Conflicts
Since the Yarmouthian (Yarmouth) interglacial was named, the stratigraphy of Pleistocene deposits was found to be far more complex then the two glacial tills and one volcanic ash bed on which the Yarmouthian, Kansan, Nebraskan, and Aftonian glacial - interglacial nomenclature was originally based. Detailed research by various geomorphologists and Quaternary geologists demonstrated that the two glacial tills and one ash bed stratigraphic model, on which the Yarmouthian, Kansan, Nebraskan, and Aftonian glacial - interglacial nomenclature was based, was completely wrong. For example, the so-called "Kansan" glacial sediments in which the Yarmouth Soil developed are now known to date to different periods of glaciation depending on where it is examined within the Midwest and other parts of North America. In addition, fission track dating and geochemical analysis demonstrated what was thought to be one volcanic ash layer was actually three separate volcanic ash layers, i.e. the 602,000 year-old Lava Creek B volcanic ash; the 1,293,000 year-old Mesa Falls volcanic ash, and the 2,003,000 year-old Huckleberry volcanic ash. Thus, the basic assumptions, on which the Yarmouthian (interglacial), Kansan (glacial), Aftonian (interglacial), and Nebraskan (glacial) nonmenclature was originally defined was found to be lacking any scientific basis. As a result, the Yarmouthian (interglacial), Kansan (glacial), Aftonian (interglacial), and Nebraskan (glacial) nonmenclature was abandoned by Quaternary geologists North America and merged into the Pre-Illinoian Stage.
Read more about this topic: Yarmouthian (stage)
Famous quotes containing the word conflicts:
“They [parents] can help the children work out schedules for homework, play, and television that minimize the conflicts involved in what to do first. They can offer moral support and encouragement to persist, to try again, to struggle for understanding and mastery. And they can share a child’s pleasure in mastery and accomplishment. But they must not do the job for the children.”
—Dorothy H. Cohen (20th century)
“I would rather be the child of a mother who has all the inner conflicts of the human being than be mothered by someone for whom all is easy and smooth, who knows all the answers, and is a stranger to doubt.”
—D.W. Winnicott (20th century)
“Not all conflicts between siblings are good, of course. A child who is repeatedly humiliated or made to feel insignificant by a brother or sister is learning little except humiliation and shame.”
—Lawrence Kutner (20th century)