Garnet: Common Mineral, Uncommonly Useful
... metamorphic rocks. Garnet may form in rocks that are sufficiently rich in Al (or Fe3+ or Cr) and in many metamorphic contexts (i.e. contact, regional, and subductionrelated metamorphism). It usually forms at temperatures above ~400 °C and pressures above ~0.4 GPa (e.g. Spear 1993; Caddick and Kohn 2 ...
... metamorphic rocks. Garnet may form in rocks that are sufficiently rich in Al (or Fe3+ or Cr) and in many metamorphic contexts (i.e. contact, regional, and subductionrelated metamorphism). It usually forms at temperatures above ~400 °C and pressures above ~0.4 GPa (e.g. Spear 1993; Caddick and Kohn 2 ...
here - Lehigh University
... King, R. L., Bebout, G. E., Grove, M., Moriguti, T., and Nakamura, E., 2007, Boron and lead isotope signatures of subduction-zone melange formation: Hybridization and fractionation along the slab-mantle interface beneath volcanic arcs, Chemical Geology 239, 305-322. Bebout, G. E., Idleman, B. D., Li ...
... King, R. L., Bebout, G. E., Grove, M., Moriguti, T., and Nakamura, E., 2007, Boron and lead isotope signatures of subduction-zone melange formation: Hybridization and fractionation along the slab-mantle interface beneath volcanic arcs, Chemical Geology 239, 305-322. Bebout, G. E., Idleman, B. D., Li ...
`emplacement` of an ophiolite?
... and below RTI ophiolites (e.g. Lytwyn et al. 1997). The ridge-trench intersections are associated with low-pressure, high-temperature metamorphism of the rocks structurally above (and inboard) of the ophiolite (e.g. Sisson & Pavlis 1993; Brown 1998). Examples of this type of ophiolites include the R ...
... and below RTI ophiolites (e.g. Lytwyn et al. 1997). The ridge-trench intersections are associated with low-pressure, high-temperature metamorphism of the rocks structurally above (and inboard) of the ophiolite (e.g. Sisson & Pavlis 1993; Brown 1998). Examples of this type of ophiolites include the R ...
PDF
... ophiolite was gradually exposed in situ as a result of underplating of buoyant intra-oceanic crust or due to isostatic uplift when subduction stopped. For ophiolites that form in forearcs, it can be difficult to determine whether the ophiolite is autochthonous or allochthonous, but for our purposes ...
... ophiolite was gradually exposed in situ as a result of underplating of buoyant intra-oceanic crust or due to isostatic uplift when subduction stopped. For ophiolites that form in forearcs, it can be difficult to determine whether the ophiolite is autochthonous or allochthonous, but for our purposes ...
Petrology Lecture 11
... Miyashiro’s Facies Series • (1961) initially proposed five facies series, most of them named for a specific representative “type locality” The series were: 1. Contact Facies Series (very low-P) 2. Buchan or Abukuma Facies Series (low-P regional) 3. Barrovian Facies Series (medium-P regional) ...
... Miyashiro’s Facies Series • (1961) initially proposed five facies series, most of them named for a specific representative “type locality” The series were: 1. Contact Facies Series (very low-P) 2. Buchan or Abukuma Facies Series (low-P regional) 3. Barrovian Facies Series (medium-P regional) ...
Practice mdtrm
... 82. A(n) ____________________ is a solid mass of mineral or mineral-like matter that occurs naturally. 83. In an undisturbed sequence of sedimentary rocks, the oldest rocks would be at the ____________________ of the sequence. 84. The location on Earth’s surface above the point where an earthquake s ...
... 82. A(n) ____________________ is a solid mass of mineral or mineral-like matter that occurs naturally. 83. In an undisturbed sequence of sedimentary rocks, the oldest rocks would be at the ____________________ of the sequence. 84. The location on Earth’s surface above the point where an earthquake s ...
ABSTRACT The gneiss complex around and north of Pouso Alegre
... formed. Models for their origin may be related to 1) melting of Archaean gneisses, 2) eclogite melting, 3) fractionation of basaltic magma or 4) hornblende fractionation. Jahn et al. (1984) appeal to a multi-stage derivation rather than direct extraction from melting of upper mantle whereby success ...
... formed. Models for their origin may be related to 1) melting of Archaean gneisses, 2) eclogite melting, 3) fractionation of basaltic magma or 4) hornblende fractionation. Jahn et al. (1984) appeal to a multi-stage derivation rather than direct extraction from melting of upper mantle whereby success ...
Orogens and slabs vs. their direction of subduction
... Subduction zones appear primarily controlled by the polarity of their direction, i.e., W-directed or E- to NNE-directed, probably due to the westward drift of the lithosphere relative to the asthenosphere. The decollement planes behave differently in the two end-members. In the W-directed subduction ...
... Subduction zones appear primarily controlled by the polarity of their direction, i.e., W-directed or E- to NNE-directed, probably due to the westward drift of the lithosphere relative to the asthenosphere. The decollement planes behave differently in the two end-members. In the W-directed subduction ...
Full text PDF - Geochemical Perspectives
... manifest in variations in stable isotope ratios that could only have been produced at or near the surface of the Earth. In addition to a recycled component, many plumes also contain a quite primitive component, manifested primarily in their noble gas isotope ratios. The primitive component seems mo ...
... manifest in variations in stable isotope ratios that could only have been produced at or near the surface of the Earth. In addition to a recycled component, many plumes also contain a quite primitive component, manifested primarily in their noble gas isotope ratios. The primitive component seems mo ...
Exploring Geology: What-To-Know List
... Discuss factors that influence how far a magma rises toward the surface. Explain the factors that control the viscosity of a magma. Describe what factors might be combined to form very high-viscosity magma or very low-viscosity magma. 5.8 How Does Magma Solidify? Explain or sketch the proces ...
... Discuss factors that influence how far a magma rises toward the surface. Explain the factors that control the viscosity of a magma. Describe what factors might be combined to form very high-viscosity magma or very low-viscosity magma. 5.8 How Does Magma Solidify? Explain or sketch the proces ...
Earth`s interior and tectonic plates notes
... Scale • Intensity - a measure of the degree to which an earthquake is felt by people and the amount of damage caused • Uses Roman numerals I to XII • I = not felt, XII = total damage of an area • The number changes depending on where you are (highest number is close to the epicenter). ...
... Scale • Intensity - a measure of the degree to which an earthquake is felt by people and the amount of damage caused • Uses Roman numerals I to XII • I = not felt, XII = total damage of an area • The number changes depending on where you are (highest number is close to the epicenter). ...
Chapter 1- INTRODUCTION 1.1. Mantle Rocks This study is
... characterized by a metal core composed mainly by iron, nickel, and sulfur, and divided in a solid inner core and an outer liquid core, which is the main candidate to be responsible of the Earth’s magnetic field. The mantle-core transition occurs ~2800 km deep. The seismic response also distinguishes ...
... characterized by a metal core composed mainly by iron, nickel, and sulfur, and divided in a solid inner core and an outer liquid core, which is the main candidate to be responsible of the Earth’s magnetic field. The mantle-core transition occurs ~2800 km deep. The seismic response also distinguishes ...
Dynamical geochemistry of the mantle
... transition zone, and especially at the 660 km seismic discontinuity, was resolved in the negative by two arguments. The first (Davies, 1988b) is that such a compositional boundary would give rise to plumes that are much stronger than is consistent with observed hotspot swells. This argument will be ...
... transition zone, and especially at the 660 km seismic discontinuity, was resolved in the negative by two arguments. The first (Davies, 1988b) is that such a compositional boundary would give rise to plumes that are much stronger than is consistent with observed hotspot swells. This argument will be ...
Earth`s heterogeneous mantle: A product of convection
... Ubiquitous heterogeneity in the Earth's mantle has been documented by numerous chemical and isotopic analyses of oceanic basalts. Despite the ever-increasing amount of data, the way in which compositional heterogeneity is manifest in the Earth's mantle, as well as the processes leading to mantle het ...
... Ubiquitous heterogeneity in the Earth's mantle has been documented by numerous chemical and isotopic analyses of oceanic basalts. Despite the ever-increasing amount of data, the way in which compositional heterogeneity is manifest in the Earth's mantle, as well as the processes leading to mantle het ...
PDF (Chapter 23. The Upper Mantle)
... veins in a refractory matrix rather than kmsized blobs. When small amounts of melting are involved the separation tendencies are quantified by partition coefficients, which give the partitioning of a given element between the magma and the residual solid. When melting is extensive, most of the incom ...
... veins in a refractory matrix rather than kmsized blobs. When small amounts of melting are involved the separation tendencies are quantified by partition coefficients, which give the partitioning of a given element between the magma and the residual solid. When melting is extensive, most of the incom ...
Geodynamics of the Yellowstone hotspot and mantle plume: Seismic
... upper-mantle flow beneath Yellowstone at relatively high rates of 5 cm/yr that deflects the ascending plume into its west-tilted geometry. A geodynamic model of the Yellowstone plume constrained by Vp and Vs velocities and attenuation parameters suggests low excess temperatures of up to 120 K, corresp ...
... upper-mantle flow beneath Yellowstone at relatively high rates of 5 cm/yr that deflects the ascending plume into its west-tilted geometry. A geodynamic model of the Yellowstone plume constrained by Vp and Vs velocities and attenuation parameters suggests low excess temperatures of up to 120 K, corresp ...
Tectonic–climatic interaction
Tectonic–climatic interaction is the interrelationship between tectonic processes and the climate system. The tectonic processes in question include orogenesis, volcanism, and erosion, while relevant climatic processes include atmospheric circulation, orographic lift, monsoon circulation and the rain shadow effect. As the geological record of past climate changes over millions of years is sparse and poorly resolved, many questions remain unresolved regarding the nature of tectonic-climate interaction, although it is an area of active research by geologists and palaeoclimatologists.