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The Silurian (/ s ɪ ˈ lj ʊər i. ən, s aɪ-/ sih-LURE-ee-ən, sy-) [8] [9] [10] is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.1 million years ago (), to the beginning of the Devonian Period, 419.62 Mya. [11]
The Silurian hypothesis is a thought experiment, [1] which assesses modern science's ability to detect evidence of a prior advanced civilization, perhaps several million years ago. The most probable clues for such a civilization could be carbon , radioactive elements or temperature variation.
The Salina Group or Salina Formation is a Late Silurian-age, Stratigraphic unit of sedimentary rock that is found in Northeastern and Midwestern North America.Named for its Halite beds, the phrase "Salina Group" was first used as a descriptive term by James D. Dana in 1863.
The Wenlock Epoch (sometimes referred to as the Wenlockian) is the second epoch of the Silurian. It is preceded by the Llandovery Epoch and followed by the Ludlow Epoch. Radiometric dates constrain the Wenlockian between 432.9 and 426.7 million years ago. [5]
In the geological timescale, the Llandovery Epoch (from 443.8 ± 1.5 million years ago to 433.4 ± 0.8 million years ago) occurred at the beginning of the Silurian Period. . The Llandoverian Epoch follows the massive Ordovician-Silurian extinction events, which led to a large decrease in biodiversity and an opening up of ecosyste
The chief geological investigation of the last decade of his life was devoted to the Highlands of Scotland, where he wrongly believed he had succeeded in showing that the vast masses of crystalline schists, previously supposed to be part of what used to be termed the Primitive formations, were really not older than the Silurian period, since ...
Geological map of Wales. Silurian rock is shown in pale green, Ordovician rock in darker green, carboniferous in grey. Other rock formations are also included in the table on the left of the image. The geology of Wales is complex and varied; its study has been of considerable historical significance in the development of geology as a science.
A Silurian reef complex in Gotland. The reef belongs to the Sundre formation, and overlies the Hamra. The geology of Gotland is made up of a sequence of sedimentary rocks of a Silurian age, dipping to the south-east. Gotland is the largest island of Sweden, and is located in the Baltic Sea.