Insights into extensional processes during magma assisted rifting
... magmatic intrusion. The Main Ethiopian Rift (MER), part of the East African Rift System, is an ideal location to study this transition because it captures rifting processes during continental breakup. In this contribution we synthesise geochemical data from scoria cones in the Wonji Fault Belt (WFB) ...
... magmatic intrusion. The Main Ethiopian Rift (MER), part of the East African Rift System, is an ideal location to study this transition because it captures rifting processes during continental breakup. In this contribution we synthesise geochemical data from scoria cones in the Wonji Fault Belt (WFB) ...
PNAS-2014-Anderson-1..
... parallel to linear volcanic chains (4–6). These wide features would have to be due to unresolved narrow (<200 km diameter) conduits if there is any validity to the mantle plume hypothesis. In addition, these hypothetical narrow conduits would have to be significantly hotter, and to be ascending at s ...
... parallel to linear volcanic chains (4–6). These wide features would have to be due to unresolved narrow (<200 km diameter) conduits if there is any validity to the mantle plume hypothesis. In addition, these hypothetical narrow conduits would have to be significantly hotter, and to be ascending at s ...
Mantle Exhumation in an Early Paleozoic Passive Margin, Northern
... relatively young mantle lithosphere with an age only slightly older than the Devonian metasedimentary rocks in which it is hosted or mantle that is metasomatized in the same events related to rifting. The rocks in the study area bear striking similarities to those in and surrounding the Zabargad (Re ...
... relatively young mantle lithosphere with an age only slightly older than the Devonian metasedimentary rocks in which it is hosted or mantle that is metasomatized in the same events related to rifting. The rocks in the study area bear striking similarities to those in and surrounding the Zabargad (Re ...
MANTLE- AND CRUST-DERIVED MAGMATISM IN THE
... lower εNd(t) compared with the TIB. The sources of the mafic magmatism can be interpreted in terms of a depleted mantle, variously overprinted by fluids and melts from subducted slabs. In the west (TIB), H2O-dominated fluids percolated and prepared shallower (lower Ce/Yb; spinel lherzolite field) ma ...
... lower εNd(t) compared with the TIB. The sources of the mafic magmatism can be interpreted in terms of a depleted mantle, variously overprinted by fluids and melts from subducted slabs. In the west (TIB), H2O-dominated fluids percolated and prepared shallower (lower Ce/Yb; spinel lherzolite field) ma ...
From Source to Sinks in Auriferous Magmatic
... Porphyry-type systems are spatially and genetically associated with porphyritic intrusions. The stocks are of calcalkaline to alkaline composition and oxidized. The stocks are characterized by hydrous phenocryst phases, such as amphibole and biotite, whose stability requires at least 4 wt% H 2O in ...
... Porphyry-type systems are spatially and genetically associated with porphyritic intrusions. The stocks are of calcalkaline to alkaline composition and oxidized. The stocks are characterized by hydrous phenocryst phases, such as amphibole and biotite, whose stability requires at least 4 wt% H 2O in ...
Geological Society of America Bulletin
... and biological events, has been studied mostly from indirect, often distal, geochemical and biotic evidence. We have upgraded existing geologic mapping in central Panama with more than 2000 field stations, over 40 petrographic analyses, and more than 30 new geochronological and thermochronological a ...
... and biological events, has been studied mostly from indirect, often distal, geochemical and biotic evidence. We have upgraded existing geologic mapping in central Panama with more than 2000 field stations, over 40 petrographic analyses, and more than 30 new geochronological and thermochronological a ...
Earth`s first two billion years—The era of internally
... Earth’s first two billion years—The era of internally mobile crust oceanic crust between landmasses. (Moyen et al., 2006, reported a high-pressure, low-temperature Mesoarchean meta-amphibolite within normal rocks, but their published data do not establish that the minerals used for thermobarometry ...
... Earth’s first two billion years—The era of internally mobile crust oceanic crust between landmasses. (Moyen et al., 2006, reported a high-pressure, low-temperature Mesoarchean meta-amphibolite within normal rocks, but their published data do not establish that the minerals used for thermobarometry ...
Post-Paleozoic activity
... Rocks within these basins compose the Newark Supergroup (Fig. 4; see discussions later in this chapter by Olsen and by McHone and Puffer). In North America the Newark Supergroup is a synrift unit that consists primarily of gray-to-black siltstones and shales, red-brown mudstones, petromict conglomer ...
... Rocks within these basins compose the Newark Supergroup (Fig. 4; see discussions later in this chapter by Olsen and by McHone and Puffer). In North America the Newark Supergroup is a synrift unit that consists primarily of gray-to-black siltstones and shales, red-brown mudstones, petromict conglomer ...
GEOLOGICAL RELATIONSHIPS IN NORTHWESTERN FOGO
... Figure 2 (Kerr, 2013; based in part on Baird, 1958; Currie, 1997a). The geology of the area discussed in this report is shown in simplified form in Figure 4. The discussion below is confined to the sedimentary and volcanic rocks, which occur mostly along the west coast, although they are present loc ...
... Figure 2 (Kerr, 2013; based in part on Baird, 1958; Currie, 1997a). The geology of the area discussed in this report is shown in simplified form in Figure 4. The discussion below is confined to the sedimentary and volcanic rocks, which occur mostly along the west coast, although they are present loc ...
Advances in the geology of the Tobacco Root Mountains, Montana
... gneiss is continuous from one suite to the other (Harms et al., 2004, this volume, Chapter 10). On this basis, where no distinction need be made between the Indian Creek and Pony–Middle Mountain Metamorphic Suites we will refer to them together simply as the quartzofeldspathic gneiss suite. We favor ...
... gneiss is continuous from one suite to the other (Harms et al., 2004, this volume, Chapter 10). On this basis, where no distinction need be made between the Indian Creek and Pony–Middle Mountain Metamorphic Suites we will refer to them together simply as the quartzofeldspathic gneiss suite. We favor ...
The strength of faults in the crust in the western
... There are also questions concerning whether µ* is the same for all faults in a region, or whether it is even constant along strike on the same fault. For example, in California, Scholz (2000a) infers Byerlee friction not only on the San Andreas fault, but on all nearby faults as well (“strong fault ...
... There are also questions concerning whether µ* is the same for all faults in a region, or whether it is even constant along strike on the same fault. For example, in California, Scholz (2000a) infers Byerlee friction not only on the San Andreas fault, but on all nearby faults as well (“strong fault ...
1 - Assets - Cambridge - Cambridge University Press
... characteristics of sedimentary rocks are in themselves reason enough to study sedimentary rocks. In addition, many sedimentary rocks contain minerals and fossil fuels that have economic significance. Petroleum, natural gas, coal, salt, phosphorus, sulfur, iron and other metallic ores, and uranium ar ...
... characteristics of sedimentary rocks are in themselves reason enough to study sedimentary rocks. In addition, many sedimentary rocks contain minerals and fossil fuels that have economic significance. Petroleum, natural gas, coal, salt, phosphorus, sulfur, iron and other metallic ores, and uranium ar ...
Relations between sedimentary basins and petroleum
... segments, known as plates, which move relative to one another. The term plate tectonics also refers to that branch of the geological sciences which studies the morphology and movements of plates, and the various phenomena affecting them. This fragmentation and movement, responsible for the current c ...
... segments, known as plates, which move relative to one another. The term plate tectonics also refers to that branch of the geological sciences which studies the morphology and movements of plates, and the various phenomena affecting them. This fragmentation and movement, responsible for the current c ...
A Comparative Study of the Badger Pass Igneous Intrusion and the
... The igneous rocks of these two areas--the McDowell Springs area and the Badger Pass area--separated by several kilometers of horizontal distance and over one hundred meters of elevation, differ in field appearance, and distinguish themselves through their dissimilar structural relationships to their ...
... The igneous rocks of these two areas--the McDowell Springs area and the Badger Pass area--separated by several kilometers of horizontal distance and over one hundred meters of elevation, differ in field appearance, and distinguish themselves through their dissimilar structural relationships to their ...
evolution of the north american cordillera
... assembled in Neoproterozoic time (800–550 Ma) by juxtaposition of continental fragments across multiple internal suture belts (Meert & Van der Voo 1997). Laurasia included the ancient continental nuclei of Laurentia (North America) and Baltica (Europe), which had been conjoined in early Paleozoic ti ...
... assembled in Neoproterozoic time (800–550 Ma) by juxtaposition of continental fragments across multiple internal suture belts (Meert & Van der Voo 1997). Laurasia included the ancient continental nuclei of Laurentia (North America) and Baltica (Europe), which had been conjoined in early Paleozoic ti ...
EVOLUTION OF THE NORTH AMERICAN CORDILLERA William R
... assembled in Neoproterozoic time (800–550 Ma) by juxtaposition of continental fragments across multiple internal suture belts (Meert & Van der Voo 1997). Laurasia included the ancient continental nuclei of Laurentia (North America) and Baltica (Europe), which had been conjoined in early Paleozoic ti ...
... assembled in Neoproterozoic time (800–550 Ma) by juxtaposition of continental fragments across multiple internal suture belts (Meert & Van der Voo 1997). Laurasia included the ancient continental nuclei of Laurentia (North America) and Baltica (Europe), which had been conjoined in early Paleozoic ti ...
46_1996_Ilg et al_GSABull_Tectonic evolution in GC
... Paleoproterozoic supracrustal rocks of the Upper Granite Gorge are divided into three mappable units: the Rama, Brahma, and Vishnu Schists, here collectively named the “Granite Gorge Metamorphic Suite.” The Brahma Schist consists of mafic to intermediate-composition metavolcanic rocks that have yiel ...
... Paleoproterozoic supracrustal rocks of the Upper Granite Gorge are divided into three mappable units: the Rama, Brahma, and Vishnu Schists, here collectively named the “Granite Gorge Metamorphic Suite.” The Brahma Schist consists of mafic to intermediate-composition metavolcanic rocks that have yiel ...
Kings Mountain National Military Park Geologic Resources Inventory
... Park in South Carolina, which the Geologic Resources Division produced in collaboration with its partners. It contains information relevant to resource management and scientific research. This document incorporates preexisting geologic information and does not include new data or additional fieldwor ...
... Park in South Carolina, which the Geologic Resources Division produced in collaboration with its partners. It contains information relevant to resource management and scientific research. This document incorporates preexisting geologic information and does not include new data or additional fieldwor ...
Divergent Plate Boundaries - North Coast Distance Education
... Remarkably, the midoceanic ridge is a nearly continuous feature around the entire globe, like the seam of a baseball (Figure 19.1). The ridge extends from the Arctic Basin, down through the center of the Atlantic, into the Indian Ocean, and across the South Pacific, ending in the Gulf of California, ...
... Remarkably, the midoceanic ridge is a nearly continuous feature around the entire globe, like the seam of a baseball (Figure 19.1). The ridge extends from the Arctic Basin, down through the center of the Atlantic, into the Indian Ocean, and across the South Pacific, ending in the Gulf of California, ...
Mission Moho Workshop: Drilling Through the Oceanic Crust to the
... consensus that the first priority for a Mission Moho should be a deep, full crustal penetration hole through the Moho and into the uppermost mantle at a single site and that the first full-penetration hole should be in fast-spread ocean crust. Although only about 20% of modern ridges are spreading a ...
... consensus that the first priority for a Mission Moho should be a deep, full crustal penetration hole through the Moho and into the uppermost mantle at a single site and that the first full-penetration hole should be in fast-spread ocean crust. Although only about 20% of modern ridges are spreading a ...
M44-2002-C24-eng - Publications du gouvernement du Canada
... occurrences have been collected and processed for geochemical analysis. This involves whole-rock ore analysis only, but sulphide separates (pyrite, sphalerite, pyrrhotite, and chalcopyrite) will be available for future analysis. This includes samples from GSC archives, Hudson Bay Exploration and Dev ...
... occurrences have been collected and processed for geochemical analysis. This involves whole-rock ore analysis only, but sulphide separates (pyrite, sphalerite, pyrrhotite, and chalcopyrite) will be available for future analysis. This includes samples from GSC archives, Hudson Bay Exploration and Dev ...
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.