Sedimentary Rocks Essays (181 words) - Petrology, Stratigraphy

Sedimentary Rocks 1)a. The first stated that sedimentary rocks are laid down in a horizontal manner, and the second stated that younger rock units were deposited on top of older rock units. b. The idea that natural geologic processes were uniform in frequency and magnitude throughout time, an idea known as the principle of uniformitarianism. c. In 1815 Smith produced a geologic map of England in which he successfully demonstrated the validity of the principle of faunal succession. This principle simply stated that fossils are found in rocks in a very definite order. This principle led others that followed to use fossils to define increments within a relative time scale. 2) 3) a. 540 the oldest animal fossils 1700 approximate origin of Eukaryotes 2000 transition oxygen atmosphere 3600 oldest known fossil 3700 oldest known rocks b. The time that humans have been on the earth would be erased. 4) a. 4.5 to 3.8 billion years ago b. The Earth and other planets would have been molten at the beginning of their histories. Solidification of the molten material into rocks happened as the Earth cooled. Philosophy