Origin
The generally accepted theory for the origin of lithographic and sublithographic limestones is that they were formed in shallow stagnant hypersaline and anoxic lagoons. The combination of mild hypersalinity and low oxygen content is believed to have inhibited the formation of microbial mats and prevented the invasion of bottom dwelling organisms. Microbial mats and bottom dwelling organisms would have left fossils, and bottom dwelling organisms would have churned the accumulating sediment, producing a less homogeneous rock. Stagnancy was required to avoid churning or sculpting of the sediment by currents or wave action.
Read more about this topic: Lithographic Limestone
Famous quotes containing the word origin:
“Our theism is the purification of the human mind. Man can paint, or make, or think nothing but man. He believes that the great material elements had their origin from his thought.”
—Ralph Waldo Emerson (1803–1882)
“For, though the origin of most of our words is forgotten, each word was at first a stroke of genius, and obtained currency, because for the moment it symbolized the world to the first speaker and to the hearer. The etymologist finds the deadest word to have been once a brilliant picture.”
—Ralph Waldo Emerson (1803–1882)
“Art is good when it springs from necessity. This kind of origin is the guarantee of its value; there is no other.”
—Neal Cassady (1926–1968)