#geomorphology

• Geological ablation — A conceptual form or terminological variant of 'ablație', used in classical geomorphology to describe the phenomenon of removal, washing away, or baring of rocks under the action of external agents (wind, flowing waters, waves). In soil dynamics, the term emphasizes the initial transport phase of fine detrital materials before they are deposited in sedimentary basins.
• Adularia — A structural variety of orthoclase (potassium feldspar) presenting as transparent to translucent, colorless or whitish crystals, characterized by a specific silvery or opalescent schiller known as adularism. Named after the Adula Alps in Switzerland, where it was historically found within hydrothermal veins of metamorphic rocks. Due to its unique optical properties, fine specimens are cut as moonstones for gemology, while bulk materials are applied in high-grade ceramics and glass manufacturing.
• Alluvial deposit — An accumulation of alluvial materials, silt, gravel, branches, or vegetative debris brought by the flooded waters of a river or stream and deposited at points where the current velocity decreases. This natural phenomenon structurally modifies the minor bed and can cause natural damming or course deviations.
• Silting up — The act of clogging and its result; a natural or accidental process through which a riverbed or drainage channel becomes blocked due to the massive accumulation of alluvium, silt, gravel, and woody debris transported by floods. This phenomenon causes a reduction in the flow cross-section and the silting up of the watercourse.
• Silting up — The act of silting up and its result; a lexical variant for the natural process of clogging and obstructing a riverbed or channel through the accumulation of alluvium, sediments, and plant debris. It represents the dynamic nominalization of the verb 'a agesti'.
• Alluvial deposits — A rare plural form or local collective variant for repeated accumulations of alluvium, sediments, silt, and woody debris deposited along a riverbed following several successive floods. It defines the unstable microrelief made of gravel bars and alluvial ridges.
• Silting up — A rare lexical or derivative variant for the act of silting up or clogging; the dynamic process of accumulation and natural damming of a riverbed through alluvium, fine sediments, silt, and plant debris transported by floods. This phenomenon causes a structural modification of the cross-sectional profile of the watercourse.
• Alluvial deposit — A phonetic or regional variant for the term 'agest'; an accumulation of alluvial materials, silt, gravel, and woody debris brought by floods and deposited in a stream bed. It designates a natural blockage or a sedimentary mound formed in areas where the current velocity drops suddenly.
• Troughed — Having a hollowed-out, deepened, or concave shape, similar to the structure of a trough or a riverbed; provided with a visible channel. In geography and geomorphology, the term describes a valley, a canal, or a relief segment shaped by continuous fluvial erosion. In an archaic sense, it can also refer to a log or wooden object already hollowed out by a craftsman.
• Riverbed — The part of a valley through which a river flows, permanently or temporarily; a large wooden or metal trough used in households for washing clothes, kneading dough, or feeding animals. It represents an elongated structural depression, natural or artificial, bordered by side walls.
• Small trough — Diminutive for albie; a small-sized trough or wooden bowl used in households; a small natural depression or narrow riverbed of a brook or mountain river.
• Almas-Agrij — The name of a complex landform unit in northwestern Transylvania (Romania), representing the Almaș-Agrij Depression or the depressional sector bounded by the valleys of the Almaș and Agrij rivers in Sălaj County. This contact zone between the Apuseni Mountains and the Someșan Plateau is recognized for its hilly landscape, dense hydrographic network, and Roman and medieval historical remains.
• Almașu Mare — The name of a commune and its homonymous residential village located in Alba County, Transylvania, Romania, situated in the Metaliferi Mountains. The region is famous since antiquity (the Daco-Roman period) for its rich gold and precious metal mining operations, while also hosting spectacular natural monuments such as the Cibul or Glod Gorges and a valuable local ethnographic museum.
• Allogenetic — Pertaining to or relating to allogenesis; generated, developed, or supplied from external sources foreign to the local environment. In speology and karstology, it describes a karst system, cave, or watercourse fed by precipitation or rivers that originate on neighboring non-karstifiable rocks (such as granites or schists) and subsequently enter the limestone massif.
• Allogenesis — A process of formation, development, or evolution determined by external factors or forces foreign to the internal structure of the analyzed system. In geology, it refers to the accumulation within a basin of sediments and minerals formed outside of it and mechanically transported; in biology, it defines a secondary evolutionary direction marked by specific adaptations to new local environments, without an increase in general structural complexity.
• Altiplanation — A complex geomorphological process of leveling and flattening landforms in high mountainous regions, occurring under the combined action of repeated freezing and thawing (frost wedging, solifluction, and nivation); leads to the formation of stepped terraces and flat platforms called altiplanation surfaces.
• Sliding — The act of slipping, sliding, or gliding and its result; a continuous and smooth movement over a glossy or wet surface. In geomorphology, it designates the natural or accidental displacement of soil or rock masses down an inclined slope, caused by water infiltration or gravity (landslide).
• Landslides — Plural form of the feminine noun 'alunecare'; designates multiple geomorphological phenomena involving the displacement of soil or rock masses down inclined slopes, or repeated mechanical sliding actions.
• Alluvium — A mass of silt, sand, gravel, and organic debris transported by running waters and deposited in riverbeds, floodplains, deltas, or at river mouths, at points where current velocity decreases. In a legal and structural sense, it represents the gradual and imperceptible increase of a riparian land through the natural input of sediments brought by a river.
• Anaclinal — Flowing or oriented in a direction opposite to the dip of structural geological strata; said of a valley or a watercourse that traverses a relief by cutting through rocky layers contrary to their natural deposition slope. It represents a fundamental concept in hydrographic network analysis, often indicating very old watercourses that predate the tectonic movements that tilted those strata.