August 4, 2012 - Happy Birthday, Johann Gottlob Lehmann

He went from Prussia to Russia as he studied rocks and minerals.

Born on this date in 1719, Lehmann was a German geologist. He studied mining practices in the German states of Saxony and Prussia, and he eventually became a professor of chemistry in Russia, where he also directed the imperial museum.

But Lehmann is best known as one of the founders of stratigraphy.

Many rocks are formed in shallow seas and lakes, as sand and clay particles, tiny rocks, bones and shells of dead creatures, and other sediments sink to the bottom of still or slow-moving water. Over the years, these sediments are crushed together by the weight of newer particles and, of course, the water itself—crushed together so hard that the sediments form a rock.

Examples of such sedimentary rocks include:

and conglomerate.

Lehmann and other pioneers of stratigraphy were able to study and describe various layers of rock, which can give rock a striped look. Sedimentary rocks have since become very important in determining time scales and figuring out what was happening on the earth, both with landforms and lifeforms, in the far, far past.

Striped rocks=beautiful rocks.
The Grand Canyon is made from eroded
sedimentary rock.

Also on this date:

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