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Coastal cliff erosion is alongshore-variable and episodic, with retreat rates that depend upon sediment as either tools of abrasion or protective cover. However, the feedbacks between coastal cliff planform morphology, retreat rate, and sediment cover are poorly quantified. This study investigates Sargent Beach, Texas, USA, at the annual to interannual scale to explore (1) the relationship between temporal and spatial variability in cliff retreat rate, roughness, and sinuosity and (2) the response of retreat rate and roughness to changes in sand and shell hash cover of the underlying mud substrate as well as the impact of major storms using field measurements of sediment cover, erosion, and aerial images to measure shore platform morphology and retreat. A storm event in 2009 increased the planform roughness and sinuosity of the coastal cliff at Sargent Beach. Following the storm, aerial-image-derived shorelines with annual resolution show a decrease in average alongshore erosion rates from 12 to 4 m yr−1, coincident with a decrease in shoreline roughness and sinuosity (smoothing). Like the previous storm, a storm event in 2017 increased the planform roughness and sinuosity of the cliff. Over shorter timescales, monthly retreat of the sea cliff occurred only when the platform was sparsely covered with sediment cover on the shore platform, indicating that the tools and cover effects can significantly affect short-term erosion rates. The timescale to return to a smooth shoreline following a storm or roughening event, given a steady-state erosion rate, is approximately 24 years, with the long-term rate suggesting a maximum of ∼107 years until Sargent Beach breaches, compromising the Gulf Intracoastal Waterway (GIWW) under current conditions and assuming no future storms or intervention. The observed retreat rate varies, both spatially and temporally, with cliff face morphology, demonstrating the importance of multi-scale measurements and analysis for interpretation of c, National Science Foundation (Grant 1745302)

On the base of analysis of data from different seismic bulletins for the Japan Sea basin the most comprehensive unified catalogue of earthquake with magnitude M > 3,0 and depths h < 60 km for the period 1975-2010 has been prepared for the first time. Maps of epicenter of events for the four intervals (0-10, 11-20, 21-30 and 31-60 km) and three sub-latitude sections are plotted. Structural peculiarities have been considered and possible tectonic nature of seismic zone along submarine margin or borderland of the Japan-Sakhalin island arc: regional uplift, rather mega-duplex fracture of compression faults, caused by crustal sliding at the rear of frontal deep thrust.

Thesis: Ph. D. in Marine Geology, Joint Program in Marine Geology and Geophysics (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2017., Cataloged from PDF version of thesis., Includes bibliographical references., This thesis analyzes compositions of seafloor massive sulfide (SMS) deposits and related hydrothermal vent fluids to identify proxies of reaction zone conditions (host-rock lithology, hydrothermal fluid temperature and chemistry). Chapter 2 investigates the morphology, mineralogy, and geochemistry of SMS deposits from six vent fields along the Eastern Lau Spreading Center (ELSC), demonstrating that ELSC SMS deposits record differences in hydrothermal fluid temperature, pH, sulfur fugacity and host-rock lithology related to proximity to the nearby Tonga Subduction Zone. Chapters 3 and 4 focus on partitioning of Co, Ni, Ga, Ag, and In between hydrothermal vent fluids and chalcopyrite lining fluid conduits in black smoker chimneys. Chapter 3 develops secondary ion mass spectrometry (SIMS) as a technique to measure Co, Ni, Ga, Ag, and In in chalcopyrite and identifies a correlation between Ga and In in chalcopyrite and hydrothermal fluid pH. Chapter 4 presents new data on these elements in ELSC hydrothermal fluids that, combined with SIMS analyses of chalcopyrite chimney linings and previously published data on vent fluids from the Manus Basin, provide evidence that supports partitioning of Ag a lattice substitution for Cu. Together, concentrations of Ga, In, and Ag in chalcopyrite provide proxies of hydrothermal fluid pH and metal (i.e., Ag and Cu) contents., by Guy Nathaniel Evans., Ph. D. in Marine Geology

type:Journal Article, Absorption, scattering, and color distortion are three major degradation factors in underwater optical imaging. Light rays are absorbed while passing through water, and absorption rates depend on the wavelength of the light. Scattering is caused by large suspended particles, which are always observed in an underwater environment. Color distortion occurs because the attenuation ratio is inversely proportional to the wavelength of light when light passes through a unit length in water. Consequently, underwater images are dark, low contrast, and dominated by a bluish tone. In this paper, we propose a novel underwater imaging model that compensates for the attenuation discrepancy along the propagation path. In addition, we develop a robust color lines-based ambient light estimator and a locally adaptive filtering algorithm for enhancing underwater images in shallow oceans. Furthermore, we propose a spectral characteristic-based color correction algorithm to recover the distorted color. The enhanced images have a reasonable noise level after the illumination compensation in the dark regions, and demonstrate an improved global contrast by which the finest details and edges are enhanced significantly.

Thesis: Ph. D. in Geochemistry, Joint Program in Marine Geology and Geophysics (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2016., "February 2016." Cataloged from PDF version of thesis., Includes bibliographical references., Fractional crystallization of mantle-derived basaltic melts is a critical process in producing a compositionally stratified continental crust characterized by a silicic upper crust and a mafic lower crust. This thesis explores outstanding questions associated with fractional crystallization through detailed field, petrological, and geochemical studies of the Dariv Igneous Complex in Western Mongolia. The Dariv Igneous Complex records the crystallization of a high-K primitive arc melt at shallow crustal levels, preserving both biotite-bearing ultramafic and mafic cumulates, as well as liquid-like evolved plutonics, such as (quartz-)monzonites. Chapter 2 presents comprehensive field and petrographic descriptions of the complex and establishes the petrogenetic groundwork to understand the conditions under which it formed. Results of this study indicate that the observed lithologies formed through the fractional crystallization of a high-K hydrous basalt, typical of alkali-rich basalts found in subduction zone settings, at 0.2-0.5 GPa and elevated oxygen fugacities. Chapter 3 presents a quantitatively modeled liquid line of descent (LLD) for the complex based on whole rock geochemical analyses, which is able to explain the trends observed in the monzonitic plutonic series observed in continental arcs. The oxygen isotope trajectory of fractionally crystallizing melts is rigorously constrained through modeling and mineral analyses in Chapter 4. This study indicates that large (1 to 1.8%o) increases in [delta]18O as a melt evolves from basaltic to granitic in composition due to the fractionation of low [delta]18O minerals. As such, the majority of [delta]180 values of upper crustal silicic plutonics can be explained through fractional crystallization of primitive arc basalts alone without needing to invoke assimilation of high [delta]18O crustal material. Finally, Chapter 5 explores the timescales associated with fractional crystallization through high precision U-Pb geoch, by Claire Elizabeth Bucholz., Ph. D. in Geochemistry

Oil and gas perspective Mesozoic complex in Dnieper-Donets depression includes Triassic, Jurassic and Lower part of Cretaceous systems. Its common thickness can reach one kilometer and much more. The deposit complex widely spread in Preaxial and Northern near-edge zones of Depression. Geologic and log data about potential Triassic and Jurassic rocks hydrocarbons bearing on several of tens local structures, not including here already known Mesozoic fields, there exist missed productive layers and even stratigraphic complexes, point on exclusive interesting character of this exploration direction. The fact is strange and hardly explainable, but since 1960s years systematic study of Mesozoic rocks in Eastern Ukraine has not been executed. Meanwhile, there are no theoretic foundations which contradict to possibility of Mesozoic commercial hydrocarbon pools forming on most part of Eastern Ukrainian oil and gas bearing basin territory, on the contrary, most of its uplifts have favourable genetic, migrational and accumulative terms of Triassic, Jurassic, and probably Cretaceous hydrocarbon pools existence. Triassic and Jurassic systems deposits of DDD characterized by small and middle bedding depth, freandly thermic, pressure and hydrogeochemical environment. Perspective folds and uplifts mostly sityated in areas with convenient search and development infrastructure. Rational searching complex of works, directed on Mesozoic pools discovery and commercial exploitation proposed., Перспективный мезозойский комплекс ДДВ включает отложения триаса, юры и раннего мела. Данные про потенциальную нефтегазоносность триаса и юры на нескольких десятках локальных структур, не считая известных мезозойских месторождений, на которых есть пропущенные перспективные пласты и целые стратиграфические комплексы, говорят про исключительный интерес этого направления исследований. Теоретических оснований, которые противоречили бы возможности формирования промышленных скоплений углеводородов в мезозое на преобладающей части территории Восточно-Украинского НГБ не существует, напротив, на большей части его структур присутствуют благоприятные генетические, миграционные и аккумулятивные условия существования триасовых, юрских и, возмоно, - меловых скоплений нефти и газа. Для прогнозных залежей триасовой і юрской системы ДДВ характерны небольшие и средние глубины залегания,благоприятные термобарические и гидрогеохимические обстановки. Предложен рациональный комплекс работ по выявлению мезозойских залежей и вовлечению их в промысловую разработку., Перспективний мезозойський комплекс ДДЗ включає відклади тріасу, юри і ранньої крейди. Дані про потенційну нафтогазоносність тріасу і юри на декількох десятках локальних структур, не рахуючи відомих мезозойських родовищ, на яких є пропущені перспективні пласти і цілі стратиграфічні комплекси, говорять про виключну цікавість цього напрямку досліджень. Теоретичних передумов, які заперечують можливість формування промислових скупчень вуглеводнів в мезозої на більшій частині території Східно-Українського НГБ не існує, навпаки, на переважній більшості його структур присутні сприятливі генетичні, міграційні і акумуляційні умови існування тріасових, юрських і, можливо, - крейдових скупчень нафти і газу. Для прогнозних покладів тріасової і юрської систем ДДЗ характерні невеликі і середні глибини залягання, сприятливі термобаричні і гідрогеохімічні умови. Пропонується раціональний комплекс робіт по виявленню мезозойських покладів і залученню їх в промислову розробку.