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  2. List of rivers by age - Wikipedia

    en.wikipedia.org/wiki/List_of_rivers_by_age

    This river may predate the break-up of western Gondwana as an extension of a proto-Congo river system, 200 Mya during the Jurassic. Ohio: 3~2.5 Mississippi River: Formed when the Laurentide Ice Sheet dammed the north flowing Teays River during the Pre-Illinoian glaciation. The drainage area of the Teays could no longer drain to the north, and ...

  3. Geological history of North America - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of...

    The first major unit of time it contained was the Cambrian period of the Paleozoic era. [6] At the time, Earth's continents were in a very different arrangement and were generally smaller than they are today. The southeastern part of the US was connected to South America and Africa and located in the polar latitudes of the southern hemisphere.

  4. Laurentide ice sheet - Wikipedia

    en.wikipedia.org/wiki/Laurentide_ice_sheet

    At times, the ice sheet's southern margin included the present-day sites of coastal towns of the Northeastern United States, and cities such as Boston and New York City and Great Lakes coastal cities and towns as far south as Chicago and St. Louis, Missouri, and then followed the present course of the Missouri River up to the northern slopes of ...

  5. River valley civilization - Wikipedia

    en.wikipedia.org/wiki/River_valley_civilization

    A river valley civilization is an agricultural nation or civilization situated beside and drawing sustenance from a river. A river gives the inhabitants a reliable source of water for drinking and agriculture. Some other possible benefits for the inhabitants are fishing, fertile soil due to annual flooding, and ease of transportation.

  6. Geologic time scale - Wikipedia

    en.wikipedia.org/wiki/Geologic_time_scale

    An era is the second largest geochronologic time unit and is equivalent to a chronostratigraphic erathem. [ 14 ] [ 13 ] There are ten defined eras: the Eoarchean , Paleoarchean , Mesoarchean , Neoarchean , Paleoproterozoic , Mesoproterozoic , Neoproterozoic , Paleozoic , Mesozoic and Cenozoic , with none from the Hadean eon.

  7. Timeline of environmental history - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_environmental...

    Exceptional precipitation absence in northern hemisphere exacerbated by human activities [citation needed] causes the Dust Bowl drought of the US plains and the Soviet famine of 1932–1933 (harsh economic damage in US and widespread death in USSR). 1939 1945 World War II, with heavy bombardment, genocide, and explosions.

  8. Human history - Wikipedia

    en.wikipedia.org/wiki/Human_history

    The early modern period is the era following the European Middle Ages until 1789 or 1800. [ q ] A common break with the medieval period is placed between 1450 and 1500 which includes a number of significant events: the fall of Constantinople to the Ottoman Empire , the spread of printing and European voyages of discovery to America and along ...

  9. Exploration of North America - Wikipedia

    en.wikipedia.org/wiki/Exploration_of_North_America

    In 1833, his exploring party discovered a route along the Humboldt River across present-day Nevada, ascending the Sierra Nevada following the Carson River and descending via Stanislaus River drainages to Monterey. His return route across the southern Sierra was via Walker Pass, named after Walker by John Charles Fremont.