1997年6月1日 · Two types of cemented beach deposits occur on reef islands off the coast of Belize. These are (1) intertidal beachrock that is dominantly cemented by marine aragonite and high-magnesium-calcite cements, and (2) supratidal cayrock that is cemented mainly by vadose low-magnesium-calcite cements.

2022年9月1日 · X-ray diffraction analysis of such heavy placers indicate the presence of predominant ilmenite, almandine garnet, zircon, monazite and ferrihydride. The sediments from other areas are rich in lighter minerals of quartz, albite and magnesium-calcite representing the average beach sediment mineralogy of SE coast.

2000年5月1日 · High Mg calcite (often micritic) and aragonite are the commonest cement types, although low Mg calcite cements are common from temperate zone beachrocks. Degassing of CO 2 from groundwater, mixing of meteoric and marine waters, biological influence and evaporation of seawater have all been proposed as possible causes of precipitation of ...

Two types of cemented beach deposits occur on reef islands off the coast of Belize. These are (1) intertidal beachrock that is dominantly cemented by marine aragonite and high-magnesium-calcite cements, and (2) supratidal cayrock that is cemented …

1998年5月29日 · Geometrically, calcite cementation in shallow marine sandstones typically occurs as continuously cemented layers, as layers of stratabound concretions, and as scattered concretions. All these forms can be explained by local diffusional redistribution of biogenic carbonate originally present within the sandstones.

Two types of cemented beach deposits occur on reef islands off the coast of Belize. These are (1) intertidal beachrock that is dominantly cemented by marine aragonite and high-magnesium-calcite cements, and (2) supratidal cayrock that is cemented …

2009年4月1日 · Most deposits of calcite-cemented sands elsewhere, worldwide, are shallow marine shelf or near-shore marine-influenced deltaic sediments permitting significant accumulations of shell debris...

2021年3月30日 · Calcite and dolomite are major sources for the high concentrations of Ca and Mg, especially in the northern sections of the study area, while augite, clinoenstatite, ankerite, clinopyroxene, cordierite, magnetite are likely sources of Si, Mg and Fe.

Clastic sedimentary features of beachrocks and unconsolidated deposits of parent beaches were investigated along the northern Aegean coastline (Greece) to assess their suitability in palaeo-environmental reconstruction.

2018年9月10日 · The two common forms of precipitated calcium carbonate minerals found in the ocean are calcite (e.g., clams) and aragonite (e.g., snails). They share the same chemical formula but differ in structure with calcite being more stable than aragonite.