Introduction. The current hypothesis is that Martian sinkholes do not exist. It is proposed that the low pH environment resulting from the high CO2 content of the atmosphere will cause calcium carbonate to be deposited as calcite cemented sandstone rather than limestone [5]. Calcite, as well as gypsum, halite, smectite and illite, has been detected in Martian meteorites providing proof of the p...

Paleocene and  Lower Eocene deposits in SW Iran are known as Pabdeh formation.Pabdeh formation is one of the most important lithostratigraphy unit as source rock has been deposited in Zagros basin over an extremely long period in time. The area under research is the Ghachsaran 55 subsurface Section located  from the Ghachsaran oil field in Dezful embeyment in zagros fold zone. The Lower boundry...

Silica fume has been largely used in concrete in recent decades due to its effect on improvement of strength and durability of concrete. On the other hand, attention has been recently paid to the use of limestone powder as a substitute for part of cement in concrete, basically because of its low price and its positive effect on the durability of concrete. The aim of the current study is the i...

A new species of Adiantum is described from California. This species is endemic to northern California and is currently known only from Shasta County. We describe its discovery after first being collected over a century ago and distinguish it from Adiantumjordanii and Adiantumcapillus-veneris. It is evergreen and is sometimes, but not always, associated with limestone. The range of Adiantumshas...

for obtaining reservoir petrophysical properties, for example porosity, non-destructive methods such as x-ray computed tomography, ct, seems to be precise and accurate. porosity is deducted from the ct image with a single scan via different techniques, such as pore space detection by image segmentation techniques then correlation with porosity. more than one hundred samples with carbonate litho...

Rapid population growth and increasing demand for the modern settlement has led to the increase of environmental pollution. Limestone quarry is one among the activities that affect environment and ecosystem in Pemba Island-Zanzibar. Quarrying activities brought an inevitable destruction to the environments ranging from excavation, soil and land degradation, loose of biodiversity and water pollu...

The activity concentrations of 40K, 232Th, and 238U in the characteristic rocks of the Modane-Aussois region (Western Alps, France) were determined using an HPGe gamma-ray spectrometry system. The activity concentrations of 40K varied from 18 Bqkg-1 (limestone dolomite) to 392 Bqkg-1 (calcschist), while those of 232Th varied from 0.7 Bqkg-1 (limestone dolomite) to 18 Bqkg-1 (calcschist). The ac...

The Neolithic menhir El Gustal is located on a karstificated Coniacian limestone. The original morphology of the monolith and the pit has been preserved, and fragments of limestone filled the hollow. This has made it possible to identify construction phases of the most elementary stone constructive typology. Firstly, the original position of the monolith in the quarry of origin has been determi...

this paper aims at investigating the influence of partial replacement of portland cement with ultrafine fillers compared to limestone powder on the durability and mechanical characteristics of concrete. for this purpose, ultrafine calcium carbonate materials with different specific surface areas of 9.7 and 15.1 m2/g and limestone powder (0.72 m2/g) were used. the results indicate that the ultra...

Francois' langur (Trachypithecus francoisi) is an endangered primate and endemic to the limestone forests of the tropical and subtropical zone of northern Vietnam and South-west China with a population of about 2,000 individuals. Conservation efforts are hampered by limited knowledge of habitat preference in its main distribution area. We surveyed the distribution of Francois' langur and modele...