A Natural GMS Laboratory (Granulometry-Morphometry-Situmetry): Geomorphological-Sedimentological-Mineralogical Terrain Analysis Linked to Coarse-Grained Siliciclastic Sediments at the Basement-Foreland Boundary (SE Germany)

Abstract

The “natural GMS laboratory” (granulometry-morphometry-situmetry) is located within the Variscan Basement in SE Germany (Fichtelgebirge Mts.), which is uplifted relative to its Permo-Mesozoic foreland along a deep-seated lineamentary fault zone. This transitional study area is crossed by straight to low drainage systems in the basement, turning meandering channel systems into high sinuosity when entering the foreland. Due to its good geological coverage, the entire region is subjected to an advanced-level terrain analysis and completed with a sedimentological study focusing on the GMS tool. Unlike many applications in the past, the three components of the GMS tool that are of almost equal value ought to be used in combination and not as stand-alone procedures so as to be integrated into other near-surface geoscientific methods, e.g., sediment petrography. The strong points of granulometry of coarse-grained/gravel-sized sediments are its extension into the smaller sand and clay grain size intervals using the sorting, mean and/or median values for an environmental analysis. Morphometry can be linked to the compositional geosciences, e.g., mineralogy and geochemistry. The grain shape is intimately connected with the lithology, providing options from triaxial measuring of the lithoclast to the digital image analysis. It is a favorable tool to supplement the provenance of lithoclasts. Situmetry is the key element of hydrodynamic research and directly builds upon its sister methods. Its applications and numerical approaches are useful for the identification and quantification of physical land-forming processes. It is the fan sharpness and the orientation of lithoclasts relative to the direction of the talweg and in relation cross-sectional valley features that integrate the GMS tool into geological and geomorphological mapping, both of which result in a digital terrain model. Horizontal rose diagrams are useful for the upper reaches of drainage systems, be they of alluvial or non-alluvial types, and vertical ones for alluvial channels in the distal and proximal foreland where stacked patterns of depositional terraces are of widespread occurrence. In general, the GMS tool can be applied to sedimentological, geomorphological, petrographic and tectonic objects in basements and foreland basins; in applied geosciences, it is suitable for the identification of mineral resources and of areas vulnerable to geohazards, and in genetic geosciences for the discrimination of supergene chemical and physical depositional and land-forming processes.

Fluvial Sedimentology of the River Ethiope Sediments, Niger Delta, Southern Nigeria

“…The Ethiope River in the Niger Delta Basin is not an exception; a significant source of water, mineral resources (sands and pebbles) for construction purposes, transportation of timbers, and hospitality/recreational facilities (resorts located along the river banks) to the various communities whose founding is closely related to the existence of this river. Geologically, rivers represent a unique sedimentary environment (continental) marked by processes of erosion, transportation, and deposition of sediments (depending on the flow velocity and the nature of deposits) (Dill et al, 2022). The flow rate of rivers is often heterogeneous, and their bed load is varied, containing different grain sizes ranging from gravel, sand, and silt to clay (e.g.…”

“…Fluvial facies in the rock record are numerous and have played host to hydrocarbons and water as they have served as significant hydrocarbon reservoirs and aquifers, respectively. Significantly, modern river systems are well-studied to better our understanding of how ancient fluvial facies operated (Sames, 1966;Friedman, 1961;1967;Moiola and Weiser, 1968;Visher, 1969;Zhang et al, 2020;Adiotomre et al, 2021;Dill et al, 2022).…”

“…Modern fluvial sedimentology has been a subject of interest for the past five decades (e.g. Calgary, 1977;Miall, 1987;Adiotomre et al, 2021;Dill et al, 2022).…”