#sediment

• Actinamea — Romanian name adapted from the taxonomic genus Actinamea, representing a category of microscopic or meiofaunal marine organisms within the phylum Cnidaria or related to sea anemones. These possess a simple structural body, often adapted to interstitial life inside sandy sediments, and are characterized by tentacles symmetrically arranged around the oral disc, resembling a star or a ray.
• Aquitanian — The first geochronological stage or subdivision of the early Miocene epoch, situated at the base of the Neogene period, covering a time interval from around twenty million years ago; also, as an adjective, it describes geological elements from this stage or refers to the Aquitaine region in France and its historical inhabitants. This structural term marks a major transitional geological period, defined by global climatic shifts and significant tectonic movements.
• To clog with debris — To gather, accumulate, or heap up alluvium, branches, and debris brought by waters; to cause a blockage on a river course. As a reflexive form, it applies to waters that stop due to a structural obstacle or to materials that pile up at a certain point.
• To silt up — A rare verbal form or conjugation variant describing the process of accumulating alluvium, silt, and vegetative debris in a riverbed; to silt up or become blocked due to deposits brought by floods. As a transitive form, it defines the current's action of transporting and heaping solid materials at a critical point of the watercourse.
• 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.
• Albian — The final stratigraphic stage or age of the Early (Lower) Cretaceous epoch, situated in geological chronology after the Aptian and before the Cenomanian, dated approximately between 113 and 100.5 million years ago. As an adjective, it applies to rocks, sediments, limestone deposits, or fossils characteristic of this geological period, extensively studied in Carpathian paleontology.
• Aleurite — A friable, unconsolidated, or weakly consolidated sediment composed of fine mineral fragments (chiefly quartz, feldspars, and clay minerals) whose dimensions are intermediate between those of sand and clay (ranging from 0.002 to 0.06 millimeters). It represents the main component of dust and loess, transforming through diagenesis and geological compaction into the sedimentary rock known as aleurite or siltstone.
• Aleuritic — Pertaining to aleurite, regarding aleurite, or containing fine detrital elements with sizes intermediate between sand and clay. In structural geology, the term describes the texture or structure of sedimentary rocks where microscopic mineral particles (dust or silt) predominate, giving the rock a mealy feel and specific mechanical properties regarding permeability and cohesion.
• Aleurolite — A consolidated detrital sedimentary rock formed through the cementation and diagenesis of aleurite (fine mineral dust, chiefly quartzous). The dimensions of its component grains are intermediate between those of sandstones and argillites, ranging from 0.002 to 0.06 millimeters. It often exhibits fine stratification and is used in geology to reconstruct ancient fossil or lacustrine sedimentary environments.
• Allochems — Organized structural components of carbonate origin that formed by chemical precipitation or biological activity within a sedimentary basin and underwent local transport before final deposition; they include ooids, bioclasts, intraclasts, and peloids, representing the major constituent elements of many limestone rocks according to Folk's classification.
• Allogenous — Of a different origin, born or formed elsewhere than its current location; an element (mineral, rock fragment, population, or individual) that is foreign to the indigenous environment in which it is integrated. In geology, it defines minerals transported from the outside and deposited in a sedimentary basin, while in sociology and anthropology, it refers to population groups originating from a geographic or cultural region different from the native one.
• 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.
• Allochthonous — Having formed or originated elsewhere than its current location of deposition or existence; an element (rock mass, mineral, plant or animal species) foreign to the local environment in which it is integrated. In geology, it defines thrust sheets or sediments transported from great distances by tectonic or water forces, whereas in ecology it designates a species introduced into a biotope distinct from its native range.
• Alluvial — Coming from alluvium, formed by the gradual deposition of silt, sand, gravel, and organic debris brought by running waters; pertaining to alluvium, specific to floodplains or river deltas. In a pedological and structural sense, it describes a fertile soil type or a sedimentary terrain recently formed in river valleys through dynamic fluvial accumulation processes.
• Alluvium — A secondary, regional, or archaic form of the noun 'aluviune'; a sedimentary mass consisting of silt, sand, gravel, and organic debris transported and deposited by running waters in floodplains, deltas, or at river mouths. In certain old agricultural documents, the term describes new land formed by fluvial accumulation at the edge of a property.
• Silt up — To deposit alluvium, to cover a piece of land or a riverbed with layers of silt, sand, and gravel brought by waters; to undergo a process of silting or sedimentary accumulation. In hydrotechnics, it describes the action by which a river modifies the dynamic relief of an area by dropping transported materials at points where current velocity decreases.
• Alluvial — Coming from alluvium, composed or formed by the gradual deposition of silt, sand, gravel, and organic debris transported by running waters; characteristic of alluvium. In a geomorphological and structural sense, it defines floodplains, deltas, or low land strips resulting from a long process of sedimentation and dynamic fluvial accumulation.
• Silting up — The act of depositing alluvium and its result; the natural or technically induced process through which a watercourse deposits sediments, leading to the rising of the riverbed or the covering of land with silt; silting up. As a plural form, it denotes the alluvial attributes or structures characterizing multiple floodplains or hydrographic basins.
• Alluvium — An alternative secondary, archaic, or regional form of the noun 'aluviune'; a sedimentary deposit composed of silt, sand, clay, and detrital gravel, transported by running waters and dropped in areas where the current velocity decreases. In old agricultural documents, the term referred to new strips of fertile land added to riverbanks following seasonal floods.
• 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.