Drift (geology)
As sediment is referred to in the geosciences, the rock material that was transported by a glacier, in ecology (including limnology ) and not the floating of a stream transported to his reason solids in the water column in hydraulic engineering.
Technical term of Geosciences
In geology and geography of the definition of the attachment is limited to glaciogenic sediments. The deposited by glaciers rock material forms in the unconsolidated state of glacial till ( karbonathaltig ) and clay ( from carbonates ) or converted to solid rock, tillites. The coarser material within these deposits is as bedload (English: glacial erratic boulder ) refers. It has as a result of Eistranports often characteristic scarring (glacier scrapes ) and is then called gekritztes attachment. Transported by glacial sediment is usually only rounded edges. Large boulders (more than 1 m³) is called boulders.
The customer attachment is intensely concerned with the individual rock whose origin and history of origin. It shall distinguish between Sedimentärgeschieben ( from stone deposits ) and crystalline Slide ( from igneous and metamorphic rocks ).
When boulders of northern European origin are mostly igneous rocks, such as granite, or metamorphic rocks. Sedimentary rocks are also due to lower resistiveness, much less frequently. Typical rocks are:
- Åland Rapakiwi
- Brown Baltic quartz porphyry
- Bredvads porphyry
- Dalarna Sandstone
- Dolomite
- Gray limestone
- Kalmar Sandstone
- Rhombenporphyr
- Red limestone
- Scolithen Sandstone
- Småland granite
A special category within the sediment form the Leitgeschiebe whose area of origin is very limited and precisely known. They thus allow conclusions about the distance traveled by ice road. Typical Leitgeschiebe for the northern central Europe originate from Scandinavia, for example, the rhombic porphyries from the area around Oslo or the Åland Rapakiwi of the Åland Islands in the Baltic Sea. In the Alps, for example, the Julier Granite is a Leitgeschiebe for during the ice age also brimmed with today's catchment area also Inngletscher ( transfluency ).
The salvaged from Scandinavian Sedimentärgeschieben fossils are mostly produced layer sequences that are not digested in Germany. They are therefore valuable for collectors. These include trilobites, brachiopods and Orthoceras ( nautiloid ) from rocks of the Paleozoic. Many fossil species are known so far only from attachments, including the famous Xenusion from the Cambrian [Note 1].
In the northern central Europe accounted for almost all sediment types from Scandinavia or the Baltic Sea basin, as streak in northern Germany, Denmark and northern Poland hard rocks only in a few small areas on the surface. Sediment from these deposits are located mainly in the vicinity of upcoming. Such so-called local attachments are the Holsteiner rock, the Sternberg cake [Note 2] or the Heiligenhafen rock.
Lying on the surface sediment were ground by the wind verdrifteten sand. There were the characteristic wind Kanter, particularly numerous in Altmoränenland.
Using glacial sediment
Glacial boulders are used from time immemorial as a building block in northern central Europe. Your use began in prehistoric times with the construction of megalithic tombs. In the Middle Ages numerous churches, but also secular buildings built from boulders (field stones). In modern times, it was used to pave the streets. Currently there are boulders in the garden and landscaping popular. Since 1990 also created numerous boulder gardens, which featured attachment are issued publicly.
Technical term of Limnology and Water Engineering
In hydraulic and limnology are transported by flow solids, sliding, rolling or jumping move on the river bottom, referred to as bedload or towing cargo. The term refers primarily - not exclusively - on such fluvial sediments that are currently in the transport process, or who have come temporarily to rest. The sediment mass is denoted by the term bed load transported per second in a one -meter-wide stretch of water ( in ).
The similar in meaning geoscientific concept gravel refers more contrast - also not exclusively - on durable deposited fluvial sediment.
The sediment load of a river is next to the bed load from the floating suspension transported cargo and freight solution. The grain size, which is the border of the sole near- suspended load of sediment is dependent on the flow rate of the river bed, which in turn brings certain balance of forces of gravity and inertia with it. It has been shown that the Froude number, which describes these conditions, approximately describes the limit at which a particle behaves like sediment (< 19) or is suspended carried by water (> 19). Due to the mutual friction of pebbles river boulders are well rounded to very well and are downriver getting smaller.