Search results for "MORPHOLOGY"

On the formation of laminated sediments on the continental margin off Pakistan: the effects of sediment provenance and sediment redistribution

2001

Abstract The sedimentary processes and sediment sources contributing to the formation of laminated sediments along the upper slope off Pakistan are unravelled using inorganic bulk sediment geochemistry of 43 surface cores from the Pakistani continental margin and additional geochemical and Pb and Nd-isotope data for different types of layers. An important process everywhere along the margin is redeposition of fluvial-derived detritus from the shelf onto the slope. This process is of considerably higher intensity along the Makran margin than on the Indus margin. Trace element enrichment related to early diagenesis or surface productivity, which is commonly detectable in bulk sediment composi…

STOP 15: Morphology and internal structure of a ribbed moraine and drumlin remnant in the environs of Baldone, Central Latvian Lowland

2014

On the growth of maars and diatremes and its relevance to the formation of tuff rings

1986

Small and large maars exist associated with small and large diatremes, respectively, their subsurface feeder structures. The problem of size and growth of maar-diatreme volcanoes is discussed from a phreatomagmatic point of view from field data, some geophysical data, and short-lived historic maar eruptions. A hydrostatic pressure barrier of usually about 20–30 bars is assumed to control the maximum depth level of explosive magma/groundwater interactions. Similar to the situation in submarine and subglacial volcanism, initial maar-forming water vapour explosions are therefore assumed to occur at shallow depth and to produce a small maar with a shallow diatreme. Because of limited availabili…

Allium aetnense (Amaryllidaceae), a new species from Sicily.

2013

A new species from Mt Etna (Sicily), Allium aetenense of A. sect. Codonoprasum, is described and illustrated. It is a diploid species (2n = 16) that grows on basaltic rocks in the mountain belt and shows close relationships with A. tenuiflorum of the Italian peninsula. Its morphology, karyology, leaf anatomy, seed coat microsculpturing, ecology and taxonomic position are examined.

PENENTUAN KEDALAMAN SUMUR BOR BERDASARKAN DATA GEOLISTRIK RESISTIVITAS DI BEBERAPA KAMPUNG DI KABUPATEN FAK-FAK

2018

Geoelectrical R esistivity method is a geophysical method that can be used to determine subsurface geology based on rock resistivity image. Resistivity survey has been done in some villages, in Fak Fak Regency, West Papua Province. The measurement method that used is sounding, whereas electrode configuration used is Dipole-dipole configuration with a stretch of 100 -150 m. The data obtained are then processed by Progress Res2Dinv. The results of this survey obtained show that in the resistivity sounding measurement point found any good groundwater aquifers, a s the water source of drilled well . Water layer with the thickness between 1-3 m at the surface (alluvial) is a rain water infiltrat…

The Santa Ninfa Cave (Belice Valley): hydrogeochemical features and relationships with neotectonics

2020

The Santa Ninfa Cave (SNC) develops in an outcrop of Messinian gypsum, located in the heart of the zone struck by the 1968 seismic sequence of the Belice valley. It is composed of different levels of sub-horizontal galleries, the lowest of which is characterized by perennial flowing water, running along the water table. From the hydrogeological point of view, it configures as an open circuit, both inflowing and outflowing from/to neighboring aquifers. The geochemical facies of groundwater collected in the SNC is compatible with a meteoric recharge chemically interacting with evaporitic deposits. The most relevant geochemical feature is the mixing between a small tributary of sulfur water wi…

Glacier drainage and sandur formation at Kötlujökull, South Iceland

1985

Abstract Over a number of years research on a stretch of the southeastern glacier margin of Kotlujokull in South Iceland, 8 km in length, has focused on correlating the manner of glacier drainage with the genesis of sandar, exemplified by the recent evolution of the glacier foreland. The research has yielded the following results. During an initial period, beginning prior to 1945 and ending between 1966 and 1975, a belt of moraines about 1 km wide was destroyed in stages, except for a few remnants, by 11 outbreaks of subglacial meltwater at different times and locations along the glacier front. These outbursts were associated with the genesis of “ordinary”; sandar, which are referred to her…

Integrated geophysical survey for 3D modelling of a coastal aquifer polluted by seawater

2013

Geophysical surveys are carried out in the coastal area of Petrosino (south-western Sicily) to study the time evolution of seawater contamination of the coastal aquifer, probably increased due to human impact. The overexploitation of the aquifer, due to an intensive agricultural use has affected significantly the natural hydro-geochemical state of the basin. The study is based on a processing and integrated analysis of hydrogeological, geochemical and geophysical data. In particular in the last two years seasonal time-lapse electrical resistivity tomographies (ERT), new TDEM soundings and Multi-Analysis Surface Wave soundings (MASW) have been carried out. The interpretation of the total set…

Using LIDAR topography data for determination of morphology and terrace levels of the River Ogre Valley in Middle Latvia Lowland [abstract].

2016

Antarctic erosion history reconstructed by Terre Adélie moraine geochronology

2020

AbstractWe report apatite fission-track and 10Be terrestrial cosmogenic nuclide (TCN) dating of 14 moraine boulders originating from inland Terre Adélie, East Antarctica. These data show cooling of the Proterozoic Terre Adélie craton at < ~120°C between 350 and 300 Ma, suggesting > 4 km temperate glacial erosion during the Late Palaeozoic Ice Age, followed by nearly null Mesozoic erosion and low glacial erosion (< 2 km) in the Cenozoic. Based on glacial flux maps, the origin of the boulders may be located ~400 km upstream. Preliminary TCN (10Be) datings of moraine boulders cluster within the last 30 ka. Cosmogenic ages from the Lacroix Nunatak suggest a main deglaciation after the …