Facies in the context of Member (geology)

A marine regression is a geological process occurring when areas of submerged seafloor are exposed during a drop in sea level. The opposite event, marine transgression, occurs when flooding from the sea covers previously-exposed land.

A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize it.

Units must be mappable and distinct from one another, but the contact need not be particularly distinct. For instance, a unit may be defined by terms such as "when the sandstone component exceeds 75%".

Thickness in geology and mining refers to the distance across a packet of rock, whether it be a facies, stratum, bed, seam, lode etc.

Thickness is measured at right angles to the surface of the seam or bed and thus independently of its spatial orientation. The concept of thickness came originally from mining language, where it was used mainly to indicate the workability of seams. It has since become an established term in earth science, for example in geology, for the depth of sedimentary rocks, in hydrogeology for the vertical extent of groundwater – i.e. the distance from the base of the groundwater layer to its surface – or in soil science for the vertical extent of soil horizons.

Red beds (or redbeds) are sedimentary rocks, typically consisting of sandstone, siltstone, and shale, that are predominantly red in color due to the presence of ferric oxides. Frequently, these red-colored sedimentary strata locally contain thin beds of conglomerate, marl, limestone, or some combination of these sedimentary rocks. The ferric oxides, which are responsible for the red color of red beds, typically occur as a coating on the grains of sediments comprising red beds. Classic examples of red beds are the Permian and Triassic strata of the western United States and the Devonian Old Red Sandstone facies of Europe.

Upper Middle Rhine Valley is the 65 km (40 mi) southern section of the Middle Rhine between Koblenz and Rüdesheim in the states of Rhineland-Palatinate and Hesse in Germany. It was added to the UNESCO list of World Heritage Sites in June 2002 because of its beauty as a cultural landscape, its importance as a route of transport across Europe, and the unique adaptations of the buildings and terraces to the steep slopes of the gorge.

The region's rocks were laid down in the Devonian period and are known as Rhenish Facies. This is a fossil-bearing sedimentary rock type consisting mainly of slate. The rocks underwent considerable folding during the Carboniferous period. The gorge was carved out during a much more recent uplift to leave the river contained within steep walls 200 m (660 ft) high, the most famous feature being the Loreley.

The Würm glaciation or Würm stage (German: Würm-Kaltzeit or Würm-Glazial, also Würmeiszeit or Würmzeit; cf. ice age), commonly referred as the Würm (often spelled "Wurm"), was the last glacial period in the Alpine region. It is the youngest of the major glaciations of the region that extended beyond the Alps themselves. Like most of the other ice ages of the Pleistocene epoch, it is named after a river, in this case the Würm in Bavaria, a tributary of the Amper.

The Würm ice age can be dated to about 115,000 to 11,700 years ago. Sources differ about the dates, depending on whether the long transition phases between the glacials and interglacials (warmer periods) are allocated to one or other of those periods. The average annual temperatures during the Würm ice age in the Alpine Foreland were below −3 °C (today +7 °C). That has been determined from changes in the vegetation (pollen analysis), as well as differences in the facies.