Diagenesis of Miocene Sandstone in the District Sudunhoti and Poonch, Azad Jammu and Kashmir, Pakistan

Abstract

The petrographic analysis of Miocene sandstone at latitude 33° 45' 00" N to 33° 51' 30" N and Longitude 73° 35' 36" E to 73° 45' 00" E in the Himalayan fold and thrust belt was based on field observations and study of representative samples. At least 30 rock samples dislodged from outcrops for thin section preparations were soaked in blue epoxy resin before thin section grinding, then etched and stained using alizarin-red and potassium ferrocyanide for carbonate identification. The stratigraphic sections in the area were measured by tape-compass-clinometer method. Petrographic and textural data revealed that the quartz, feldspar, rock fragments, accessories, matrix and cement form the bulk composition of the rocks. The Miocene sandstones are lithic arenites and lithic greywackes. Further interpretation revealed the fracturing, flexure grain deformations, dissolutions, stylolitization, clay minerals anthogenesis, calcite and silica cementation during the diagenetic history of rocks.

PETROGRAPHIC, PHYSICAL AND MECHANICAL PROPERTIES OF SANDSTONE OF MIRPUR DISTRICT AREA STATE OF AJ&K, PAKISTAN

“…Apart from calcite, silica also acts as cementing material. The silica content in sandstone increases with decrease in matrix content [11]. Minor amount of chart is precipitated between pore spaces of sandstone.…”

“…The polycrystalline quartz grains are easily deformed by pressure solution than the monocrystalline quartz. The calcite is the dominant type of cement precipitated between pore spaces of lit arenites and greywacke during lithification [11]. Cement is compaction agent greater amout in pore spaces have greater compaction.…”

Macro-Micromechanical Properties of Sandy Pebble Soil of Different Coarse-Grained Content

“…In this test, the sandy pebble soil in Chengdu City, Sichuan Province, China was taken as the research object, for the oversized particles, the weighted average substitution was conducted using the sandy pebble soils with the maximum allowed particle size of 60 mm to 5 mm according to the content, namely equivalent substitution method (Yasin, 2017;Kudus et al, 2017). To obtain the shear strength index of sandy pebble soil of different coarse-grained content, a total of four groups of specimens with P5 (mass percentage of particles with particle size of greater than 5 mm) of 73%, 75%, 76.5% and 80% were adopted in this test, with density of 2.05 g/cm3, moisture content of 1.6%.Each group of specimens was exerted with confining pressures of 100 kPa, 200 kPa, and 300 kPa.…”