In this paper, the needle penetrometer test was utilized to explore the reliability of the Needle Penetration Index (NPI) for estimating the Unconfined Compressive Strength (UCS) of sedimentary rocks including gypsum, marl, siltstone and sandstone collected from the Qom Formation. Following the UCS and NP test, regression analyses were carried out to control the predictive performances of NPI. ...

   The study area is located in the northeast of Iran. Miankuhi Formation is 500m thick and comprises homogeneous shales, brown granular sandstone and siltstone. In this study, 45 samples were taken from Miankuhi shales and sandstones in order to determine their tectonic origin by using a polarizing microscope. Samples were analysed by X-Ray Fluorescence (XRF) method to determine their chemical...

Detailed knowledge of chemical, petrographic and mineralogical compositions as well the effects applying rock powder on soil chemical properties plant production are required for classifying these materials remineralizers (SR), according to Brazilian legislation in force. This study aimed evaluate potential powders siltstone, tephrite olivine melilitite, pure or mixed, improving fertility a Cam...

Sandstones that overlie or that are interbedded with evaporitic or other ductile strata commonly contain numerous localized domains of fractures, each covering an area of a few square miles. Fractures within the Entrada Sandstone at the Salt Valley Anticline are associated with salt mobility within the underlying Paradox Formation. The fracture relationships observed at Salt Valley (along with ...

Multistage constant-amplitude-cyclic (MCAC) loading experiments were conducted on Tibet interbedded skarn to investigate and characterize fatigue mechanical behavior of the tested rock. Rock volumetric deformation, stiffness change, damage evolution analyzed along with macroscopic failure morphology. The experimental results demonstrated that deformation was influenced by interbed structure. pr...

Early Palaeoproterozoic (2.5-2.0 billion years ago) was a critical phase in Earth's history, characterized by multiple severe glaciations and a rise in atmospheric O(2) (the Great Oxidation Event). Although glaciations occurred at the time of O(2) increase, the relationship between climatic and atmospheric transitions remains poorly understood. Here we report high concentrations of the redox-se...