Polygene Konglomerate im nordalpinen Rhät und die altkimmerische Phase

Ohne Zusammenfassung     

Das Pamir-System

Ohne Zusammenfassung     

Crooked line, rough topography: advancing towards the correct seismic image

Seismic exploration in mountainous areas imposes serious compromises on both acquisition and processing. Access restrictions usually result in profiles that are not straight and are not recorded along the true dip direction (if there is a true dip direction!). Processing constraints often result in very poor approximate corrections for elevations and for deviations from a straight line. Most fundamentally, 2D acquisition and processing assumes that the earth is 2D; this assumption is often seriously violated in mountainous areas. While we cannot efficiently correct 2D seismic data for the effects of a fully 3D subsurface, we can improve the data quality in thrust areas where the assumption of 2D subsurface variation is reasonable. We do this in a series of small steps, which improves the accuracy of several approximations made in processing 2D land data.     

Calibration of a Land Subsidence Model Using InSAR Data via the Ensemble Kalman Filter

The application of interferometric synthetic aperture radar (InSAR) has been increasingly used to improve capabilities to model land subsidence in hydrogeologic studies. A number of investigations over the last decade show how spatially detailed time‐lapse images of ground displacements could be utilized to advance our understanding for better predictions. In this work, we use simulated land subsidences as observed measurements, mimicking InSAR data to inversely infer inelastic specific storage in a stochastic framework. The inelastic specific storage is assumed as a random variable and modeled using a geostatistical method such that the detailed variations in space could be represented and also that the uncertainties of both characterization of specific storage and prediction of land subsidence can be assessed. The ensemble Kalman filter (EnKF), a real‐time data assimilation algorithm, is used to inversely calibrate a land subsidence model by matching simulated subsidences with InSAR data. The performance of the EnKF is demonstrated in a synthetic example in which simulated surface deformations using a reference field are assumed as InSAR data for inverse modeling. The results indicate: (1) the EnKF can be used successfully to calibrate a land subsidence model with InSAR data; the estimation of inelastic specific storage is improved, and uncertainty of prediction is reduced, when all the data are accounted for; and (2) if the same ensemble is used to estimate Kalman gain, the analysis errors could cause filter divergence; thus, it is essential to include localization in the EnKF for InSAR data assimilation.     

Reconstruction of fluvio-lacustrine landscapes and settlement history in the Texcoco region,Mexico, using a modern geomorphic analog

Located in the Basin of Mexico, the eastern shore of former Lake Texcoco sustained a variety of human occupations throughout the Holocene, including preceramic hunter-gatherers, incipient agriculturalists, and a variety of settlements in the ceramic periods. Nonetheless, the environmental dynamics of occupations on the lakeshore have not been fully addressed. The Archaic preagricultural Texcoco Man site (>5000 B.C.E.) and the Late Formative TX-LF-14 site (c. 550-200 B.C.E.), among others, occupy this fluvio-lacustrine transitional environment. Few stratigraphic works in and around the sites have been performed. Consequently, it is difficult to understand the dynamics of the sedimentary system in space and time. This work highlights and describes the fluvio-lacustrine sedimentary dynamics and the resulting landscape that past societies inhabited on the eastern shore of Texcoco Lake. Because the study area has been altered by historic and modern draining, our work employs Lake Santiaguillo and its main tributary, the Tejamen River in the Durango state, as a modern analog to study their sedimentary dynamics. The analyses of surface geomorphology in the Texcoco study area were employed to corroborate the modern analog interpretation. To achieve these goals, we conducted a GIS-based morphometric analysis and LANDSAT-8 imagery to study the variations in landforms through wet and dry events. The results indicate an increase in the lake volume, low bifurcation in the active fluvial channels, few inundated surfaces, and the presence of bird-foot deltaic channels during high precipitation events. In contrast, low precipitation events are characterized by reduced lake volume, increased fluvial channel bifurcation, and expanded floodplains. This heterogeneous landscape thus provided a rich source of diverse natural resources of saline and freshwater aquatic habitats. Simultaneously, constant or recurring flooding events generated a challenging landscape for prehistoric settlers who implemented diverse technologies, such as the construction of tlateles, on the levees of deltaic channels to reduce the risk and impact of flooding events.     

Deep-sea faunal communities associated with a lost intermodal shipping container in the Monterey Bay National Marine Sanctuary,CA

Carrying assorted cargo and covered with paints of varying toxicity, lost intermodal containers may take centuries to degrade on the deep seafloor. In June 2004, scientists from Monterey Bay Aquarium Research Institute (MBARI) discovered a recently lost container during a Remotely Operated Vehicle (ROV) dive on a sediment-covered seabed at 1281 m depth in Monterey Bay National Marine Sanctuary (MBNMS). The site was revisited by ROV in March 2011. Analyses of sediment samples and high-definition video indicate that faunal assemblages on the container’s exterior and the seabed within 10 m of the container differed significantly from those up to 500 m. The container surface provides hard substratum for colonization by taxa typically found in rocky habitats. However, some key taxa that dominate rocky areas were absent or rare on the container, perhaps related to its potential toxicity or limited time for colonization and growth. Ecological effects appear to be restricted to the container surface and the benthos within ∼10 m.     

Cladocora caespitosa bioconstructions in the Columbretes Islands Marine Reserve (Spain,NW Mediterranean): distribution,size structure and growth

Today, living banks of the coral Cladocora caespitosa appear to be restricted to a few Mediterranean locations and are threatened by the escalating impacts affecting coastal areas. In this study the exceptional occurrence of the Mediterranean coral C. caespitosa in the Columbretes Islands Marine Reserve (NW Mediterranean, Spain) is characterised in terms of spatial distribution, cover area, colony size and growth rates. The coral colonies form beds and banks in rocky bottoms within a semi‐enclosed bay that offers both hydrodynamic protection and high water exchange. The spatial distribution of the C. caespitosa colonies, from 5 to 27 m depth, is highly aggregated, depending on sea‐floor morphology and showing up to 80% of substrate coverage. The annual corallite growth rates obtained through the alizarin red staining method and x‐ray image analysis are similar, and range between 2.55 ± 0.79 mm and 2.54 ± 0.81 mm, respectively. The exceptional nature of these bioconstructions is due to their cumulative cover area, which is comparable in size to the largest C. caespitosa bioconstructions described to date in Mljet National Park (Croatia, Adriatic Sea).