to depths in excess of 150 km. A low-velocity channel several km thick produces guided seismic guided waves, which indicate that the top of the downgoing plate remains coherent and probably has not eclogitized to >150 km depth. The surround ...
... Layered structure persists at the tops of subducting plates to depths in excess of 150 km. A low-velocity channel several km thick produces guided seismic guided waves, which indicate that the top of the downgoing plate remains coherent and probably has not eclogitized to >150 km depth. The surround ...
Asymmetric ocean basins - Dipartimento di Scienze della Terra
... (Doglioni et al., 2007); in our research we tested whether a worldwide asymmetry holds for oceanic rifts as well. For this purpose, we extracted sections across the S-wave tomographic model of the Earth’s lithosphere-asthenosphere system (Shapiro and Ritzwoller, 2002). The sections are perpendicular ...
... (Doglioni et al., 2007); in our research we tested whether a worldwide asymmetry holds for oceanic rifts as well. For this purpose, we extracted sections across the S-wave tomographic model of the Earth’s lithosphere-asthenosphere system (Shapiro and Ritzwoller, 2002). The sections are perpendicular ...
and island arcs
... • CVZ - Precambrian metamorphic crust, 50-75 km thick • SVZ - Accreted Mesozoic and Cenozoic oceanic crust and island arcs,, 30-45 km thick These are separated by inactive gaps. This belt of igneous rocks developed over last 500 Ma and is commonly termed an Andeantype margin. Image source: Winter, 2 ...
... • CVZ - Precambrian metamorphic crust, 50-75 km thick • SVZ - Accreted Mesozoic and Cenozoic oceanic crust and island arcs,, 30-45 km thick These are separated by inactive gaps. This belt of igneous rocks developed over last 500 Ma and is commonly termed an Andeantype margin. Image source: Winter, 2 ...
Large Igneous Provinces, Delamination, and Fertile Mantle
... volume of basalt, the uplift history, and the ubiquitous evidence for involvement of both continental and mid-ocean ridge material in LIP magmas. Some igneous provinces are built on top of rafted pieces of microcontinents or abandoned island arcs, but is there any mechanism for putting large chunks ...
... volume of basalt, the uplift history, and the ubiquitous evidence for involvement of both continental and mid-ocean ridge material in LIP magmas. Some igneous provinces are built on top of rafted pieces of microcontinents or abandoned island arcs, but is there any mechanism for putting large chunks ...
Geodynamic processes and biochemical interactions at seafloor
... Sclater decided to investigate the arguments—raised by Russian publications— that the apparent equality of heat flow between oceans and continents presented a serious problem to the overall theory of plate tectonics. In contrast, they were able to show that the existing heat flow data and the subsid ...
... Sclater decided to investigate the arguments—raised by Russian publications— that the apparent equality of heat flow between oceans and continents presented a serious problem to the overall theory of plate tectonics. In contrast, they were able to show that the existing heat flow data and the subsid ...
How large is the subducted water flux? New constraints on mantle
... lithosphere with average 10% serpentinization has a density of 3.15 g/cm 3 (Schmidt and Poli, 1998); beyond this degree of serpentinization, slab descent becomes problematic. Alternately, Li and Lee (2006) use an approximation of the spatial distribution of faults and fractures in oceanic lithospher ...
... lithosphere with average 10% serpentinization has a density of 3.15 g/cm 3 (Schmidt and Poli, 1998); beyond this degree of serpentinization, slab descent becomes problematic. Alternately, Li and Lee (2006) use an approximation of the spatial distribution of faults and fractures in oceanic lithospher ...
Asymmetric ocean basins - Indico
... Dipartimento di Scienze della Terra, Università di Trieste, 34127 Trieste, and ICTP Trieste ...
... Dipartimento di Scienze della Terra, Università di Trieste, 34127 Trieste, and ICTP Trieste ...
Parai and Mukhopadhyay 2012
... lithosphere with average 10% serpentinization has a density of 3.15 g/cm 3 (Schmidt and Poli, 1998); beyond this degree of serpentinization, slab descent becomes problematic. Alternately, Li and Lee (2006) use an approximation of the spatial distribution of faults and fractures in oceanic lithospher ...
... lithosphere with average 10% serpentinization has a density of 3.15 g/cm 3 (Schmidt and Poli, 1998); beyond this degree of serpentinization, slab descent becomes problematic. Alternately, Li and Lee (2006) use an approximation of the spatial distribution of faults and fractures in oceanic lithospher ...
Plate Tectonics
... Actually, other factors, such as mantle composition, fertility, focusing of upwelling magmas, volatile content, prior history of the area and lithospheric architecture and stress are important in determining the volume of magma produced at the surface. These are all familiar concepts in geology and ...
... Actually, other factors, such as mantle composition, fertility, focusing of upwelling magmas, volatile content, prior history of the area and lithospheric architecture and stress are important in determining the volume of magma produced at the surface. These are all familiar concepts in geology and ...
Experiments With Portable Ocean Bottom - OBSIP
... To provide answers to some of the outstanding scientific questions related to subduction zone processes, additional ocean bottom seismometers are needed to expand the scope of offshore deployments. Most of the studies to date have been individual lines of instruments. This deployment strategy has do ...
... To provide answers to some of the outstanding scientific questions related to subduction zone processes, additional ocean bottom seismometers are needed to expand the scope of offshore deployments. Most of the studies to date have been individual lines of instruments. This deployment strategy has do ...
Subduction tectonic erosion and Late Cretaceous subsidence along
... The Late Cretaceous to Early Tertiary subsidence history of the Northern Calcareous Alps (NCA) records the effect of two independent basin formation mechanisms at the northern leading margin of the Austroalpine unit. The terrestrial to shallow-marine sediments of the Lower Gosau Subgroup were deposi ...
... The Late Cretaceous to Early Tertiary subsidence history of the Northern Calcareous Alps (NCA) records the effect of two independent basin formation mechanisms at the northern leading margin of the Austroalpine unit. The terrestrial to shallow-marine sediments of the Lower Gosau Subgroup were deposi ...
Can progressive melt extraction from a plum
... been depleted in incompatible elements (Polve and Allegre, 1980). We propose that the mantle experiences progressive melt-extraction as flows upward and melts first deep beneath a hotspot, later more shallowly beneath a mid-ocean ridge. During the first stage, plume upwelling and melting creates an ...
... been depleted in incompatible elements (Polve and Allegre, 1980). We propose that the mantle experiences progressive melt-extraction as flows upward and melts first deep beneath a hotspot, later more shallowly beneath a mid-ocean ridge. During the first stage, plume upwelling and melting creates an ...
Initiation of plate boundary slip in the Nankai Trough off the Muroto
... The difference between porosity patterns of two sites indicates the development of the décollement zone from Site 1174 to Site 808 [Screaton et al., 2002]. [13] We infer that the décollement between the two ODP sites developed following release of shear stress through slip along the décollement a ...
... The difference between porosity patterns of two sites indicates the development of the décollement zone from Site 1174 to Site 808 [Screaton et al., 2002]. [13] We infer that the décollement between the two ODP sites developed following release of shear stress through slip along the décollement a ...
Geology - Geostud
... adjusted from the velocity model used for the ray tracing; the eastward-dipping high-velocity slab, rooted under a zone with a Vp of 7.4 km/s, is added. The RF data require lower velocities in the uppermost crust as well as some local adjustments of Moho depths. A section through 73°N is shown in Fi ...
... adjusted from the velocity model used for the ray tracing; the eastward-dipping high-velocity slab, rooted under a zone with a Vp of 7.4 km/s, is added. The RF data require lower velocities in the uppermost crust as well as some local adjustments of Moho depths. A section through 73°N is shown in Fi ...
Oceanic trench
The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor. Oceanic trenches are a distinctive morphological feature of convergent plate boundaries, along which lithospheric plates move towards each other at rates that vary from a few mm to over ten cm per year. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to a volcanic island arc, and about 200 km (120 mi) from a volcanic arc. Oceanic trenches typically extend 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic floor. The greatest ocean depth to be sounded is in the Challenger Deep of the Mariana Trench, at a depth of 11,034 m (36,201 ft) below sea level. Oceanic lithosphere moves into trenches at a global rate of about 3 km2/yr.