Chapter 11
... To summarize, metamorphism is the process by which a pre-existing rock (the protolith) is altered by a change in temperature, pressure, or by contact with chemically reactive fluids, or by any combination of these three parameters. The alteration process is a recrystallization event, where the initi ...
... To summarize, metamorphism is the process by which a pre-existing rock (the protolith) is altered by a change in temperature, pressure, or by contact with chemically reactive fluids, or by any combination of these three parameters. The alteration process is a recrystallization event, where the initi ...
L.S. Normore - Department of Natural Resources
... The Random Island map area has a long and protracted history of geological investigations. Early work concentrated on detailed stratigraphic interpretations of post-Cambrian rocks (Matthew, 1899; Walcott, 1900; van Ingen, 1914; Howell, 1926). The first comprehensive geological mapping project to inc ...
... The Random Island map area has a long and protracted history of geological investigations. Early work concentrated on detailed stratigraphic interpretations of post-Cambrian rocks (Matthew, 1899; Walcott, 1900; van Ingen, 1914; Howell, 1926). The first comprehensive geological mapping project to inc ...
Gem Corundum in Alkali Basalt: Origin and Occurrence
... To understand figure 2, it is essential to recognize that most rock types are composed of more than one mineral, and each mineral, or combination of minerals, has a specific melting temperature that is influenced by pressure, the amount of water present, and other factors. The process of 'partial me ...
... To understand figure 2, it is essential to recognize that most rock types are composed of more than one mineral, and each mineral, or combination of minerals, has a specific melting temperature that is influenced by pressure, the amount of water present, and other factors. The process of 'partial me ...
Extension Tectonics - Processes in Structural Geology and Tectonics
... So, surface thinning of “block” (upper crust) results in upward flow of “water” (lower crust). In MCCs, thinning by normal faulting results in exhumation of deeper detachment and basement rock. ...
... So, surface thinning of “block” (upper crust) results in upward flow of “water” (lower crust). In MCCs, thinning by normal faulting results in exhumation of deeper detachment and basement rock. ...
Geological framework and mineralization of Papua New Guinea
... The Geology and Mineral Potential of Papua New Guinea (PNG) was outlined in a volume published in 2005 (Williamson and Hancock, 2005). This technical note revises and updates chapters 4–6 from that volume, and also adds new information from references published since. The detailed knowledge of the e ...
... The Geology and Mineral Potential of Papua New Guinea (PNG) was outlined in a volume published in 2005 (Williamson and Hancock, 2005). This technical note revises and updates chapters 4–6 from that volume, and also adds new information from references published since. The detailed knowledge of the e ...
Delaware Piedmont Geology - The Delaware Geological Survey
... Plate Tectonics The Earth’s crust, although solid, is continuously in motion. Sometimes the movements are quick and easily observed, such as erupting volcanoes or earthquakes. Sometimes the changes are slow and more difficult to recognize, such as uplift and erosion. For many years geologists recor ...
... Plate Tectonics The Earth’s crust, although solid, is continuously in motion. Sometimes the movements are quick and easily observed, such as erupting volcanoes or earthquakes. Sometimes the changes are slow and more difficult to recognize, such as uplift and erosion. For many years geologists recor ...
Late Precambrian Stratigraphy and Structure of the North
... Late Precambrian (Riphean and Vendian) rocks occur along the north-eastern margin of the Fennoscandian Shield and the Russian Platform in three zones: 1) the Varanger-Kildin, 2) the Timan-Kanin and 3) the Southern Barents Shelf zones. The last occupies an intermediate position and is entirely covere ...
... Late Precambrian (Riphean and Vendian) rocks occur along the north-eastern margin of the Fennoscandian Shield and the Russian Platform in three zones: 1) the Varanger-Kildin, 2) the Timan-Kanin and 3) the Southern Barents Shelf zones. The last occupies an intermediate position and is entirely covere ...
Archean Geodynamics and the Thermal Evolution of Earth
... express Q as a function of internal temperature, which is in turn a function of time. Thus, Q(t) is parameterized as Q(Ti(t)). The details of this parameterization are given later in this section (section 2.3 and section 2.5). The above ordinary differential equation can be integrated either forward ...
... express Q as a function of internal temperature, which is in turn a function of time. Thus, Q(t) is parameterized as Q(Ti(t)). The details of this parameterization are given later in this section (section 2.3 and section 2.5). The above ordinary differential equation can be integrated either forward ...
The Moho in subduction zones - Earth and Space Sciences at the
... The Moho in subduction zones exists in two distinct forms, one associated with the subducting oceanic plate and second with the overriding plate. The seismic expression of both forms is linked to the nature of a landward dipping, low-velocity zone (LVZ) that has been detected in a majority of subduc ...
... The Moho in subduction zones exists in two distinct forms, one associated with the subducting oceanic plate and second with the overriding plate. The seismic expression of both forms is linked to the nature of a landward dipping, low-velocity zone (LVZ) that has been detected in a majority of subduc ...
Unraveling topography around subduction zones from
... bathymetry of the overriding plate, a deep trench, an outer rise (or forebulge). This structure correlates well with the gravity signal, in particular long wavelength geoid highs that correspond to the density anomalies of the subducted slabs, overprinted by sharp free air lows over the trenches tha ...
... bathymetry of the overriding plate, a deep trench, an outer rise (or forebulge). This structure correlates well with the gravity signal, in particular long wavelength geoid highs that correspond to the density anomalies of the subducted slabs, overprinted by sharp free air lows over the trenches tha ...
Mantle hotspot neon in basalts from the Northwest Lau Back
... helium and neon isotope variations in lavas from the Northwest Lau Back-arc Basin, which is one of three back-arc extensional zones in the northern Lau Basin (Figure 1). [3] Lavas from the Northwest Lau Back-arc Basin are known to have anomalous helium isotope ratios compared to what is expected for ...
... helium and neon isotope variations in lavas from the Northwest Lau Back-arc Basin, which is one of three back-arc extensional zones in the northern Lau Basin (Figure 1). [3] Lavas from the Northwest Lau Back-arc Basin are known to have anomalous helium isotope ratios compared to what is expected for ...
Thermal thickness of the Earth`s lithosphere: a numerical model
... phere from Eqs. (8) and (14), the “standard” lithos phere column with a known thickness of the lithos phere, gravity anomaly, and density distribution should be specified for unambiguous definition of one of the parts of Eq. (8) in addition to the data on the structure of lithosphere, gravity anom ...
... phere from Eqs. (8) and (14), the “standard” lithos phere column with a known thickness of the lithos phere, gravity anomaly, and density distribution should be specified for unambiguous definition of one of the parts of Eq. (8) in addition to the data on the structure of lithosphere, gravity anom ...
McLelland, JM, Selleck, BW, and Bickford, ME, 2010
... ADK—Adirondack outlier (McLelland, this volume). References for geochronology in the following abbreviated localities may be found in the text (under Mesoproterozoic Inliers of the Appalachians): ...
... ADK—Adirondack outlier (McLelland, this volume). References for geochronology in the following abbreviated localities may be found in the text (under Mesoproterozoic Inliers of the Appalachians): ...
petrogenesis of the oligocene east tintic volcanic field, utah
... obtained a similar argon age (34.83 ± 0.15 Ma) for the Fernow to the south in Sage Valley. East Tintic magmatism continued until at least 32.70 ± 0.28 Ma (table 1). The two “SP” samples in table 1 are from locations just north of the East Tintic Mountains and are from units that overlie possibly the ...
... obtained a similar argon age (34.83 ± 0.15 Ma) for the Fernow to the south in Sage Valley. East Tintic magmatism continued until at least 32.70 ± 0.28 Ma (table 1). The two “SP” samples in table 1 are from locations just north of the East Tintic Mountains and are from units that overlie possibly the ...
"postorogenie" magmatism
... these "postorogenie" magmatic suites, the critical geodynamic problems related to their genesis remain unanswered. However, the geodynamic and compositional data allow some inferences regarding their origin. First, the broad distribution of "postorogenie" magmatic suites through space and time sugge ...
... these "postorogenie" magmatic suites, the critical geodynamic problems related to their genesis remain unanswered. However, the geodynamic and compositional data allow some inferences regarding their origin. First, the broad distribution of "postorogenie" magmatic suites through space and time sugge ...
THE SETTING OF OROGENIC, AURIFEROUS QUARTZ VEINS AT
... exposed, an extensive new industry and government geological database for the region indicates that the deposit comprises a series of en-echelon-style, east- to east-northeast-trending, auriferous quartz veins hosted near the sandstone–shale transition in the uppermost sections of the Exploits Rapid ...
... exposed, an extensive new industry and government geological database for the region indicates that the deposit comprises a series of en-echelon-style, east- to east-northeast-trending, auriferous quartz veins hosted near the sandstone–shale transition in the uppermost sections of the Exploits Rapid ...
The lithosphere under stress
... continental lithosphere, primarily due to its usually younger age and its consistent mode of formation at mid-ocean ridges. Keywords: lithosphere definitions; elastic thickness; rheology; mantle temperature; subsidence; plate model ...
... continental lithosphere, primarily due to its usually younger age and its consistent mode of formation at mid-ocean ridges. Keywords: lithosphere definitions; elastic thickness; rheology; mantle temperature; subsidence; plate model ...
Geological Society, London, Special Publications
... processes. The Pasagshak Point Thrust preserves three distinct fault rock textures, which are mutually cross-cutting, and can be correlated to different strain rates. Ultrafine-grained black fault rocks, including pseudotachylyte, were formed during seismic slip on layers up to 30 cm thick. Well-org ...
... processes. The Pasagshak Point Thrust preserves three distinct fault rock textures, which are mutually cross-cutting, and can be correlated to different strain rates. Ultrafine-grained black fault rocks, including pseudotachylyte, were formed during seismic slip on layers up to 30 cm thick. Well-org ...
Thermal evolution of the Earth as recorded by komatiites
... Further investigation of Archean terranes led to the recognition of komatiites that range from Archean to Cretaceous in age [13] with most occurring between 3.5 and 1.5 Ga and a peak in komatiite preservation occurring in the late Archean. Recent discoveries of komatiites include a Phanerozoic occur ...
... Further investigation of Archean terranes led to the recognition of komatiites that range from Archean to Cretaceous in age [13] with most occurring between 3.5 and 1.5 Ga and a peak in komatiite preservation occurring in the late Archean. Recent discoveries of komatiites include a Phanerozoic occur ...
Evolution of the continental crust
... evolution of this planet, and yet when and how it formed remain the topic of considerable debate. Significant obstacles to understanding this evolution include the shortage of rocks from the first billion years of Earth history and that fact that rocks amenable to study on the surface are very diffe ...
... evolution of this planet, and yet when and how it formed remain the topic of considerable debate. Significant obstacles to understanding this evolution include the shortage of rocks from the first billion years of Earth history and that fact that rocks amenable to study on the surface are very diffe ...
Spreading Continents Kick-Started Plate Tectonics Plate tectonics
... comparable to that of present-day tectonic forces driving orogenesis1. To explore the tectonic impact ...
... comparable to that of present-day tectonic forces driving orogenesis1. To explore the tectonic impact ...
Crustal Shortening and Extension in the Central Andes: Insights
... significant extension in the High Andes, but the seismic data show crustal shortening concentrated in the sub-Andean thrust belt at a much lower rate (< 3 mm yr-1) and limited crustal extension in the High Andes with variable directions, and the geological data suggest 10~15 mm yr-1 crustal shorteni ...
... significant extension in the High Andes, but the seismic data show crustal shortening concentrated in the sub-Andean thrust belt at a much lower rate (< 3 mm yr-1) and limited crustal extension in the High Andes with variable directions, and the geological data suggest 10~15 mm yr-1 crustal shorteni ...
History of geology
The history of geology is concerned with the development of the natural science of geology. Geology is the scientific study of the origin, history, and structure of the Earth. Throughout the ages geology provides essential theories and data that shape how society conceptualizes the Earth.