Canada`s craton: A bottoms-up view
... and (C) the Wyoming Province (data from Pearson, 1999; Pearson et al., 2003). Shown for comparison in (A) are U-Pb ages for various events recorded in the crust of the Slave Province: metamorphic zircons and rutile in lower crustal granulite xenoliths, late “granite blooms,” and Lu-Hf and U-Pb ages ...
... and (C) the Wyoming Province (data from Pearson, 1999; Pearson et al., 2003). Shown for comparison in (A) are U-Pb ages for various events recorded in the crust of the Slave Province: metamorphic zircons and rutile in lower crustal granulite xenoliths, late “granite blooms,” and Lu-Hf and U-Pb ages ...
34 - School of Ocean and Earth Science and Technology
... When did the first continental crust form? The oldest evidence we have for continental crust is in UPb ages averaging 4.36 Ga for zircon grains in metasedimentary rocks in western Australia. These weathering-resistant grains are in ~3.6 Ga quartzrich gneisses (originally sandstones). Before being ...
... When did the first continental crust form? The oldest evidence we have for continental crust is in UPb ages averaging 4.36 Ga for zircon grains in metasedimentary rocks in western Australia. These weathering-resistant grains are in ~3.6 Ga quartzrich gneisses (originally sandstones). Before being ...
The Gaia Hypothesis - The Gaia
... How the Gaia Hypothesis was so named ... So it was then that Dr James Lovelock, in looking for the evidence of extra-terrestrial life on Mars, observed the Earth as might an extra-terrestrial, and began to formulate a method of explanation as to why the Earth appeared therefore to be not so much a p ...
... How the Gaia Hypothesis was so named ... So it was then that Dr James Lovelock, in looking for the evidence of extra-terrestrial life on Mars, observed the Earth as might an extra-terrestrial, and began to formulate a method of explanation as to why the Earth appeared therefore to be not so much a p ...
Grand Challenges in Geodynamics
... Comparative planetology has advanced the idea that the long-term evolution of a terrestrial planet may be dictated, or at least strongly influenced, by events occurring within the first 50-100 Ma of its formation. Relative to the modern Earth, the energy available for heating Earth’s interior was or ...
... Comparative planetology has advanced the idea that the long-term evolution of a terrestrial planet may be dictated, or at least strongly influenced, by events occurring within the first 50-100 Ma of its formation. Relative to the modern Earth, the energy available for heating Earth’s interior was or ...
Petrography and illite crystallinity of the Lesser Himalayan
... approximately 0.5 km southeast of Mugling (Fig. 2). This is blue-grey, and medium-bedded in outcrops. It consists of the assemblage sericite+chlorite+plagioclase+quartz+calcite. Quartz and calcite are the dominant minerals. The mineral grains are medium- to coarse-grained (maximum size of quartz: 0. ...
... approximately 0.5 km southeast of Mugling (Fig. 2). This is blue-grey, and medium-bedded in outcrops. It consists of the assemblage sericite+chlorite+plagioclase+quartz+calcite. Quartz and calcite are the dominant minerals. The mineral grains are medium- to coarse-grained (maximum size of quartz: 0. ...
Experimental Course Page 1 8/9/2004 LEHMAN COLLEGE OF THE
... considered are other Earth materials such as soil and water. Correlative learning about rock-forming minerals, petrology within the context of biogeochemical cycles (tectonic, rock, and hydrologic) is in keeping with recent conceptual shifts towards Earth systems science which views the planet in te ...
... considered are other Earth materials such as soil and water. Correlative learning about rock-forming minerals, petrology within the context of biogeochemical cycles (tectonic, rock, and hydrologic) is in keeping with recent conceptual shifts towards Earth systems science which views the planet in te ...
Morganfest brochure
... two things: the proximity of the location to the zoo, which was only a short walk away, and an absolutely absurd talk by a speaker, who literally was dragged off the stage by the moderator as he went long past his allotted time. To put it politely, I thought his concept of deep mantle plumes distinc ...
... two things: the proximity of the location to the zoo, which was only a short walk away, and an absolutely absurd talk by a speaker, who literally was dragged off the stage by the moderator as he went long past his allotted time. To put it politely, I thought his concept of deep mantle plumes distinc ...
THE UPPER MANTLE AND ALKALIC MAGMAS
... The requisite conditions for the generation of alkalic magmas directly from the mantle have yet to be established, but, from the available data, it seems likely to be induced by high heat flow from the deeper earth accompanied by torsional stress (as may be caused by inter secting convection curren ...
... The requisite conditions for the generation of alkalic magmas directly from the mantle have yet to be established, but, from the available data, it seems likely to be induced by high heat flow from the deeper earth accompanied by torsional stress (as may be caused by inter secting convection curren ...
large igneous provinces and fertile mantle
... LIPs. If the crustal thickening is due to compressional tectonics the time scales will be dictated by convergence rates. In a typical convergence belt I estimate that thickening and delamination may take 25-35 Myr. ...
... LIPs. If the crustal thickening is due to compressional tectonics the time scales will be dictated by convergence rates. In a typical convergence belt I estimate that thickening and delamination may take 25-35 Myr. ...
Seismic Anisotropy: Tracing Plate Dynamics in the Mantle
... he rocks of Earth’s upper mantle deform in the slow convective flows of our planet’s hot interior. Deformation preferentially aligns mineral crystals within rock (1–3). This alignment induces elastic anisotropy, which affects how fast seismic waves propagate in different directions. In principle, me ...
... he rocks of Earth’s upper mantle deform in the slow convective flows of our planet’s hot interior. Deformation preferentially aligns mineral crystals within rock (1–3). This alignment induces elastic anisotropy, which affects how fast seismic waves propagate in different directions. In principle, me ...
Calcium isotopic composition of mantle xenoliths and minerals from
... Recent observations have shown considerable Ca isotopic fractionation in both mineral and bulk rock scales in the upper mantle. Huang et al. (2010) observed large offsets in D44/40Ca (up to 0.75‰) between opx and cpx from peridotite xenoliths. Such large inter-mineral Ca isotopic fractionation could ...
... Recent observations have shown considerable Ca isotopic fractionation in both mineral and bulk rock scales in the upper mantle. Huang et al. (2010) observed large offsets in D44/40Ca (up to 0.75‰) between opx and cpx from peridotite xenoliths. Such large inter-mineral Ca isotopic fractionation could ...
Composition and Evolution of the Lithosphere
... floors filled with these basalts and graywackes collapsed, forming greenstone belts that also accreted to the growing protocontinent. Thus some of the early seafloor survived destruction (by subduction) and became part of the stable craton. ...
... floors filled with these basalts and graywackes collapsed, forming greenstone belts that also accreted to the growing protocontinent. Thus some of the early seafloor survived destruction (by subduction) and became part of the stable craton. ...
Earth`s Crust Test Prep
... upward in a bull’s-eye pattern 10 miles wide. There is a 4-inch rise at its center, which geologists believe could be the beginning of another volcano. The uplift was found by comparing satellite images. This uplift in Oregon may allow the tracking of a volcanic eruption from its beginning, long bef ...
... upward in a bull’s-eye pattern 10 miles wide. There is a 4-inch rise at its center, which geologists believe could be the beginning of another volcano. The uplift was found by comparing satellite images. This uplift in Oregon may allow the tracking of a volcanic eruption from its beginning, long bef ...
Student Edition Sample Chapter (3MB PDF)
... Are you faster than the speed of a moving plate on Earth’s surface? The speed of a moving plate ranges from 1 to 10 centimeters each year. On average, that’s about as fast as your fingernails grow! So, even if you are walking slowly, you are moving very quickly compared to a plate moving on Earth’s ...
... Are you faster than the speed of a moving plate on Earth’s surface? The speed of a moving plate ranges from 1 to 10 centimeters each year. On average, that’s about as fast as your fingernails grow! So, even if you are walking slowly, you are moving very quickly compared to a plate moving on Earth’s ...
Living Things - Mountain View Middle School
... 6.1.a Students know evidence of plate tectonics is derived from the fit of the continents; the location of earthquakes, volcanoes, and mid-ocean ridges; and the distribution of fossils, rock types and ancient climatic zones. ...
... 6.1.a Students know evidence of plate tectonics is derived from the fit of the continents; the location of earthquakes, volcanoes, and mid-ocean ridges; and the distribution of fossils, rock types and ancient climatic zones. ...
Shervais, J.W., Significance of Subduction
... with island arc plutonic series formed by slab melting (Drummond and Defant, 1990; Rapp et al., 2003), and it has been proposed that Archean greenstone belts may represent essentially coeval island arc volcanism (e.g., Parman and Grove, 2004; Parman et al., 2001, 2004; Polat and Kerrich, 2001, 2002, ...
... with island arc plutonic series formed by slab melting (Drummond and Defant, 1990; Rapp et al., 2003), and it has been proposed that Archean greenstone belts may represent essentially coeval island arc volcanism (e.g., Parman and Grove, 2004; Parman et al., 2001, 2004; Polat and Kerrich, 2001, 2002, ...
Cenozoic magmatism in the western Ross Embayment:
... Wilson [1963] and Morgan [1971], plume occurrence has been frequently postulated just on the basis of magma chemistry, and plume theory has been stretched to the point that at least in some instances simpler explanations can be found. This controversy should be addressed in an integrated geological ...
... Wilson [1963] and Morgan [1971], plume occurrence has been frequently postulated just on the basis of magma chemistry, and plume theory has been stretched to the point that at least in some instances simpler explanations can be found. This controversy should be addressed in an integrated geological ...
The geology of vertical movements of the lithosphere
... with A, B, C, G and H experience subsidence, leading to the development of sedimentary basins, whereas regions D, E, F, H and I illustrate the main mechanisms of uplift in mountains and plateaux. Lithospheric stretching in rift zones thins the crust, causing the surface to subside creating extension ...
... with A, B, C, G and H experience subsidence, leading to the development of sedimentary basins, whereas regions D, E, F, H and I illustrate the main mechanisms of uplift in mountains and plateaux. Lithospheric stretching in rift zones thins the crust, causing the surface to subside creating extension ...
Age of the Earth
The age of the Earth is 4.54 ± 0.05 billion years (4.54 × 109 years ± 1%). This age is based on evidence from radiometric age dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.Following the development of radiometric age dating in the early 20th century, measurements of lead in uranium-rich minerals showed that some were in excess of a billion years old.The oldest such minerals analyzed to date—small crystals of zircon from the Jack Hills of Western Australia—are at least 4.404 billion years old. Comparing the mass and luminosity of the Sun to those of other stars, it appears that the Solar System cannot be much older than those rocks. Calcium-aluminium-rich inclusions – the oldest known solid constituents within meteorites that are formed within the Solar System – are 4.567 billion years old, giving an age for the solar system and an upper limit for the age of Earth.It is hypothesised that the accretion of Earth began soon after the formation of the calcium-aluminium-rich inclusions and the meteorites. Because the exact amount of time this accretion process took is not yet known, and the predictions from different accretion models range from a few millions up to about 100 million years, the exact age of Earth is difficult to determine. It is also difficult to determine the exact age of the oldest rocks on Earth, exposed at the surface, as they are aggregates of minerals of possibly different ages.