as a PDF
... sedimentary rocks including banded iron formations (BIFs) and ferruginous/siliceous mudstone from the Cleaverville area in the Pilbara craton, Western Australia. Geological, lithological, and geochemical lines of evidence indicate that these sedimentary rocks preserve a continuous record of depositi ...
... sedimentary rocks including banded iron formations (BIFs) and ferruginous/siliceous mudstone from the Cleaverville area in the Pilbara craton, Western Australia. Geological, lithological, and geochemical lines of evidence indicate that these sedimentary rocks preserve a continuous record of depositi ...
Mantle-like Trace Element Composition of Petroleum
... individual trace elements, differences in trace element compositions among basins of different tectonic and sedimentary settings, and the effect of thermal cracking related to igneous activity. Studies of this kind, covering a wide range of trace metals in petroleum and their regional distribution o ...
... individual trace elements, differences in trace element compositions among basins of different tectonic and sedimentary settings, and the effect of thermal cracking related to igneous activity. Studies of this kind, covering a wide range of trace metals in petroleum and their regional distribution o ...
Influence of continental roots and asthenosphere on plate
... proportional to the square root of lithospheric age [Müller et al., 1997]. For the continents, we followed Gung et al. [2003], who used the maximum depth for which the velocity anomaly (from S20RTSb) is consistently greater than +2% to estimate continental thickness at any given location. We impose ...
... proportional to the square root of lithospheric age [Müller et al., 1997]. For the continents, we followed Gung et al. [2003], who used the maximum depth for which the velocity anomaly (from S20RTSb) is consistently greater than +2% to estimate continental thickness at any given location. We impose ...
Unconventional Isotopes and Approaches
... chondrites is also statistically significant and could also not result from equilibrium fractionation during core formation. It is possible, however, that some as yet unrecognized form of kinetic fractionation could account for the difference; if so that could provide clues to the details of the cor ...
... chondrites is also statistically significant and could also not result from equilibrium fractionation during core formation. It is possible, however, that some as yet unrecognized form of kinetic fractionation could account for the difference; if so that could provide clues to the details of the cor ...
OBSERVATIONAL AND THEORETICAL STUDIES OF THE DYNAMICS OF MANTLE PLUME–MID-OCEAN RIDGE INTERACTION
... islands. Positive is anomalously shallow, and negative is anomalously deep. Original bathymetry is a global grid derived from shipboard soundings and satellite altimetry [Smith and Sandwell, 1997]. We corrected for the thickness and loading effects of sediments using the sediment thickness and densi ...
... islands. Positive is anomalously shallow, and negative is anomalously deep. Original bathymetry is a global grid derived from shipboard soundings and satellite altimetry [Smith and Sandwell, 1997]. We corrected for the thickness and loading effects of sediments using the sediment thickness and densi ...
Multiple sulfur isotope composition of oxidized Samoan melts and
... No clear trend appears between δ 34 S and S abundance, or between δ 34 S and S speciation (Table S1). Instead, the δ 34 S values of reduced sulfur are correlated with source enrichment proxies such as 87 Sr/86 Sr (Fig. 6), with the exception of two glasses: 79-4 and 73-12. The former is the most evo ...
... No clear trend appears between δ 34 S and S abundance, or between δ 34 S and S speciation (Table S1). Instead, the δ 34 S values of reduced sulfur are correlated with source enrichment proxies such as 87 Sr/86 Sr (Fig. 6), with the exception of two glasses: 79-4 and 73-12. The former is the most evo ...
Geophysical assessment of migration and storage conditions of
... different seismic observables, a reduction in seismic velocities and quality factor Q can be used to infer fluidbearing regions at depth and define fluid pathways (e.g., Syracuse et al. 2008; Rychert et al. 2008). In particular, seismic wave attenuation (Q−1) and Poisson's ratio (Vp/Vs) are sensitiv ...
... different seismic observables, a reduction in seismic velocities and quality factor Q can be used to infer fluidbearing regions at depth and define fluid pathways (e.g., Syracuse et al. 2008; Rychert et al. 2008). In particular, seismic wave attenuation (Q−1) and Poisson's ratio (Vp/Vs) are sensitiv ...
Origin of the Bermuda volcanoes and Bermuda
... plateau in the early Miocene—thus indicating that net post-volcanic subsidence has been negligible, averaging only about .004 mm/a. At least under parts of Bermuda, the sequence of limestones and interglacial soils is underlain by a lateritic clay horizon (“Primary Red Clay”) derived from subaerial ...
... plateau in the early Miocene—thus indicating that net post-volcanic subsidence has been negligible, averaging only about .004 mm/a. At least under parts of Bermuda, the sequence of limestones and interglacial soils is underlain by a lateritic clay horizon (“Primary Red Clay”) derived from subaerial ...
pdf file - University of Victoria
... upper mantle. The Moho boundary relaxes to a nearly-horizontal gravitational equipotential over ...
... upper mantle. The Moho boundary relaxes to a nearly-horizontal gravitational equipotential over ...
Carbon Retention in Deeply Subducted Sedimentary Rocks
... shown for context. ...............................................................................................62 Appendix 6. Comparison of observed bulk δ13C values with values predicted for a closed-system model, where isotope ratios are controlled by exchange within the system rather than by e ...
... shown for context. ...............................................................................................62 Appendix 6. Comparison of observed bulk δ13C values with values predicted for a closed-system model, where isotope ratios are controlled by exchange within the system rather than by e ...
Controls on back-arc basin formation
... [1] The relationship between subduction and back-arc spreading has been well known since the early days of plate tectonics. However, the reasons why back-arc basins are associated with some subduction systems but not all has remained elusive. We examine the kinematic controls on subduction and back- ...
... [1] The relationship between subduction and back-arc spreading has been well known since the early days of plate tectonics. However, the reasons why back-arc basins are associated with some subduction systems but not all has remained elusive. We examine the kinematic controls on subduction and back- ...
Eduard Suess` conception of the Alpine orogeny related to
... In his treatise „Die Entstehung der Alpen“, Eduard Suess presents a wealth of geological observations and a fascinating conception of the orogeny of the Alps and mountain chains in general. It is an inspiring task to review the state of the Physics of the Earth at the time when Suess worked on this ...
... In his treatise „Die Entstehung der Alpen“, Eduard Suess presents a wealth of geological observations and a fascinating conception of the orogeny of the Alps and mountain chains in general. It is an inspiring task to review the state of the Physics of the Earth at the time when Suess worked on this ...
Roberts et al., 2013, Basin Modeling
... The gravity inversion methodology and workflow is summarized in Figure 1a (adapted from Alvey 2010). Key to the success of the gravity inversion method are two geological corrections, made in order to account for the highly attenuated nature of the continental crust at rifted margins. The two correc ...
... The gravity inversion methodology and workflow is summarized in Figure 1a (adapted from Alvey 2010). Key to the success of the gravity inversion method are two geological corrections, made in order to account for the highly attenuated nature of the continental crust at rifted margins. The two correc ...
Mapping and Monitoring Large-Scale Ocean Fronts Off the
... who may have a need for it. Also, because ocean fronts change in time and space and since we cannot predict their behavior in detail, monitoring ocean fronts from space on a regular basis should benefit the marine community, including a number of agencies. The National Marine Fisheries Service (NMFS) ...
... who may have a need for it. Also, because ocean fronts change in time and space and since we cannot predict their behavior in detail, monitoring ocean fronts from space on a regular basis should benefit the marine community, including a number of agencies. The National Marine Fisheries Service (NMFS) ...
Niu, Y., Generation and evolution of basaltic magmas
... explains the occurrences and distributions earthquakes and voluminous volcanic eruptions along plate boundaries: (1) at seafloor spreading centers where two plates pull apart, the ocean crust is being continuously created by volcanism; (2) at convergent boundaries where the oceanic plate returns int ...
... explains the occurrences and distributions earthquakes and voluminous volcanic eruptions along plate boundaries: (1) at seafloor spreading centers where two plates pull apart, the ocean crust is being continuously created by volcanism; (2) at convergent boundaries where the oceanic plate returns int ...
Rare earth elements and neodymium isotopes in sedimentary
... present in natural waters are generally derived from photosynthetic processes, with the exception of deep-sea extreme environments, such as submarine hydrothermal systems and methane seeps, where organic biomass can be produced by chemosynthesis. A significant fraction of particulate OM in seawater ...
... present in natural waters are generally derived from photosynthetic processes, with the exception of deep-sea extreme environments, such as submarine hydrothermal systems and methane seeps, where organic biomass can be produced by chemosynthesis. A significant fraction of particulate OM in seawater ...
phosphorus recycling in brackish and marine environments
... the North Sea. Introduction of sewage treatment plants in major cities in the 1960’s and further improvements of these in the 70’s and 80’s decreased the phosphorus and later nitrogen loads to the waters. Despite the decreased loads to the Baltic Sea the water quality did not improve. Recently, this ...
... the North Sea. Introduction of sewage treatment plants in major cities in the 1960’s and further improvements of these in the 70’s and 80’s decreased the phosphorus and later nitrogen loads to the waters. Despite the decreased loads to the Baltic Sea the water quality did not improve. Recently, this ...
Tracing the evolving flux from the subducting plate in the Tonga
... melting of a mid ocean ridge system. In most subduction systems the arc volcanic front is located over the dewatering slab at around 100 km depth (Tatsumi et al., 1983). The fluid and amphibole, generated by hydration of the mantle wedge above a subducting oceanic plate, is carried down and under th ...
... melting of a mid ocean ridge system. In most subduction systems the arc volcanic front is located over the dewatering slab at around 100 km depth (Tatsumi et al., 1983). The fluid and amphibole, generated by hydration of the mantle wedge above a subducting oceanic plate, is carried down and under th ...
PDF (Chapter 9. The Source Region)
... various degrees of partial melting, up to about 20 percent, of a garnet peridotite source region is based on several lines of evidence and assumptions (Yoder, 1976). Peridotites are a common rock type and are found as xenoliths in kimberlite and magma, in obducted sections of oceanic lithosphere and ...
... various degrees of partial melting, up to about 20 percent, of a garnet peridotite source region is based on several lines of evidence and assumptions (Yoder, 1976). Peridotites are a common rock type and are found as xenoliths in kimberlite and magma, in obducted sections of oceanic lithosphere and ...
Spontaneous development of arcuate single‐sided subduction in
... drivers of mantle convection and plate tectonics [Forsyth and Uyeda, 1975; Conrad and Lithgow-Bertelloni, 2002]. Dynamical implications of subduction zones are, however, not only limited to plate velocities but find also expression in the strongly time-dependent, strongly three-dimensional flow of sla ...
... drivers of mantle convection and plate tectonics [Forsyth and Uyeda, 1975; Conrad and Lithgow-Bertelloni, 2002]. Dynamical implications of subduction zones are, however, not only limited to plate velocities but find also expression in the strongly time-dependent, strongly three-dimensional flow of sla ...
Noble Gas Constraints on Mantle Structure and Convection
... Important questions that need to be answered • Are the noble gases really more incompatible than their radioactive parents U, Th, and K during partial melting? Can the noble gases be partitioned into the core? • What physical mechanism(s) control gas loss during mid ocean ridge and ocean island vol ...
... Important questions that need to be answered • Are the noble gases really more incompatible than their radioactive parents U, Th, and K during partial melting? Can the noble gases be partitioned into the core? • What physical mechanism(s) control gas loss during mid ocean ridge and ocean island vol ...
Response to EPA Notice of Call for Public Comment on 303(d) Program and Ocean Acidification from the Ocean Carbon and
... Industrial Revolution has increased atmospheric CO2 concentrations from a stable baseline of approximately 280 parts per million (ppm) to the present level of 387 ppm. The atmospheric concentration of CO2 is now higher than experienced on Earth for at least the last 800,000 years, and its level and ...
... Industrial Revolution has increased atmospheric CO2 concentrations from a stable baseline of approximately 280 parts per million (ppm) to the present level of 387 ppm. The atmospheric concentration of CO2 is now higher than experienced on Earth for at least the last 800,000 years, and its level and ...
Flow and melting of a heterogeneous mantle: 2. Implications for a
... large-scale layering. In this study, we test this possibility by solving for the mantle source compositions that, when melted in a hot plume beneath lithosphere of appropriate thickness, can explain key geochemical correlations at specific hotspots. Both the age of the seafloor at the time of volcan ...
... large-scale layering. In this study, we test this possibility by solving for the mantle source compositions that, when melted in a hot plume beneath lithosphere of appropriate thickness, can explain key geochemical correlations at specific hotspots. Both the age of the seafloor at the time of volcan ...
Lithium Isotope Variations in Ocean Island
... melting, and thus concentrated in the crust relative to the mantle. Lithium is mobile in aqueous fluids and has two stable isotopes, 6Li and 7Li, that are, unlike the radiogenic Sr^Nd^Pb isotope systems, unaffected by time-dependent parent^daughter fractionation processes. The preferential loss of 7 ...
... melting, and thus concentrated in the crust relative to the mantle. Lithium is mobile in aqueous fluids and has two stable isotopes, 6Li and 7Li, that are, unlike the radiogenic Sr^Nd^Pb isotope systems, unaffected by time-dependent parent^daughter fractionation processes. The preferential loss of 7 ...
Sulfur and oxygen isotope insights into sulfur cycling in shallow
... often produce shallow-sea vent systems, and their geochemical cycles can differ demonstrably from those found in mid-ocean ridges. Compared to deep-sea hydrothermal systems, the shallow-sea varieties are generally cooler (<150°C), are under lower hydrostatic pressure (<21.1 bar by definition), and c ...
... often produce shallow-sea vent systems, and their geochemical cycles can differ demonstrably from those found in mid-ocean ridges. Compared to deep-sea hydrothermal systems, the shallow-sea varieties are generally cooler (<150°C), are under lower hydrostatic pressure (<21.1 bar by definition), and c ...
Abyssal plain
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface. They are among the flattest, smoothest and least explored regions on Earth. Abyssal plains are key geologic elements of oceanic basins (the other elements being an elevated mid-ocean ridge and flanking abyssal hills). In addition to these elements, active oceanic basins (those that are associated with a moving plate tectonic boundary) also typically include an oceanic trench and a subduction zone.Abyssal plains were not recognized as distinct physiographic features of the sea floor until the late 1940s and, until very recently, none had been studied on a systematic basis. They are poorly preserved in the sedimentary record, because they tend to be consumed by the subduction process. The creation of the abyssal plain is the end result of spreading of the seafloor (plate tectonics) and melting of the lower oceanic crust. Magma rises from above the asthenosphere (a layer of the upper mantle) and as this basaltic material reaches the surface at mid-ocean ridges it forms new oceanic crust. This is constantly pulled sideways by spreading of the seafloor. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. Much of this sediment is deposited by turbidity currents that have been channelled from the continental margins along submarine canyons down into deeper water. The remainder of the sediment is composed chiefly of pelagic sediments. Metallic nodules are common in some areas of the plains, with varying concentrations of metals, including manganese, iron, nickel, cobalt, and copper. These nodules may provide a significant resource for future mining ventures.Owing in part to their vast size, abyssal plains are currently believed to be a major reservoir of biodiversity. The abyss also exerts significant influence upon ocean carbon cycling, dissolution of calcium carbonate, and atmospheric CO2 concentrations over timescales of 100–1000 years. The structure and function of abyssal ecosystems are strongly influenced by the rate of flux of food to the seafloor and the composition of the material that settles. Factors such as climate change, fishing practices, and ocean fertilization are expected to have a substantial effect on patterns of primary production in the euphotic zone. This will undoubtedly impact the flux of organic material to the abyss in a similar manner and thus have a profound effect on the structure, function and diversity of abyssal ecosystems.