Search results for "rock"

The niobium and yttrium abundances in the sedimentary gem deposits of Sri Lanka

1986

Mylonites Derived From Parent Rocks Other Than Granites and Gneisses

2009

Most mylonites shown in this atlas are derived from granites and gneisses. This is not a coincidence; the mineralogy of these rocks favours the formation of mylonites because of the contrasting behaviour of quartz and biotite on the one hand (forming matrix) and feldspar and muscovite on the other hand (forming porphyroclasts). Another group of rocks that readily forms mylonites are impure quartzites in which resistant minerals tend to form fish-like structures, again, by strong contrast in rheological behaviour.

Kämmensyrjävaimennuksen tuottamat musiikilliset prosessit extreme metal -musiikin muodon artikuloijina

2013

Natural radioactivity in the Alte Madonie Mounts (Sicily, Italy)

2009

With the collaboration of geology experts, we have taken 45 samples of selected soils and rocks. All samples were powdered, dried and sealed in “Marinelli” beakers for 20 days before the measurement so as to ensure that radioactive equilibrium between 226Ra and 214Bi has been reached. Mineralogical and chemical features of the samples were determined by XRD and XRF analysis, instead Gamma ray spectrometric analysis was used in order to quantify radioactivity concentrations. The average values of concentrations of 214Bi, 228Ac and 40K are respectively 30, 19 and 258 Bq/kg while the greatest values were 134, 59 and 748 Bq/kg. A linear relationship exists between 214Bi, 228Ac and 40K activitie…

Rockfall hazard assessment of the Monte Gallo Oriented Nature Reserve area (Southern Italy)

2021

Abstract The Monte Gallo area is a carbonate relief that develops a significant nature reserve and highly attracts tourism to the urbanized area of the City of Palermo (Southern Italy). The slopes are affected by several rockfall events, which have also caused death, injuries, material damage, and a strong social and economic impact. Here, a detailed geological and geotechnical study to assess the rockfall hazard relating to two sectors of the mount has been carried out. The hazard assessment at the slope scale was performed based on geological, geomorphological, geomechanical, and seismic analysis. Using both analytical and empirical methods and by means of different software, the reconstr…

Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa.

1994

Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the …

Mesoscopic structure of marble determined by combined USANS and SANS

2006

Marbles, carbonatic (i.e. calcitic–dolomitic) rocks deriving from the metamorphic evolution of previous carbonates, are often rather similar to each other in many respects (i.e. mineralogical, physical–structural and chemical), and thus difficult to identify. In search for a diagnostic method to provenance marbles, we have selected a limited number of Italian white marbles representing a wide array of metamorphic (i.e. thermal) levels. The mesoscale structural arrangement of these samples was derived by means of combined Ultra Small Angle and Small Angle Neutron Scattering experiments. The parameters of the model used to fit the data have been correlated with the metamorphic history of the …

High-accuracy mass spectrometry of fission products with Penning traps

2012

Mass measurements of fission products based on Penning-trap technique are reviewed in this article. More than 300 fission products have been measured with JYFLTRAP, ISOLTRAP, CPT, LEBIT and TITAN Penning traps with a typical precision of δm/m ≈ 10−7 − 10−8. In general, the results agree well with each other. The new data provide a valuable source of information and a challenge for the future development of theoretical mass models as well as for obtaining a deeper insight into microscopic properties of atomic nuclei as measured, for example, via key mass differentials. Shape transitions around N = 60, subshell closure at N = 40 and shell closures at N = 50 and N = 82 have been investigated i…

Bedrock Characterisation of Four Candidate Repository Sites in Finland As Determined by He-Gas Methods

1999

AbstractAt the end of the year 2000, one of four sites will be chosen as the final repository site in Finland. Therefore accurate and comprehensive statistics of the bedrock characteristics such as porosity [% ] and effective diffusion coefficient [m2/s ] of these sites are of importance. Altogether 115 rock samples from the four sites were measured by different He-gas methods to achieve this goal.The results obtained indicate that the average bedrock properties at these sites are quite similar. Variations among individual samples and different rock types within one repository site were larger than variations among the averaged values of the four sites. Some indication of increased microfra…

Heavy ion and proton test site at JYFL-accelerator laboratory

1999

Abstract A radiation effects facility (RADEF) has been installed in the Accelerator Laboratory of the Department of Physics, University of Jyvaskyla (JYFL). The facility includes a special beam line dedicated to irradiation studies of semiconductor components and devices. It consists of a vacuum chamber including component movement apparatus and the necessary diagnostic equipment required for beam quality and intensity analysis. Construction of the station began in the summer of 1996, and in August 1997 the suitability of the station for space applications was evaluated. In this paper we introduce the accelerator laboratory along with the test station and its properties. We also describe th…