RSS 1.0Geology and Geophysics (G&G)
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Scientists in the G&G Department seek knowledge of the structure, composition, and dynamics of the earth’s interior, the origin and evolution of the earth’s crust, controls on ocean and climate change on time scales of decades to 100 million years, and processes of mass and energy transfer at the land-sea interface.
Recent Submissions
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Dissolved organic radiocarbon in the central Pacific Ocean
(American Geophysical Union, 2019-05-02)We report marine dissolved organic carbon (DOC) concentrations, and DOC ∆14C and δ13C values in seawater collected from the central Pacific. Surface ∆14C values are low in equatorial and polar regions where upwelling occurs ... -
Distribution of crustal melt bodies at the hot spot-influenced section of the Galapagos Spreading Centre from seismic reflection images
(American Geophysical Union, 2019-04-29)Accretion of the lower crust at mid‐ocean ridges is a debated topic, with modern seismic observations pointing to a complex magmatic system that includes an axial multisill system of middle‐ and lower‐crustal melt lenses ... -
Regional Pliocene exhumation of the Lesser Himalaya in the Indus drainage
(European Geosciences Union, 2019-05-16)New bulk sediment Sr and Nd isotope data, coupled with U–Pb dating of detrital zircon grains from sediment cored by the International Ocean Discovery Program in the Arabian Sea, allow the reconstruction of erosion in the ... -
The mighty Susquehanna-extreme floods in Eastern North America during the past two millennia
(American Geophysical Union, 2019-02-19)The hazards posed by infrequent major floods to communities along the Susquehanna River and the ecological health of Chesapeake Bay remain largely unconstrained due to the short length of streamgage records. Here we develop ... -
Big-picture geochemistry from microanalyses - my four-decade odyssey in sims
(European Association of Geochemistry, 2019-04)Secondary Ion Mass Spectrometry (SIMS) is now a well established analytical technique in geochemistry. Its developmental history goes back to the 1970s. Here, I tell the story of how I got involved in its applications to ... -
"Petit spot" rejuvenated volcanism superimposed on plume-derived Samoan shield volcanoes: Evidence from a 645-m drill core from Tutuila Island, American Samoa
(American Geophysical Union, 2019-02-13)In 2015 a geothermal exploration well was drilled on the island of Tutuila, American Samoa. The sample suite from the drill core provides 645 m of volcanic stratigraphy from a Samoan volcano, spanning 1.45 million years ... -
A comprehensive global oceanic dataset of helium isotope and tritium measurements.
(Copernicus Publications, 2019-04-05)Tritium and helium isotope data provide key information on ocean circulation, ventilation, and mixing, as well as the rates of biogeochemical processes and deep-ocean hydrothermal processes. We present here global oceanic ... -
Electrical investigation of natural lawsonite and application to subduction contexts
(American Geophysical Union, 2019-02-27)We report an experimental investigation of the electrical properties of natural polycrystalline lawsonite from Reed Station, CA. Lawsonite represents a particularly efficient water reservoir in subduction contexts, as it ... -
Azimuthal seismic anisotropy of 70-ma Pacific-plate upper mantle.
(American Geophysical Union, 2019-01-28)Plate formation and evolution processes are predicted to generate upper mantle seismic anisotropy and negative vertical velocity gradients in oceanic lithosphere. However, predictions for upper mantle seismic velocity ... -
Complex and diverse rupture processes of the 2018 Mw 8.2 and Mw 7.9 Tonga-Fiji deep earthquakes
(American Geophysical Union, 2019-02-20)Deep earthquakes exhibit strong variabilities in their rupture and aftershock characteristics, yet their physical failure mechanisms remain elusive. The 2018 Mw 8.2 and Mw 7.9 Tonga‐Fiji deep earthquakes, the two largest ... -
Fifty Years of Scientific Ocean Drilling
(Oceanography Society, 2019-03-16)Nearly a century after the first systematic study of the global ocean and seafloor by HMS Challenger (1871–1876), US scientists began to drill beneath the seafloor to unlock the secrets of the ~70% of Earth’s surface covered ... -
Contributions of scientific ocean drilling to under-standing the emplacement of submarine large igneous provinces and their effects on the environment.
(Oceanography Society, 2019-03-18)The Ontong Java Plateau (OJP), Shatsky Rise (SR), and Kerguelen Plateau/Broken Ridge (KP/BR) represent three large igneous provinces (LIPs) located in oceanic settings. The basement lavas have been investigated through ... -
What Lies Beneath: The formation and evolution of oceanic lithosphere
(Oceanography Society, 2019-03-18)Sampling the upper mantle via scientific ocean drilling remains elusive. Although the technologies required for drilling to the Moho still don’t exist, we have made significant progress over the last five decades in piecing ... -
Structure of the lithosphere beneath the Barotse Basin, western Zambia, from magnetotelluric data.
(American Geophysical Union, 2019-01-30)A magnetotelluric survey in the Barotse Basin of western Zambia shows clear evidence for thinned lithosphere beneath an orogenic belt. The uppermost asthenosphere, at a depth of 60–70 km, is highly conductive, suggestive ... -
Large spatial variations in the flux balance along the front of a Greenland tidewater glacier
(European Geosciences Union, 2019-03-15)The frontal flux balance of a medium-sized tidewater glacier in western Greenland in the summer is assessed by quantifying the individual components (ice flux, retreat, calving, and submarine melting) through a combination ... -
Fluid oscillations in a laboratory geyser with a bubble trap
(Elsevier, 2018-11-10)Geysers are rare geologic features that episodically erupt water and steam. While it is understood that the eruptions are triggered by the conversion of thermal to kinetic energy during decompression of hot uids, geysers ... -
High-resolution constraints on pacific upper mantle petrofabric inferred from surface-wave anisotropy.
(American Geophysical Union, 2018-12-26)Lithospheric seismic anisotropy illuminates mid‐ocean ridge dynamics and the thermal evolution of oceanic plates. We utilize short‐period (5–7.5 s) ambient‐noise surface waves and 15‐ to 150‐s Rayleigh waves measured across ... -
Petrocarbon evolution: Ramped pyrolysis/oxidation and isotopic studies of contaminated oil sediments from the Deepwater Horizon oil spill in the Gulf of Mexico.
(Public Library of Science, 2019-02-28)Hydrocarbons released during the Deepwater Horizon (DWH) oil spill weathered due to exposure to oxygen, light, and microbes. During weathering, the hydrocarbons’ reactivity and lability was altered, but it remained ... -
Fungi in the Marine Environment: Open Questions and Unsolved Problems
(American Society for Microbiology, 2019-03-05)Terrestrial fungi play critical roles in nutrient cycling and food webs and can shape macroorganism communities as parasites and mutualists. Although estimates for the number of fungal species on the planet range from 1.5 ... -
Emplacement and high-temperature evolution of gabbros of the 16.5 degrees N oceanic core complexes (Mid-Atlantic Ridge): Insights into the compositional variability of the lower oceanic crust.
(American Geophysical Union, 2018-12-05)This study reports the composition of the oceanic crust from the 16.5°N region of the Mid‐Atlantic Ridge, a spreading ridge segment characterized by a complex detachment fault system and three main oceanic core complexes ...
