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North America inland sea

  1. Jun 30, 2015 #1
    i went to see 'San Andreas' last weekend. it's rather cheesy movie. but it got me interested in the San Andreas fault. after some look online, I realized that at one time there's an inland sea existed between Rockies in the west and Appalachian mountains in the east. but wiki shows it as waterway instead of an inland sea.

    so did an inland sea exist at some point?
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  3. Jun 30, 2015 #2
  4. Jun 30, 2015 #3


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    Depends on what you consider an inland sea.

    In the Cretaceous period, much of the American west east of the Rockies was under water in what is now called the Western Interior Seaway:


    This seaway stretched from what is now the Gulf of Mexico to the Arctic Ocean.

    In more recent times, geologically speaking, various large bodies of water existed in the West, and some have left traces of their existence today.

    The Great Salt Lake in Utah is what's left of a larger body of water called Lake Bonneville:



    The Glacial periods also created large lakes in the West, and Lake Agassiz covered much of the Dakotas and extended into southern Canada:


    This article discusses various ancient bodies of water around the globe:


    I'm sure you can Google up many more if you choose.
  5. Jun 30, 2015 #4
    This is where I do much of my work.

    Remember that such features are quite variable. 'Seas', especially those within continents are quite variable over time. Shore lines can change hundreds of kilometers over just a few thousand years. Thus when we are doing work in terrestrial deposits there are often marine layers.
  6. Jun 30, 2015 #5


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  7. Jun 30, 2015 #6
    I guess the Mediterranean sea is the best example of an inland sea at the present time.
    It is connected with the Atlantic, but only just, and a lot of it is very shallow.
  8. Jun 30, 2015 #7


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    The Mediterranean is actually a body of water surrounded by parts of three continents: Europe, Africa, and Asia.

    As for it being very shallow, the average depth of the Mediterranean is about 1500 meters, and its deepest point is more than 5200 meters.


    Although it is connected to the Atlantic Ocean by the narrow Straits of Gibraltar, some consider the Mediterranean to be an arm of the Atlantic.
  9. Jun 30, 2015 #8


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    The Mediterranean Sea has an average depth of 1500 m, and the majority of it is over 1000 m deep. When I look at a contour map of it, it is hard to see how you conclude that "a lot of it is very shallow". Also, I don't think it is a good example of an inland sea. The inland sea in North America was over continental crust, whereas the Mediterranean Sea is predominantly oceanic crust.
  10. Jul 1, 2015 #9
    Yes, there are many 'seas'. A sea is not a geologic term.

    The inland sea (what we hear call the Bearpaw Sea) was internal to the American plate. Most other seas are ocean based between plates. Plate tectonics means ever changing position of land masses so these types of bodies of water are not the same.

    During most of the Upper Cretaceous, conditions were stable in what is now North America. Extremely stable ecologically...especially with the absence of major ice ages. There is a good geologic record of the ebb and flow of the inland sea.
  11. Jul 1, 2015 #10


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    hmmmm sorta .... its very tidally connected with the Atlantic, so I personally wouldn't put it in that class

    for real inland seas, look at the Black Sea, Caspian Sea as better examples. Particularly the Caspian Sea ... totally landlocked

  12. Jul 2, 2015 #11
    that's exactly what i have in mind about inland sea. it seems inaccurate to describe the one existed in north america as inland sea, wiki got it right, it's a water pathway that connected arctic with Gulf of Mexico.
  13. Jul 2, 2015 #12
    Wiki isn't a geologic publication. When we do research we quote accepted geologic publications.

    There is no definition of an 'inland sea' other than how 'you' define it. As every professor drums into their students from day one...define your terms. An inland sea can be anything from a bathtub to Hudson Bay...it's all in the definition and then, once defined, use that definition consistently.
  14. Jul 3, 2015 #13

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    Did you read that wikipedia article? It starts with (emphasis mine) "The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, and the North American Inland Sea) was a large inland sea ..."

    You are thinking of a closed, or endorheic, body of water. There aren't nearly as many of those are there are inland seas, bodies of water connected to the oceans that lie over continental crust and that are somewhat isolated from the oceans. Inland seas such as the Inland Sea of Japan, the Baltic, the Adriatic, the Aegean, and many others are very interesting from biological, geographical, and archeological perspectives.
  15. Jul 4, 2015 #14
  16. Jul 4, 2015 #15
    Also, There is a short Wikipedia article on Lake Lahontan with some good references to get you going. It existed in the Pleistocene.
  17. Jul 6, 2015 #16
    If you think about it, most places with limestone in the central US were once under saltwater.
    I think it is fairly easy to find sea fossils from Texas to Ohio, and most places between.
  18. Jul 6, 2015 #17
    Many of those deposits were from marine oceans that existed when there were other configurations of continental plates. However, even those had the potential for inland seas whether we now have evidence of them or not. What's covering the Earth's surface is quite dynamic on a geologic time scale.
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