were criticized because he could not explain what had happened to Werner's such an immense volume of water needed to form all "primitive rocks," and because he insisted that lava flows were precipitated from water. geologists showed the volcanic origin of lava flows. These were the Other Plutonists, named for the Roman god of the underworld. Plutonists said that "fire" or heat, rather than water, was involved in the origin of "primitive" igneous rocks. Hutton (1726-1797) was a prominent Plutonist who disagreed with Werner. James UNCONFORMITIES An unconformity is an ancient surface of erosion (or non-deposition), separating older rocks from younger rocks. If the older rocks are folded or tilted, the unconformity is referred to as an angular unconformity. James Hutton recognized the significance of the unconformity at Siccar Point in Scotland. HUTTON'S UNIFORMITARIANISM 1.Saw Earth as a dynamic, ever changing place where rocks and mountains form slowly, and are slowly weathered and eroded. 2.Recognized that "the present is the key to the past." 3.Recognized uniform natural laws (physical & chemical laws) govern geologic processes, later this view was called uniformitarianism. 4.Uniform natural laws govern weathering, erosion, glacial movement, earthquakes, volcanic eruptions, and the transport of sediment by moving water. Limitations on uniformitarianism: Some events which occurred in the past, and left a record in the rocks, ARE NOT OCCURRING TODAY, or have not occurred during human history. These include: meteorite impacts Huge volcanism Extensive glacial ice sheets accompanied by much lower sea levels Large in atmospheric chemistry - original atmosphere lacked oxygen, Differences so chemical process acting in the weathering environment did not include oxidation UNIFORMITARIANISM ACTUALISM geologists prefer to use the term actualism, to emphasize the importance of Many natural laws to the concept of uniformitarianism. is the principle that natural laws (physical and chemical laws) governing Actualism past and present processes on Earth have been the same. PRINCIPLE OF FOSSIL SUCCESSION Smith (1769–1839) was an English surveyor and civil engineer who was William working to site canals to transport coal in England. saw that layers of rocks occurred in a definite order, and that rock units could He be differentiated on the basis of the unique set of fossils they contain. PRINCIPLE OF FOSSIL SUCCESSION
Werner's were criticized because he could not explain what had happened to such an immense volume of water needed to form all "primitive rocks," and because he insisted that lava flows were precipitated from water. Other geologists showed the volcanic origin of lava flows. These were the Plutonists, named for the Roman god of the underworld. Plutonists said that "fire" or heat, rather than water, was involved in the origin of "primitive" igneous rocks. James Hutton (1726-1797) was a prominent Plutonist who disagreed with Werner. UNCONFORMITIES An unconformity is an ancient surface of erosion (or non-deposition), separating older rocks from younger rocks. If the older rocks are folded or tilted, the unconformity is referred to as an angular unconformity. James Hutton recognized the significance of the unconformity at Siccar Point in Scotland. HUTTON'S UNIFORMITARIANISM 1.Saw Earth as a dynamic, ever changing place where rocks and mountains form slowly, and are slowly weathered and eroded. 2.Recognized that "the present is the key to the past." 3.Recognized uniform natural laws (physical & chemical laws) govern geologic processes, later this view was called uniformitarianism. 4.Uniform natural laws govern weathering, erosion, glacial movement, earthquakes, volcanic eruptions, and the transport of sediment by moving water. Limitations on uniformitarianism: Some events which occurred in the past, and left a record in the rocks, ARE NOT OCCURRING TODAY, or have not occurred during human history. These include: Huge meteorite impacts Extensive volcanism Large glacial ice sheets accompanied by much lower sea levels Differences in atmospheric chemistry - original atmosphere lacked oxygen, so chemical process acting in the weathering environment did not include oxidation UNIFORMITARIANISM ACTUALISM Many geologists prefer to use the term actualism, to emphasize the importance of natural laws to the concept of uniformitarianism. Actualism is the principle that natural laws (physical and chemical laws) governing past and present processes on Earth have been the same. PRINCIPLE OF FOSSIL SUCCESSION William Smith (1769–1839) was an English surveyor and civil engineer who was working to site canals to transport coal in England. He saw that layers of rocks occurred in a definite order, and that rock units could be differentiated on the basis of the unique set of fossils they contain. PRINCIPLE OF FOSSIL SUCCESSION
Ch02%20Early%20Geologists%20Tackle%20History%20Mysteries%20Notes.docx