enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Chalk stream - Wikipedia

    en.wikipedia.org/wiki/Chalk_stream

    Chalk streams are rivers that rise from springs in landscapes with chalk bedrock. Since chalk is permeable, water percolates easily through the ground to the water table and chalk streams therefore receive little surface runoff. As a result, the water in the streams contains little organic matter and sediment and is generally very clear. [c]

  3. Chalk - Wikipedia

    en.wikipedia.org/wiki/Chalk

    Chalk is so common in Cretaceous marine beds that the Cretaceous Period was named for these deposits. The name Cretaceous was derived from Latin creta, meaning chalk. [10] Some deposits of chalk were formed after the Cretaceous. [11] The Chalk Group is a European stratigraphic unit deposited during the late Cretaceous Period.

  4. Cretaceous - Wikipedia

    en.wikipedia.org/wiki/Cretaceous

    The Cretaceous is justly famous for its chalk; indeed, more chalk formed in the Cretaceous than in any other period in the Phanerozoic. [27] Mid-ocean ridge activity—or rather, the circulation of seawater through the enlarged ridges—enriched the oceans in calcium ; this made the oceans more saturated, as well as increased the ...

  5. Chalk Group - Wikipedia

    en.wikipedia.org/wiki/Chalk_Group

    The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur across the wider northwest European chalk 'province'.

  6. Niobrara Formation - Wikipedia

    en.wikipedia.org/wiki/Niobrara_Formation

    Niobrara Chalk was weathered and opalized in the Valentine phase of the Ogallala Formation. The Niobrara Formation / ˌ n aɪ. ə ˈ b r ær ə /, also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late ...

  7. Yorkshire Wolds - Wikipedia

    en.wikipedia.org/wiki/Yorkshire_Wolds

    The hills are formed from a series of pure marine limestones formed during the Cretaceous period, known collectively as the Chalk Group.The outcrop has the form of an arc running north from Ferriby on the Humber estuary west of Hull northwards past Market Weighton to the Malton area where it swings eastwards towards the North Sea coast between Filey and Bridlington.

  8. Rügen chalk - Wikipedia

    en.wikipedia.org/wiki/Rügen_Chalk

    The chalk and water mixture, also called Kreidemilch or Kreidetrübe, was passed through separation tanks where the finer impurities, the Grand, settled out. The chalk suspension freed from the grand then collected in the settling basin, where the still-suspended particles settled out and accumulated into a layer about 30 cm thick. The ...

  9. Geology of the Isle of Wight - Wikipedia

    en.wikipedia.org/wiki/Geology_of_the_Isle_of_Wight

    Geological map of the Isle of Wight. The geology of the Isle of Wight is dominated by sedimentary rocks of Cretaceous and Paleogene age. This sequence was affected by the late stages of the Alpine Orogeny, forming the Isle of Wight monocline, the cause of the steeply-dipping outcrops of the Chalk Group and overlying Paleogene strata seen at The Needles, Alum Bay and Whitecliff Bay.