Degree-1 mantle convection and the crustal dichotomy on Mars
... structure that is obviously suggestive of plate tectonics [1] and other tectonic processes, such as magmatic intrusion [14], may alternatively explain the magnetic lineations. On the other hand, if the average crustal thickness is V50 km [1], it is unclear whether mantle convection could result in s ...
... structure that is obviously suggestive of plate tectonics [1] and other tectonic processes, such as magmatic intrusion [14], may alternatively explain the magnetic lineations. On the other hand, if the average crustal thickness is V50 km [1], it is unclear whether mantle convection could result in s ...
782 - Head, J. W., and L. S. Crumpler
... hundreds of kilometers (Fig. 3A). Examination of these linear perhaps related to hot spots, produce broad plateaus several kilometopographic features where they cross near-equatorial high-resolu- ters higher than typical mid-ocean rises and several hundred kilometion altimetry tracks (20, 21) reveal ...
... hundreds of kilometers (Fig. 3A). Examination of these linear perhaps related to hot spots, produce broad plateaus several kilometopographic features where they cross near-equatorial high-resolu- ters higher than typical mid-ocean rises and several hundred kilometion altimetry tracks (20, 21) reveal ...
The role of lower continental crust and lithospheric mantle in the
... (Carboniferous^early Permian). During this time, subduction of the proto-Tethys Ocean between the Gondwanan and Laurussian plates [5] was followed by a continent^continent collision, and by intrusion of calc-alkaline plutonic rocks [6]. The tectonic collapse of the Hercynian belt at the end of the P ...
... (Carboniferous^early Permian). During this time, subduction of the proto-Tethys Ocean between the Gondwanan and Laurussian plates [5] was followed by a continent^continent collision, and by intrusion of calc-alkaline plutonic rocks [6]. The tectonic collapse of the Hercynian belt at the end of the P ...
Stress distribution within subducting slabs and their deformation in
... Seismic tomography results show that the slab behavior in the transition zone is complex (e.g. van der Hilst et al., 1991; Bijwaard et al., 1998). Some slabs (e.g. Marianas) seem to penetrate into the lower mantle quite unhindered, while others flatten out temporarily before subducting deeper into t ...
... Seismic tomography results show that the slab behavior in the transition zone is complex (e.g. van der Hilst et al., 1991; Bijwaard et al., 1998). Some slabs (e.g. Marianas) seem to penetrate into the lower mantle quite unhindered, while others flatten out temporarily before subducting deeper into t ...
Plate tectonics conserves angular momentum
... each other) is taken as strong evidence that large thermally driven “roller” convection cells previously inferred as the driving mechanism in earlier interpretations of continental drift and plate tectonics, have not been active in the Earth’s mantle the past 42 Million years, if ever. This report a ...
... each other) is taken as strong evidence that large thermally driven “roller” convection cells previously inferred as the driving mechanism in earlier interpretations of continental drift and plate tectonics, have not been active in the Earth’s mantle the past 42 Million years, if ever. This report a ...
Chapter 8 Notes-Student Guide
... 11. Elastic rebound is the sudden return of elastically deformed rock to its undeformed shape. Elastic rebound occurs when more stress is applied to rock than the rock can withstand. 12. During elastic rebound, energy is released. Some of this energy travels as seismic waves, which cause an earthqua ...
... 11. Elastic rebound is the sudden return of elastically deformed rock to its undeformed shape. Elastic rebound occurs when more stress is applied to rock than the rock can withstand. 12. During elastic rebound, energy is released. Some of this energy travels as seismic waves, which cause an earthqua ...
as a PDF
... layer is discussed in connection with large igneous provinces and volcanic chains. Partial melting is the expected natural state of the upper mantle and only abnormally high seismic velocities imply absence of melting (slabs, cratons). Plume theoreticians have underestimated the average temperature ...
... layer is discussed in connection with large igneous provinces and volcanic chains. Partial melting is the expected natural state of the upper mantle and only abnormally high seismic velocities imply absence of melting (slabs, cratons). Plume theoreticians have underestimated the average temperature ...
Document
... CHUR = “Chonritic Uniform Reservoir” - typically measured on chondritic meteorites (DePaulo and Wasserburg, 1976a) - If CHUR and samples are measured in the same lab, then regardless of normalization and corrections, one can compare εNd values - also practical way to report very small Nd isotope cha ...
... CHUR = “Chonritic Uniform Reservoir” - typically measured on chondritic meteorites (DePaulo and Wasserburg, 1976a) - If CHUR and samples are measured in the same lab, then regardless of normalization and corrections, one can compare εNd values - also practical way to report very small Nd isotope cha ...
0622932 COVER SHEET FOR PROPOSAL TO THE NATIONAL SCIENCE FOUNDATION NSF 02-011
... an inner city public school in Roxbury, MA, and during graduate school, I have been active in a science outreach program at a primary school in Providence, RI. At Brown, I have been a teaching assistant for two courses and have thoroughly enjoyed my teaching experience to date. I would like to conti ...
... an inner city public school in Roxbury, MA, and during graduate school, I have been active in a science outreach program at a primary school in Providence, RI. At Brown, I have been a teaching assistant for two courses and have thoroughly enjoyed my teaching experience to date. I would like to conti ...
Mantle plumes: Why the current skepticism?
... account for conflicting observations, relatively little has been done on developing alternative models, which have as a consequence, mostly remained qualitative only. Quantification of these theories is a new and rapidly developing subject. Models include: ...
... account for conflicting observations, relatively little has been done on developing alternative models, which have as a consequence, mostly remained qualitative only. Quantification of these theories is a new and rapidly developing subject. Models include: ...
PHSC 3004 Test 3 Take Home Name__________________
... 12. The saying, the present is the key to the past, is a simple way to state the basic geological concept called ______________. 13. Sediments composed of solid fragments derived from preexisting rocks are called ______________.sediments. 14. The theory that the Earth’s lithospheric plates are in co ...
... 12. The saying, the present is the key to the past, is a simple way to state the basic geological concept called ______________. 13. Sediments composed of solid fragments derived from preexisting rocks are called ______________.sediments. 14. The theory that the Earth’s lithospheric plates are in co ...
Post-rifting Processes
... How was ENAM lithosphere formed? State of lithosphere before most recent (Mz) rifting ...
... How was ENAM lithosphere formed? State of lithosphere before most recent (Mz) rifting ...
Forcing of continental subduction and deep processes
... produced by some intrinsic strength softening mechanisms resulting in reduction of the friction angle from 33° to 5–10°. However, such mechanisms are not very well known. The other, more natural way to reduce friction on the fault would be to reduce normal stress acting on the fault plain. In ocean ...
... produced by some intrinsic strength softening mechanisms resulting in reduction of the friction angle from 33° to 5–10°. However, such mechanisms are not very well known. The other, more natural way to reduce friction on the fault would be to reduce normal stress acting on the fault plain. In ocean ...
Plate Tectonics Jeopardy
... This is the thinnest layer mostly made up of large rocks of basalt and granite. ...
... This is the thinnest layer mostly made up of large rocks of basalt and granite. ...
Hunting for oceanic island Moho
... share similar features on the radial component (Figs 2, 3, 4, 5, 6, 7, 8 and 9): a train of sharp positive-amplitude pulses arriving within the first 4 s (at all stations) which we attribute to Ps conversions from crustal layers. These are followed by a complex crustal reverberation, mostly with neg ...
... share similar features on the radial component (Figs 2, 3, 4, 5, 6, 7, 8 and 9): a train of sharp positive-amplitude pulses arriving within the first 4 s (at all stations) which we attribute to Ps conversions from crustal layers. These are followed by a complex crustal reverberation, mostly with neg ...
The South-east African margin and its marine basins and ridge
... This subproject will investigate the deep crustal structures and composition along the east margin of southern Africa, as well as the surface expressions of Mesozoic magmatic and tectonic events related to the break-up of Gondwana. This region is the most complex of the southern African Gondwana mar ...
... This subproject will investigate the deep crustal structures and composition along the east margin of southern Africa, as well as the surface expressions of Mesozoic magmatic and tectonic events related to the break-up of Gondwana. This region is the most complex of the southern African Gondwana mar ...
Exploring plate motion and deformation in California with
... 3. Interpreting the vectors in the context of the strike-slip boundary between the Pacific and North American plates. 4. Inferring an earthquake near Parkfield, CA from GPS time series data. General Procedure: See following pages for specific suggestions and answers to questions. 1. Review with your ...
... 3. Interpreting the vectors in the context of the strike-slip boundary between the Pacific and North American plates. 4. Inferring an earthquake near Parkfield, CA from GPS time series data. General Procedure: See following pages for specific suggestions and answers to questions. 1. Review with your ...
docx - UNAVCO
... 3. Interpreting the vectors in the context of the strike-slip boundary between the Pacific and North American plates. 4. Inferring an earthquake near Parkfield, CA from GPS time series data. General Procedure: See following pages for specific suggestions and answers to questions. 1. Review with your ...
... 3. Interpreting the vectors in the context of the strike-slip boundary between the Pacific and North American plates. 4. Inferring an earthquake near Parkfield, CA from GPS time series data. General Procedure: See following pages for specific suggestions and answers to questions. 1. Review with your ...
Gorringe Ridge gravity and magnetic anomalies
... basins (Purdy 1975). The main crustal structures below the ridge, however, are unknown from these previous studies. We propose simple models for the region, using density values based on the mean densities of rocks forming each one of the main bodies (Telford et al. 1990) and on the drill data. The ...
... basins (Purdy 1975). The main crustal structures below the ridge, however, are unknown from these previous studies. We propose simple models for the region, using density values based on the mean densities of rocks forming each one of the main bodies (Telford et al. 1990) and on the drill data. The ...
Earth Science Lesson 9: Earth`s History Earth looks very different
... At first, Earth did not have an atmosphere or free water since the planet was too hot for gases and water to collect. The atmosphere and oceans that we see today evolved over time. Earth’s First Atmosphere Earth’s first atmosphere was made of hydrogen and helium, the gases that were common in this r ...
... At first, Earth did not have an atmosphere or free water since the planet was too hot for gases and water to collect. The atmosphere and oceans that we see today evolved over time. Earth’s First Atmosphere Earth’s first atmosphere was made of hydrogen and helium, the gases that were common in this r ...
Plate tectonics
Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός ""pertaining to building"") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s.The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories (that still have some supporters) propose gradual shrinking (contraction) or gradual expansion of the globe.Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.