Sedimentene

Sedimentene is a term used in sedimentary geology to describe a class of sedimentary composites formed when mineral grains and organic matter co-deposit and interact during sedimentation and early diagenesis. It refers to heterogeneous, integrated matrices found in some fine-grained sediments, rather than a distinct mineral species. Sedimentene-rich sediments are typically found in lacustrine and marine settings where slow deposition and reduced conditions promote intimate mixing of components.

Composition and structure commonly include silicate minerals such as quartz and clays, with minor feldspars, and substantial organic material that can resemble kerogen. Iron oxides may be present in some samples. Microtextures often show lamination or nodular features and a binding network of organic polymers that links grains, enhancing cohesion in the matrix.

Formation and diagenesis involve deposition in quiet water, where microbial activity produces extracellular polymeric substances that bind particles. Early cementation by carbonates or iron oxides can occur, and subsequent compaction modifies pore spaces and fabric. These processes can create a cohesive, layered material with variable porosity and permeability.

Occurrence and significance: reports of sedimentene-like fabrics span various sedimentary environments, including lake basins, continental margins, and deltaic settings. They can influence carbon storage, sorption of contaminants, and the interpretation of paleoenvironmental conditions through their organic and mineral signatures. Understanding sedimentene helps in reconstructing sedimentary dynamics and assessing reservoir quality in fine-grained rocks.

Analytical approaches include optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, and geochemical/isotopic analyses to characterize mineralogy and organic matter.