نتایج جستجو برای: sedimentary environment
تعداد نتایج: 527372 فیلتر نتایج به سال:
Seamounts and their influence on the surrounding environment are currently being extensively debated but, surprisingly, scant information is available for the Mediterranean area. Furthermore, although the deep Tyrrhenian Sea is characterised by a complex bottom morphology and peculiar hydrodynamic features, which would suggest a variable influence on the benthic domain, few studies have been ca...
The diversity of microorganisms active within sedimentary rocks provides important controls on the geochemistry of many subsurface environments. In particular, biodegradation of organic matter in sedimentary rocks contributes to the biogeochemical cycling of carbon and other elements and strongly impacts the recovery and quality of fossil fuel resources. In this study, archaeal diversity was in...
Raman spectra of carbonaceous materials in one of the world’s oldest sedimentary rock formations – the Strelley Pool Chert (Pilbara Craton, Western Australia) – are analysed to determine whether primary structural characteristics of organic molecules may have survived to the present day. We use Raman spectral parameters to identify variations in molecular structure of the carbon and determine w...
a r t i c l e i n f o a b s t r a c t Rock alteration and rind formation in analog environments like Antarctica may provide clues to rock alteration and therefore paleoclimates on Mars. Clastic sedimentary rocks derived from basaltic sources have been studied in situ by martian rovers and are likely abundant on the surface of Mars. However, how such rock types undergo alteration when exposed to...
Mineralogy studies by NASA Opportunity Rover report iron oxides and hydroxides precipitates on Endurance Crater. Sedimentary deposits have been identify at Meridiani Planum [2]. This deposits should had generated in a dune aqueous acidic and oxidizing environment. Similarities appear when we study Rio Tinto, and acidic river under the control of iron [3]. We will focus on two principal Mars Ana...
Widespread sedimentary rocks on Mars preserve evidence of surface conditions different from the modern cold and dry environment, although it is unknown how long conditions favorable to deposition persisted. We used 1-meter stereo topographic maps to demonstrate the presence of rhythmic bedding at several outcrops in the Arabia Terra region. Repeating beds are approximately 10 meters thick, and ...
Recent simulations of diffusion limited cluster-cluster aggregation (DLCA) have shown systematic inhomogeneities in the shape and orientation of clusters formed when a sedimentary force is applied. Using custom simulation and visualisation techniques and programs we have carried out a microscopic study of these sedimentary inhomogeneities and have mapped out the model parameter space. We find v...
by intermittent land masses on the northeast and southwest. The area has been cut by numerous right-lateral transcurrent faults and the stratified rocks now lie along the northeastern flank of the Coast Plutonic Complex. leletzky and Tipper (1968) described a faunal stratigraphy for the Taseko Lakes map sheet and discussed the role of the Qaughton trough in the geological history of southwester...
As pointed out in the introduction to this book, shales contain the lion’s share of earth history that is recorded in sedimentary rocks. Understanding their deposition is key to the reconstruction of past oceans, landscapes, climates, and climatic cycles. Yet, whereas students of sandstones and carbonates have been able to learn a great deal about the deposition of these rocks from studying bed...
1. Vegetated biogeomorphic systems (e.g. mangroves, salt marshes, dunes, riparian vegetation) have been intensively studied for the impact of the biota on sediment transport processes and the resulting self-organization of such landscapes. However, there is a lack of understanding of physical disturbance mechanisms that limit primary colonization in active sedimentary environments. 2. This stud...
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