Search results for "Silt"
showing 10 items of 98 documents
Alternative chronologies for Late Quaternary (Last Interglacial–Holocene) deep sea sediments via optical dating of silt-sized quartz
2003
Abstract We summarize the results of a test on the potential of optical dating for the age assessment of Late Quaternary deep-sea sediments. Our approach combines a single aliquot regeneration (SAR) protocol for equivalent dose ( D e ) estimation on fine silt-sized quartz with a time-dependent evaluation of supported and unsupported long-lived radioisotopes within the deposited sediment matrix. For this purpose nine samples from two independently dated deep-sea cores from the Indian Ocean were obtained. The SAR analysis resulted in mean D e estimates with precisions ranging from 0.9% to 3.7%. Combination of these data with measured radioisotope concentrations resulted in stratigraphically s…
Ceramic production at Selinunte (Sicily) during the 4th and 3rd century BCE: New archaeometric data through the analysis of kiln wastes
2018
Abstract A set of 37 overfired ceramic samples was collected from the dump of two kilns sited in the productive area FF1 in the acropolis of Selinunte (south western Sicily), being specifically active in the period 409–250 BCE. The ceramic samples were analysed by thin-section petrography and chemical analysis, with the aim to establish a valuable ‘reference group’ representative of the ceramic produced at Selinunte during the Punic phase. The petrographic and chemical analyses allowed to state that the ceramic manufactures from the kilns operating in the FF1 insula are characterized by rather homogeneous textural/compositional features. The daily-use common ware here produced is characteri…
Geoarchaeological study of the Phoenician cemetery of Tyre-Al Bass (Lebanon) and geomorphological evolution of a tombolo
2008
The geoarchaeological record of the Phoenician necropolis of Al Bass (Lebanon) provides information concerning the geomorphological evolution of a late Holocene tombolo. Physical and chemical analysis of sediments indicates that the cemetery (9th century B.C.) was located near a littoral lagoon, between the dunes of a cuspate spit pointing toward the island of Tyre. From the sea apex of this spit, the moles mentioned in historical chronicles were constructed. Once mainland and island were connected, at the northern coast (where the port of Sidon was located), a sediment trap was formed, which quickly filled with silt. Afterwards, an extensive field of sand dunes buried all the archaeologica…
Zvaigžņotā Debess: 2009, Rudens (205)
2009
Contents: I.Daube. Jānis Ikaunieks ; A.Balklavs. Mountains on the Venus ; TASS and “Pravda” materials. Soviet Automatic Stations “Venera-5” and “Venera-6” Reach Venus ; A.Alksnis. Gathering of Astronomers at the University ; A.Alksnis, M.Ābele, I.Eglītis, B.Rjabovs, K.Salmiņš, I.Pundure. Directions of Scientific Research of the UL Institute of Astronomy Assessed ; D.Docenko. Meteorite Fallen in Sudan Recovered ; A.Alksnis. How Asteroids Will Disturb Observation with Extremely Large Telescopes ; M.Gills. Daily in Network with Astronomy ; I.Pundure. Arturs Balklavs and Astronomy of Latvia (continued) ; M.Sudārs. IXV – Step towards Reusable Space Vehicles ; V.Kalniņš. Hyperdrive and Heim’s Qua…
Artificial Reefs in North-West Sicily: Comparisons and Conclusions
2000
The most notable features of the biotic colonization and fishing yield of artificial reefs are a straightforward response to local environmental conditions. When applying this assumption to the artificial reefs of north-west Sicily, the features that distinguish the reefs from each other are largely consistent with the major hydrographic characteristics of the Gulf of Castellammare, the Bay of Carini and the Gulf of Palermo. The differences in environmental conditions in the three biotopes have made it possible to compare the colonization of artificial reefs in unpolluted oligotrophic water (Bay of Carini), eutrophic water (Gulf of Palermo) and water with heavy siltation rates (Alcamo Marin…
Antiguos puertos e islas en el litoral andaluz: cartografía, toponimia e historia
2003
Se trata de recordar y agradecer las enseñanzas del Dr. Rosselló y aplicarlas a las costas andaluzas, de cuyas variadas formas llaman la atención los procesos de aterramiento de la parte atlántica, donde hay lugares cuya situación actual no responde a su topónimo (Isla Cristina, San Juan del Puerto...). A estudios anteriores, añadimos noticias históricas y trazados de mapas, que señalan una rápida evolución, referido principalmente a tres ámbitos. La desembocadura del Guadiana, que pasa en época histórica de barras arenosas e islas a zonas cultivadas y urbanizaciones de playas; el antiguo estuario del río Piedras, con puertos aún en el XIX, que sustenta hoy marismas, naranjales y cultivos d…
Prediction of soil texture distributions using VNIR-SWIR reflectance spectroscopy
2013
Abstract Reflectance spectroscopy provides an alternate method to non-destructively characterize key soil properties. Different approaches, including chemometrics techniques or specific absorption features, have been proposed to estimate soil properties from visible and near-infrared (VNIR, 400-1200 nm) and shortwave infrared (SWIR, 1200-2500 nm) reflectance domains. The main goal of this study was to test the performance of two distinct methods for soil texture estimation by VNIR-SWIR reflectance measurements: i) the Continuum Removal (CR) technique that was used to correlate specific spectral absorption features with clay, silt and sand content, and ii) the Partial Least-Squares Regressio…
Development and analysis of the Soil Water Infiltration Global database
2018
27 Pags.- 11 Tabls.- 8 Figs. © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License.
Fluorine adsorption by volcanic soils at Mt. Etna, Italy
2012
Abstract Fluorine adsorption experiments were performed on 28 samples of the first 5 cm of topsoil collected on the flanks of Mt. Etna. The soil samples were equilibrated with F-rich rainwater (3.25 mg/L) at a soil/water weight ratio of 1/25. Aliquots of the supernatant were collected after 1, 7, 72, 720 and 5640 h and analysed for F content. The soil samples could be subdivided into three groups based on their F-adsorption behaviours after 1 h and at the end of the experiment: (1) negative adsorption (F released from the soil to the solution) after 1 h and negative or moderately positive adsorption at the end, (2) from negative after 1 h to strongly positive adsorption at the end, and (3) …
RADIUS - rapid particle analysis of digital images by ultra-high-resolution scanning of thin sections
2005
RADIUS is a newly developed particle-size measurement technique, based on evaluation of digital images of thin sections. Analyses are performed with sub-millimetre sample resolution and are thus designed to work on a single lamina of laminated sediments. The method covers grain sizes from medium silt to coarse sand. The application contains pattern-recognition modules that allow the detection of typical particle distributions of loess, organic detritus, turbidites and tephra layers. Cutting and hiding effects of particles on thin sections are corrected by empirical correction matrices. The calculated analysis results are compared with manually counted and measured samples to calibrate the a…