Search results for "Structural basin"
showing 10 items of 292 documents
Assessing sediment connectivity in dendritic and parallel calanchi systems
2019
Abstract Calanchi, a type of Italian badlands created by a combination of water erosion processes and environmental constraints controlling their development, is a striking example of long-term landscape evolution. Sediment connectivity can be defined as the degree to which a system facilitates the fluxes of sediments through itself. The goal of this research is testing the use of simple morphometric variables for assessing sediment connectivity of calanchi landforms distinguishing between dendritic and parallel systems. For detecting the morphological characteristics controlling the sediment connectivity of calanchi basins, literature data (146 calanchi basins) and measurements carried out…
Submarine canyon morphologies in the Gulf of Palermo (Southern Tyrrhenian Sea) and possible implications for geo-hazard
2011
12 pages, 12 figures, 1 table.
Potential Cyclic Steps in a Gully System of the Gulf of Palermo (Southern Tyrrhenian Sea)
2016
Multibeam bathymetric data revealed the occurrence of atrain of bedforms along a gully system in the Gulf of Palermo, Southern Tyrrhenian Sea. The observed gullies, located in the westernmost sector of the Gulf of Palermo, incise the outer shelf at a depth of 120 m and converge at the Zafferano Canyon, connecting to the Palermo Basin at a the depth of 1300 m. Bedforms develop along these gullies and along the thalweg of the canyon, displaying an average wavelength of 200 m, with maximum values of 340 m. Their gully floor location combined with their wave length, upslope asymmetry and crescent shape point to a possible cyclic steporigin of these bedforms. Preliminary numerical modeling sugge…
Catchment size and contribution of the largest daily events to suspended sediment load on a continental scale
2013
Abstract The classic approach defines an extreme event as a rare event identified by magnitude–frequency analysis and quantified by its deviation from a central value. They are key to understand geomorphological dynamics, since they are responsible for a considerable amount of work and “time compression”. Time compression means that most of the geomorphic work (particularly sediment transport) is produced in very short temporal intervals (i.e. in few events). Moreover, it is well known from magnitude–frequency analyses that events not necessarily extreme by magnitude could be responsible for a large amount of geomorphic work. To analyse the time compression of geomorphological processes, a …
A shallow water model with eddy viscosity for basins with varying bottom topography
2001
The motion of an incompressible fluid confined to a shallow basin with a varying bottom topography is considered. We introduce appropriate scalings into a three-dimensional anisotropic eddy viscosity model to derive a two-dimensional shallow water model. The global regularity of the resulting model is proved. The anisotropic form of the stress tensor in our three-dimensional eddy viscosity model plays a critical role in ensuring that the resulting shallow water model dissipates energy.
THE TOPOLOGY OF BASIN BOUNDARIES IN A CLASS OF THREE-DIMENSIONAL DYNAMICAL SYSTEMS
1996
We will develop new methods to determine the topology of the basin boundary in a class of three-dimensional dynamical systems. One approach is to approximate the basin boundary by backward integration. Unfortunately, there are dynamical systems where it is hard to approximate the basin boundary by a numerical backward integration algorithm. We will introduce topological methods which will provide new information about the structure of the basin boundary. The topological invariants which we will use can be numerically computed.
Population response during an Oceanic Anoxic Event: The case of Posidonotis (Bivalvia) from the Lower Jurassic of the Neuquén Basin, Argentina
2019
Benthonic marine species show a wide range of biological reactions to seawater chemical changes through time, from subtle adjustments to extinction. The Early Toarcian Oceanic Anoxic Event (T-OAE) was recently recognized in the Neuquén Basin, Argentina, confirming its global scope. The event was identified chemostratigraphically on the basis of a relative increase in marine organic carbon and a characteristic negative carbon-isotope excursion (δ13Corg) in bulk rock and fossil wood in the upper Pliensbachian–lower Toarcian interval in the Arroyo Lapa section (Neuquén). Simultaneously with collection of lithological samples, a high-resolution biostratigraphical survey was carried out, and the…
Rodents and insectivores from the Lower Miocene (Agenian and Ramblian) of the Tudela Formation (Ebro Basin, Spain)
2012
The rodent and insectivore faunas of Agenian and Ramblian age from the Tudela Formation (Ebro Basin, Spain) are described. Four of the localities (CH1, CA1, CC1 and CA2) contain rodent remains of Agenian age (local zone Y), and three (CA3, CA3B and CA4) of Ramblian age (local zones Z and A). Typical Agenian taxa include Armantomys cf. bijmai (CH1), Eucricetodon cf. gerandianus (CA1), Peridyromys turbatus, Simplomys aff. aljaphi and Armantomys daamsi (CA2) and Eucricetodon aff. aquitanicus (CC1). On the other hand, some typical Ramblian taxa are Armantomys cf. parsani (CA3), Ligerimys aff. magnus and Pseudotheridomys sp. (CA4) and Prodryomys cf. brailloni (CA3B). The faunas are characterized…
Past and Current Climate Change
2008
This section describes long-term observed climatic changes in atmospheric parameters. The focus is on surface climate conditions, but changes in atmospheric circulation are discussed as they often are behind climatic variability seen on regional and local scales. For a summary introduction on mean atmospheric states and conditions in the Baltic Sea Basin see Annex 1.2 with sections on the general atmospheric circulation (A.1.2.1), surface air temperature (A.1.2.2), precipitation (A.1.2.3), clouds (A.1.2.4), and global radiation (A.1.2.5).
Diversity of large ornithopod dinosaurs in the upper Hauterivian-lower Barremian (Lower Cretaceous) of Teruel (Spain): a morphometric approach
2020
We report some large ornithopod vertebrae from two upper Hauterivian-lower Barremian (Lower Cretaceous) localities in El Castellar (Maestrazgo Basin, Teruel,Spain).These fossils have been studied systematically as well as morphometrically using a multivariate analysis in order to analyse the diversity of the sample. In fact, principal component analysis has been demonstrated as a useful tool for establishing affinities in isolated iguanodontian vertebrae, at least when size effect is not removed from the analysed dataset. As result of this study, twolarge indeterminate styracosternans are distinguished in the sample: a large one with platycoelus anterior caudal vertebrae related to the gene…