File:Ugab river.jpeg

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English: False color satellite image of a part of the Ugab River valley, Namibia. – The Ugab river is an ephemeral river that only flows above the surface of its sandy bed a few days each year, but its subterranean water is an important resource for species in the Damaraland region of northern Namibia, including the rare desert elephant.
This contrast-enhanced false color image has the Landsat band combination 7-5-4, which means that the red (3), green (2), and blue (1) bands that comprise true color images are replaced by two mid-infrared (7 and 5) and one near-infrared (4) bands. This band combination is appropriate for mapping the surficial geology. The Ugab River here crosses the outcrop of a geological unit which is called “Zerrissene Turbidite System”. It is made up of folded, low grade metamorphosed Neoproterozoic sedimentary rocks which can be subdivided into 5 formations.[1] Most of these formations are quite good identifiable in the false color image: The Zebrapüts Formation (greyish to yellowish), the Brandberg West Formation (a thin violet band, too thin to be clearly visible in the western part of the area, but apparently with larger outcrop area in the east due to very narrow folding), the Brak River Formation (yellowish to dark brown), the Gemsbok River Formation (the broader violet bands), and the Amis River Formation (orange to reddish-brown). The yellowish, brownish and reddish colors are indicative of siliciclastic rocks (claystones and sandstones, incl. “greywacke”) while violet is indicative of carbonates.

Deutsch: Falschfarben-Satellitenaufnahme eines Teils des Tals des Ugab River, Namibia. – Der Ugab ist ein periodisch wasserführender Fluss, der nur ein paar Tage im Jahr an der Oberfläche seines sandigen Bettes fließt, jedoch ist sein unterirdisches Wasser eine bedeutende Ressource für die Arten im Damaraland, einschließlich dem seltenen Wüstenelefant.
Diese kontrastverstärkte Falschfarbenaufnahme besitzt die Landsat-Kanalkombination 7-5-4, was bedeutet, dass der Rot- (3), Grün- (2) und Blaukanal (1), aus denen Echtfarbenbilder zusammengesetzt sind, durch zwei mittlere Infrarot- (7 und 5) und einen Nah-Infrarotkanal (4) ersetzt wurden. Diese Kanalkombination ist für die Kartierung der Oberflächengeologie geeignet. Der Ugab River durchquert hier den Ausbiss einer geologischen Einheit, die „Zerrissene Turbidite System“ genannt wird. Sie ist aus gefalteten, niedriggradig metamorphen neoproterozoischen Sedimentgesteinen aufgebaut, die in 5 Formationen untergliedert werden kann.[1] Die meisten dieser Formationen können recht gut in der Falschfarbenaufnahme identifiziert werden: Die Zebrapüts-Formation (gräulich bis gelblich), die Brandberg-West-Formation (ein dünnes violettes Band, zu geringmächtig, um im Westen des Gebietes deutlich erkennbar zu sein, aber anscheinend mit größerer Ausbissfläche im Osten aufgrund sehr enger Faltung), die Brak-River-Formation (gelb- bis dunkelbraun), die Gemsbok-River-Formation (die etwas breiteren violetten Bänder) und die Amis-River-Formation (orange bis rötlich-braun). Die gelblichen, bräunlichen und rötlichen Farbtöne zeigen siliziklastische Gesteine an (Tonsteine und Sandsteine, einschließlich „Grauwacke“), während Violett Karbonatgesteine anzeigt.
  1. ↑ a b Roger Swart (1990): The Sedimentology of the Zerrissene Turbidite System, Damara Orogen, Namibia. PhD-Thesis. Rhodes University, Grahamstown (PDF 14 MB), pp. 1–8, fig. 1.5.
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Source USGS Landsat Project Image Gallery: Ugab River, Namibia at the Wayback Machine, cf. Our Earth as Art – Ugab River at the Wayback Machine
Author NASA/USGS (Landsat 7 data)
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(Reusing this file)		 public domain

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Public domain This file is in the public domain in the United States because it was solely created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See Template:PD-USGov, NASA copyright policy page or JPL Image Use Policy.)
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