Sedimentary processes in Lake Van: first results from a joint interpretation of seismic and drilling data

EGU2011-1847-3 Lake Van is a lake by volume of 607 km3 and a maximum depth of 450 meters in a tectonically active zone in eastern Anatolia, Turkey. In summer 2010, Lake Van was the target of a deep drilling campaign (PaleoVan) in the frame of ICDP (International Continental Scientific Drilling Program). Two sites were drilled based on reflection seismic data collected during a seismic campaign in 2004. Here we present a first joint interpretation of the seismic and drilling data. Interpretation of seismic reflection data from lake reveals three physiographic provinces: a lacustrine shelf, a lacustrine slope, and a deep, relatively flat lake basin. The most prominent features of the lacustrine shelf and slope are prograding deltaic sequences, numerous unconformities, submerged channels, as well as closely spaced U- and/or V-shaped depressions, reflecting the variable lake level history of Lake Van. The seismic units of the shelf are dominantly composed of low-to-good continuity, variable amplitude reflections interpreted as fluvial deposits. The lake consists of three prominent basins (Tatvan, Deveboynu, and Northern Basins), separated by basement highs or ridges (Ahlat Ridge). The seismic units corresponding to these basins mainly consist of low to very high amplitude, well-stratified reflection patterns. Chaotic reflections are seen in parts of these basins. The Deveboynu Basin consists mainly of chaotic reflections. The Tatvan and Northern Basins are characterized by an alternating succession of well-stratified and chaotic reflecting layers. The chaotic seismic facies are interpreted as slump and slide deposits, which are probably the result of quick lake level fluctuations and/or earthquakes. The moderateto high amplitude, well-stratified facies seen in the deep parts of the basins away from the terrigenous sediment sources are interpreted as lacustrine deposits and tephra layers. The total sediment thickness in the deep parts of the lake is over 400 m. Prominent clinoforms indicate the initial flooding of Lake Van about 500 ka ago. The acoustic basement and the sediments lying on top of the basement in the southern part of the lake are disrupted by various intrusions and extrusions suggesting active volcanism. Synthetic seismograms calculated based on core logging, wire-line logging and check shot data will allow the correlation between seismic and drill data. This approach will allow extrapolating the stratigraphy from the wells to 3D-space by using the seismic data

Das Quartär als chronostratigraphische Einheit

Das Quartär als System – traditionell als Eiszeitalter aufgefasst – ist ein Intervall, das durch wechselnde klimatische Extreme (Kalt- und Warmzeiten) gekennzeichnet ist und chronostratigraphisch durch die Serien Pleistozän und Holozän untergliedert wird. Der Begriff wurde formal durch DESNOYERS (1829) eingeführt. Die Grundprinzipien für die Gliederung des Quartärs sind dieselben, die auch für andere chronostratigraphische Einheiten des Phanerozoikum gelten (SALVADOR 1994). Allerdings ist für die Gliederung des Quartärs – im Gegensatz zu anderen Systemen – der Klimawechsel, der in den Sedimentfolgen dokumentiert ist, von entscheidender Bedeutung. Die Klassifikation auf der Grundlage von klimatostratigraphischen Einheiten wie „Glaziale“ und „Interglaziale“ bzw. Warm- und Kaltzeiten besitzt eine lange Tradition und ist in verschiedenen Ländern bzw. Regionen in chronostratigraphischen Standards verankert (GIBBARD & WEST 2000, GIBBARD & VAN KOLFSCHOTEN 2004, LITT et al. 2005). (…)researc

A 500,000-year-long sediment archive drilled in eastern Anatolia

Sedimentary archives host a wealth of information that can be used to reconstruct paleoclimate as well as the tectonic and volcanic histories of specific regions. Long and continuous archives from the oceans have been collected in thousands of locations by scientific ocean drilling programs over the past 40 years. In contrast, suitable continental archives are rare because terrestrial environments are generally nondepositional and/or subject to erosion. Lake sediments provide ideal drilling targets to overcome this limitation if suitable lakes at key locations have existed continuously for a long time

Lake Kinneret (Israel): New insights into Holocene regional palaeoclimate variability based on high-resolution multi-proxy analysis

The southern Levant is a Mediterranean climate zone of complex variability in which uncertainty remains in regional palaeoclimate reconstruction. In spite of the proven value of diatoms in circum-Mediterranean palaeoenvironmental research, their potential remains largely unexplored in the southern Levant region. In this study, we generate a new, high-resolution multi-proxy record for the last ca. 9000 cal. yr BP, supported by diatom data and key biological, mineralogical and geochemical indicators preserved in a 17.8-m-long sediment sequence recovered from Lake Kinneret (the Sea of Galilee), Israel. During the Holocene, well-correlated shifts in the diatom, minero-geochemical and palynological data indicate marked lake-level variation over time as well as changes in the trophic state of Lake Kinneret. Our results are particularly important in improving the reconstruction of Holocene lake-level variation, and thus past moisture availability. Diatom-inferred lake-level oscillations correlate well with the output from climatic models from the Levantine region and clarify previous uncertainty concerning regional variation in moisture availability. The Early Holocene (from ca. 9000 to 7400 cal. yr BP) was characterized by lake-level shifts due to fluctuating dry-wet climate conditions. During the mid-Holocene (from 7400 to 2200 cal. yr BP), a stable, deep lake-level phase persisted due to high humidity. The lake level of modern Lake Kinneret not only fluctuates seasonally with available moisture, but has also been influenced for ca. 2000 years by the impacts of water abstraction for human consumption and agriculture. Over the last 9000 cal. yr BP, the trophic state of Lake Kinneret has changed from an oligotrophic to a meso- to eutrophic environment, mainly triggered by increased human impact from around 2200 cal. yr BP onwards. The lake’s ecosystem status was not strongly affected by the documented major changes in human occupation patterns during the mid-Holocene, when a relatively stable environment persisted

Understanding how Characteristics of the Nest Site Affect Nest Success of Wild Turkeys

Wild turkeys (Meleagris gallapavo) are a highly-desirable game species throughout the United States, but harvest records in the northern Black Hills, South Dakota suggest that this population is declining.  We wondered whether vegetation characteristics at the nest site would affect nest fate (success/failure).  We monitored 40 nests during summer 2016 to determine nest fate and 27 were successful (?1 egg hatched).  At the actual or expected hatch date, we quantified characteristics of the understory vegetation at the nest bowl, namely total cover, shrub cover, woody debris, and the degree of visual obstruction.  We compared these characteristics between successful and unsuccessful nests. Successful nests had slightly less woody debris and total cover than unsuccessful nests.  We did not detect differences in shrub cover or the degree of visual obstruction.  Our results suggest that there may be some optimal amount of total cover and woody debris at the nest bowl that contributes to a higher chance of nest success.  We recommend additional research that focuses on how vegetation characteristics found at nest sites compares to what is available.  This information in conjunction with our findings could provide guidance for managers regarding vegetation characteristics that may be optimal for nest success.  Although these data may help manage turkey populations, nesting represents only one part of the life cycle of a wild turkey.  We recommend that managers strive for a mosaic of vegetation characteristics to accommodate the needs of turkey populations throughout their life history

Genetic and Neuroanatomical Support for Functional Brain Network Dynamics in Epilepsy

Focal epilepsy is a devastating neurological disorder that affects an overwhelming number of patients worldwide, many of whom prove resistant to medication. The efficacy of current innovative technologies for the treatment of these patients has been stalled by the lack of accurate and effective methods to fuse multimodal neuroimaging data to map anatomical targets driving seizure dynamics. Here we propose a parsimonious model that explains how large-scale anatomical networks and shared genetic constraints shape inter-regional communication in focal epilepsy. In extensive ECoG recordings acquired from a group of patients with medically refractory focal-onset epilepsy, we find that ictal and preictal functional brain network dynamics can be accurately predicted from features of brain anatomy and geometry, patterns of white matter connectivity, and constraints complicit in patterns of gene coexpression, all of which are conserved across healthy adult populations. Moreover, we uncover evidence that markers of non-conserved architecture, potentially driven by idiosyncratic pathology of single subjects, are most prevalent in high frequency ictal dynamics and low frequency preictal dynamics. Finally, we find that ictal dynamics are better predicted by white matter features and more poorly predicted by geometry and genetic constraints than preictal dynamics, suggesting that the functional brain network dynamics manifest in seizures rely on - and may directly propagate along - underlying white matter structure that is largely conserved across humans. Broadly, our work offers insights into the generic architectural principles of the human brain that impact seizure dynamics, and could be extended to further our understanding, models, and predictions of subject-level pathology and response to intervention

Commercial Modular Aero-Propulsion System Simulation 40k

The Commercial Modular Aero-Propulsion System Simulation 40k (CMAPSS40k) software package is a nonlinear dynamic simulation of a 40,000-pound (approximately equals 178-kN) thrust class commercial turbofan engine, written in the MATLAB/Simulink environment. The model has been tuned to capture the behavior of flight test data, and is capable of running at any point in the flight envelope [up to 40,000 ft (approximately equals 12,200 m) and Mach 0.8]. In addition to the open-loop engine, the simulation includes a controller whose architecture is representative of that found in industry. C-MAPSS40k fills the need for an easy-to-use, realistic, transient simulation of a medium-size commercial turbofan engine with a representative controller. It is a detailed component level model (CLM) written in the industry-standard graphical MATLAB/Simulink environment to allow for easy modification and portability. At the time of this reporting, no other such model exists in the public domain

Zur Entwicklung der jungquartären Tieflandstäler im Saale-Elbe-Raum unter besonderer Berücksichtigung von 14C-Daten

Erstmalig wurden für den Saale-Elbe-Raum — als geologisch gut erschlossenes Untersuchungsgebiet Mitteleuropas — systematisch gesammelte Proben durch Radiokarbon datiert. Somit ist es möglich, das weichseiszeitliche Alter der intakten und gekappten Niederterrasse zu bestätigen sowie die stark differenzierte holozäne Flußdynamik chronostratigraphisch zu erfassen. Die in der nacheiszeitlichen Flußgeschichte innerhalb eines komplexen Wirkungsgefüges ablaufenden Sedimentationsprozesse wurden in bestimmten Einzugsgebieten durch mittelbare anthropogene Eingriffe bereits seit neolithischer Zeit stark beeinflußt. Dies zeigt sich vor allem im Beginn und Verlauf der Auelehmakkumulation. Durch die radiometrische Datierung subfossiler Hölzer aus holozänen Flußschottern konnte ebenfalls für den mitteldeutschen Raum die Verdrängung der Kiefer durch die Eiche aus den Flußtälern bereits für das Boreal (ältestes 14C-Datum 8790 ± 140 BP) festgestellt werden. Dies stimmt gut mit Befunden aus anderen Flußgebieten vor allem des südlichen Mitteleuropas überein.researc