Nature template
... correlation with the approximate thickness of the fast velocity lid seen by surface waves2,3. Later arrivals are well-modelled as reverberated Moho phases. The depth predicted for the direct conversion from 97 km varies within the first three epicentral bins (35 to 50) due to the interference with ...
... correlation with the approximate thickness of the fast velocity lid seen by surface waves2,3. Later arrivals are well-modelled as reverberated Moho phases. The depth predicted for the direct conversion from 97 km varies within the first three epicentral bins (35 to 50) due to the interference with ...
The Mings Bight Ophiolite Complex, Newfoundland: Appalachian
... eastward vergence at the northern end of the Baie Verte Lineament. This narrow ophiolitic belt, and (to the south) an adjacent zone of early Devonian volcanic rocks and sediments, were affected by a strong Acadian (Middle Devonian?) deformation between more resistant blocks consisting mainly of rock ...
... eastward vergence at the northern end of the Baie Verte Lineament. This narrow ophiolitic belt, and (to the south) an adjacent zone of early Devonian volcanic rocks and sediments, were affected by a strong Acadian (Middle Devonian?) deformation between more resistant blocks consisting mainly of rock ...
Lithosphere delamination in continental collisional orogens: A
... many orogens in the Alpine-Himalayan collisional belt such as the Tibetan Plateau [Bird, 1978; Jimenez-Munt et al., 2008], the Anatolia [Keskin, 2003; Gogus and Pysklywec, 2008a], the Apennines [Giacomuzzi et al., 2011; Chiarabba et al., 2014], and the Alboran Sea [Seber et al., 1996; Timoulalia et ...
... many orogens in the Alpine-Himalayan collisional belt such as the Tibetan Plateau [Bird, 1978; Jimenez-Munt et al., 2008], the Anatolia [Keskin, 2003; Gogus and Pysklywec, 2008a], the Apennines [Giacomuzzi et al., 2011; Chiarabba et al., 2014], and the Alboran Sea [Seber et al., 1996; Timoulalia et ...
Hoggar Shield gold mineralization- Khoudour
... bearing field Tiririne studies [3, 4, 5], this type veins consist of several generations of quartz. Gold only occurs in “young” quartz that has pink color and creates exfoliation joints and “gas chambers” in it. Low sulphide mineralzation represented by pyrite, chalcopyrite, galenite, fahlites, spha ...
... bearing field Tiririne studies [3, 4, 5], this type veins consist of several generations of quartz. Gold only occurs in “young” quartz that has pink color and creates exfoliation joints and “gas chambers” in it. Low sulphide mineralzation represented by pyrite, chalcopyrite, galenite, fahlites, spha ...
Geochemistry, origin, and U-Pb zircon ages of the Sierra Cuchillo
... Abstract—Eocene-Oligocene volcanism in New Mexico, Colorado, Arizona, and west Texas is commonly thought of as regional ash flow tuffs associated with Rio Grande rift calderas, although intermediate-composition volcanism also built stratovolcanos. The Sierra Cuchillo laccolith in Sierra County, New ...
... Abstract—Eocene-Oligocene volcanism in New Mexico, Colorado, Arizona, and west Texas is commonly thought of as regional ash flow tuffs associated with Rio Grande rift calderas, although intermediate-composition volcanism also built stratovolcanos. The Sierra Cuchillo laccolith in Sierra County, New ...
Provenance of plutonic detritus in cover sandstones of Nicoya
... Detritus derived from igneous intrusive rocks in Cretaceous cover sandstones was first detected during analysis of main framework grains (Calvo, 1998). On the basis of depositional environment and age, 20 sandstone samples were selected for this study. They were collected from three different locati ...
... Detritus derived from igneous intrusive rocks in Cretaceous cover sandstones was first detected during analysis of main framework grains (Calvo, 1998). On the basis of depositional environment and age, 20 sandstone samples were selected for this study. They were collected from three different locati ...
Two-dimensional simulations of surface deformation caused by slab
... Detachment of the deeper part of subducted lithosphere causes changes in a subduction zone system which may be observed on the Earth’s surface. Constraints on the expected magnitudes of these surface effects can aid in the interpretation of geological observations near convergent plate margins where ...
... Detachment of the deeper part of subducted lithosphere causes changes in a subduction zone system which may be observed on the Earth’s surface. Constraints on the expected magnitudes of these surface effects can aid in the interpretation of geological observations near convergent plate margins where ...
Full issue - Geological Society of America
... 4.1 Ga in NW Canada, 4.0 Ga in Wyoming, 3.9 Ga in central Canada, Labrador, and SW Greenland, 3.8 Ga in China, 3.7 Ga in NW Australia and South Africa, and 3.6 Ga in West Africa, as reported by various authors. Most zircon ages in these migmatites are, however, much younger, with wide variations bet ...
... 4.1 Ga in NW Canada, 4.0 Ga in Wyoming, 3.9 Ga in central Canada, Labrador, and SW Greenland, 3.8 Ga in China, 3.7 Ga in NW Australia and South Africa, and 3.6 Ga in West Africa, as reported by various authors. Most zircon ages in these migmatites are, however, much younger, with wide variations bet ...
6th Reading Summer Work
... convince publishing houses to publish a novel that he had written. He reasoned that if the novel, which included schwa words, was published by a major publisher, the schwa would then, by default, be added to the English language. Since there is no authoritative organization that decides which letter ...
... convince publishing houses to publish a novel that he had written. He reasoned that if the novel, which included schwa words, was published by a major publisher, the schwa would then, by default, be added to the English language. Since there is no authoritative organization that decides which letter ...
The tonalite–trondhjemite–granodiorite (TTG)
... are more abundant in the older gneisses. The TTG suite consists of calcic to marginally calc-alkalic rocks that straddle the boundaries between metaluminous and peraluminous and between ferroan and magnesian compositions. Rare-earth element (REE) patterns of these rocks may be highly fractionated wi ...
... are more abundant in the older gneisses. The TTG suite consists of calcic to marginally calc-alkalic rocks that straddle the boundaries between metaluminous and peraluminous and between ferroan and magnesian compositions. Rare-earth element (REE) patterns of these rocks may be highly fractionated wi ...
the Scanned PDF
... that in making this assumption we were treating a large number of variables in terms of only a small number of parameters, but it was hoped that some significant results might show through the "noise" in the wide scatterresultingfrom such a procedure. We have explored a method of investigation or a ...
... that in making this assumption we were treating a large number of variables in terms of only a small number of parameters, but it was hoped that some significant results might show through the "noise" in the wide scatterresultingfrom such a procedure. We have explored a method of investigation or a ...
u series disequilibria: insights into mantle melting and
... and melt-matrix interaction); (2) the elapse of time since the fractionation event during which radioactive decay will occur (e.g., melt transport time from mantle source regions to the crust, residence time in crustal magma reservoirs, and time since lava eruption); and (3) surface weathering or hy ...
... and melt-matrix interaction); (2) the elapse of time since the fractionation event during which radioactive decay will occur (e.g., melt transport time from mantle source regions to the crust, residence time in crustal magma reservoirs, and time since lava eruption); and (3) surface weathering or hy ...
Earthquakes
... a strike-slip fault, the rocks on either side of the middle. fault slip past each other sideways, with little up or The stress force called compression squeezes rock down motion. until it folds or breaks. A fold inthat rock that bends upward into is an Stress pushes a mass of rock in an twoarch oppo ...
... a strike-slip fault, the rocks on either side of the middle. fault slip past each other sideways, with little up or The stress force called compression squeezes rock down motion. until it folds or breaks. A fold inthat rock that bends upward into is an Stress pushes a mass of rock in an twoarch oppo ...
Caribbean Basins - Red Cubana de la Ciencia
... rocks exposed on the island of Hispaniola may represent the continuation of the Grenada and Yucatfin back-arc basins in this area (Fig. 2). Deformation of Caribbean crust and basin formation ...
... rocks exposed on the island of Hispaniola may represent the continuation of the Grenada and Yucatfin back-arc basins in this area (Fig. 2). Deformation of Caribbean crust and basin formation ...
On subducting slab entrainment of buoyant asthenosphere
... we study the question of how efficiently a subducting slab will entrain buoyant asthenosphere near a subduction zone, a question that leads to a better understanding of the behaviour of the asthenosphere–lithosphere system in mantle convection. There exist several different views on what exactly is ast ...
... we study the question of how efficiently a subducting slab will entrain buoyant asthenosphere near a subduction zone, a question that leads to a better understanding of the behaviour of the asthenosphere–lithosphere system in mantle convection. There exist several different views on what exactly is ast ...
crustal movements in the inner zone of southwest - J
... al., 1988; ITO, 1988). It seems that most earthquakes that occur inland sufficiently far from the subduction zone are restricted to the upper crust, in other words, a seismic-aseismic transition occurs at the mid-crustal depth. The thermal dependence of fracture strength of rock has been discussed t ...
... al., 1988; ITO, 1988). It seems that most earthquakes that occur inland sufficiently far from the subduction zone are restricted to the upper crust, in other words, a seismic-aseismic transition occurs at the mid-crustal depth. The thermal dependence of fracture strength of rock has been discussed t ...
Early Ordovician rifting of Avalonia and birth of the Rheic Ocean: U
... O’Brien et al. 1996). Shortly after their eruption, these sequences were intruded by calk-alkaline plutonic complexes, of which the Holyrood and Simmonds Brook intrusive suites have both been dated at 620 2 Ma (Krogh et al. 1988; O’Brien et al. 1995). Sm–Nd and Pb isotopic characteristics and ages ...
... O’Brien et al. 1996). Shortly after their eruption, these sequences were intruded by calk-alkaline plutonic complexes, of which the Holyrood and Simmonds Brook intrusive suites have both been dated at 620 2 Ma (Krogh et al. 1988; O’Brien et al. 1995). Sm–Nd and Pb isotopic characteristics and ages ...
Chapter Twelve: Intrusive Rocks
... Barker et al., 1986). Most plutons fall within the “Coast plutonic complex belts I and II” of Brew and Morrell (1983). These are regions underlain dominantly by (I) 45-54 Ma granodiorite and quartz monzonite and (II) mid Tertiary, Late Cretaceous and older non-migmatitic tonalite orthogneiss and wea ...
... Barker et al., 1986). Most plutons fall within the “Coast plutonic complex belts I and II” of Brew and Morrell (1983). These are regions underlain dominantly by (I) 45-54 Ma granodiorite and quartz monzonite and (II) mid Tertiary, Late Cretaceous and older non-migmatitic tonalite orthogneiss and wea ...
From mud to granite: The Cooma metamorphic sequence
... The texture and mineralogy of the rocks provides a relative scheme to distinguish between low-grade and high-grade metamorphic rocks, but they can’t be used to reconstruct the exact conditions of formation. To solve this problem, researchers conducted many laboratory experiments in which mud rocks w ...
... The texture and mineralogy of the rocks provides a relative scheme to distinguish between low-grade and high-grade metamorphic rocks, but they can’t be used to reconstruct the exact conditions of formation. To solve this problem, researchers conducted many laboratory experiments in which mud rocks w ...
Exhumation of (ultra-)high-pressure terranes: concepts
... Abstract. The formation and exhumation of high and ultrahigh-pressure, (U)HP, rocks of crustal origin appears to be ubiquitous during Phanerozoic plate subduction and continental collision events. Exhumation of (U)HP material has been shown in some orogens to have occurred only once, during a single ...
... Abstract. The formation and exhumation of high and ultrahigh-pressure, (U)HP, rocks of crustal origin appears to be ubiquitous during Phanerozoic plate subduction and continental collision events. Exhumation of (U)HP material has been shown in some orogens to have occurred only once, during a single ...
No Slide Title
... In 1912 Alfred Wegener first proposed the theory that all of the continents formed when one giant continent broke apart. Wegener used the shape of the continents, the distribution of fossils, and similarity of rocks at different parts of the world as evidence. Wegener’s Continental Drift theory was ...
... In 1912 Alfred Wegener first proposed the theory that all of the continents formed when one giant continent broke apart. Wegener used the shape of the continents, the distribution of fossils, and similarity of rocks at different parts of the world as evidence. Wegener’s Continental Drift theory was ...
geology and chromite deposits of the camaguey district camaguey
... beds, tentatively dated as Lower Cretaceous (Neocomian?). It was impossible, however, to map these formations as units in the field. CRETACEOUS ROCKS A series of volcanic rocks with interbedded limestones and radiolarian cherts lies unconformably on the serpentine. The volcanic sequence is composed ...
... beds, tentatively dated as Lower Cretaceous (Neocomian?). It was impossible, however, to map these formations as units in the field. CRETACEOUS ROCKS A series of volcanic rocks with interbedded limestones and radiolarian cherts lies unconformably on the serpentine. The volcanic sequence is composed ...
Large igneous province
A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including liquid rock (intrusive) or volcanic rock formations (extrusive), when hot magma extrudes from inside the Earth and flows out. The source of many or all LIPs is variously attributed to mantle plumes or to processes associated with plate tectonics. Types of LIPs can include large volcanic provinces (LVP), created through flood basalt and large plutonic provinces (LPP). Eleven distinct flood basalt episodes occurred in the past 250 million years, creating volcanic provinces, which coincided with mass extinctions in prehistoric times. Formation depends on a range of factors, such as continental configuration, latitude, volume, rate, duration of eruption, style and setting (continental vs. oceanic), the preexisting climate state, and the biota resilience to change.