Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: skały kredowe

Sortuj według:

Ogranicz wyniki do:

Effects of porosity and composition on seismic wave velocities and elastic moduli of lower cretaceous rocks, central Lebanon

Salah M. K., Alqudah M., El-Aal A. K. A, Barnes C.

Acta Geophysica

2018

Vol. 66, no. 5

867--894

We collected 40 rock samples from the Cretaceous strata exposed at central Lebanon in order to study the effects of porosity and rock composition on their seismic wave velocities and elastic moduli. Several sedimentological and mineralogical studies were conducted to evaluate the rock composition, provenance, depositional conditions, and the diagenetic history of the studied rocks. Porosity, bulk and grain densities and seismic wave velocities were measured for 35 drilled core samples at ambient conditions in the laboratory. Velocity measurements were conducted on the dry core samples utilizing the pulse transmission technique. Petrographically, four lithofacies have been identified under the polarizing microscope. From oldest to youngest, these comprise arenitic sandstone, lithic limestone, oolitic limestone, and micritic limestone. Investigations of representative rock samples under the SEM revealed that a number of diagenetic processes have impacted the studied rocks, and thereby affected their petrophysical properties. The XRD analysis, on the other hand, revealed that quartz and calcite are the dominant minerals in the sandstones of the Chouf Formation and the limestones of the Abeih and Mdairej Formations, respectively. The measured porosity, bulk density, and compressional and shear wave velocities of the investigated rocks vary, respectively, between 2.14–10.05%, 2.41–2.67 g/cm3, 3885–6385 m/s and 2246–3607 m/s. The grain density was calculated from the measured porosity and bulk density data and varies narrowly between 2.64 and 2.78 g/cm3. We further calculated the Poisson’s ratio and the moduli of shear, bulk, and Young from the measured bulk density and seismic wave velocities. Calculated values of these parameters vary between 0.18–0.28, 1.23–3.43 × 1010 Pa, 2.03–6.18 × 1010 Pa and 3.06–8.69 × 1010 Pa, respectively. The generalized mixture rule is used to provide a unified description of the physical properties of the studied rocks regarding their component properties, volume fractions, and microstructures. We constructed a number of relationships between the measured petrophysical and elastic properties to evaluate the mutual interdependence of these parameters and assess the effects of porosity and rock type on these important rock characteristics.

Zbigniew Sujkowski – uczony i żołnierz

Miecznik J. B.

Przegląd Geologiczny

2014

Vol. 62, nr 5

234--239

Zbigniew Sujkowski was a co-founder of Polish sedimentary petrography and a pioneer of sedimentology. After studying geology at the University of Warsaw (1921–1925), he worked in 1927–1929 with Prof. Lucien Cayeux at Collège de France in Paris. He specialized in petrographic-sedimentological studies of Cretaceous deposits in Poland, but especially of siliceous rocks. His treatise on diagenesis, published posthumously in 1958, is among the classics of world geological literature. Zbigniew Sujkowski was a Polish patriot. In the period 1914–1920, he participated in the armed struggle for the independence of Poland, and during World War II – in the armed resistance movement against German occupation as the organizer of subversion. At the end of the war, he was in London; his return to Poland was impossible from political reasons. Sujkowski immigrated to Canada and took a job at MacMaster University in Hamilton. He died tragically in an accident.