The Earth Story

Geologic Map Day

For the final weekday in ‪#‎earthscienceweek‬ ‪#‎esw2014‬ there is no better story to tell than that of William Smith and this map. Today is Geologic Map day and this is literally the world’s first geologic map.

A geologic map is an interesting concept. To make a map, we go around and figure out what types of rock show up at the surface. That information is then transferred to map format – showing which areas have specific rock types appearing at the surface. If you want to find a rock type somewhere in a country, you look at a geologic map and it can take you there. If you want to find where mineral deposits are found or surface mines should go, a geologic map takes you there.

The first geologic map was created based on fossils by a British Surveyor named William Smith. At the time, people across Europe were beginning to extract, sell, and sometimes classify fossils. While working on canal projects and in coalmines, William Smith realized that certain packages of fossils distinguished certain rocks.

If he found rocks with one set of fossils in one place, they could be matched across the country even if the rocks were slightly different (a shale instead of a siltstone, for example). 

William Smith went through a period of unemployment that allowed him time to travel the country, speaking to fossil hunters and learning the units. In 1815, he published this map of Great Britain, by far the largest area ever put on a geologic map at that time.

Unfortunately, William Smith’s work was soon plagiarized and he fell into poverty before one of his former employers brought him to work at a museum – which is today known as Rotunda – The William Smith Museum of Geology. He was the first recipient of the Wollaston medal – the highest medal given by the Geological Society of London.

This map has been immortalized with a book title: “The Map that Changed the World”.

-JBB

Image credit: http://en.wikipedia.org/wiki/William_Smith_(geologist)#mediaviewer/File:Geological_map_Britain_William_Smith_1815.jpg

Read more: http://www.amazon.com/The-Map-That-Changed-World/dp/0061767905 http://www.ucmp.berkeley.edu/history/smith.html http://earthobservatory.nasa.gov/IOTD/view.php?id=8733 http://earthobservatory.nasa.gov/Features/WilliamSmith/page2.php

ADAM SEDGWICK 'Conflicting falsehoods we can comprehend; but truths can never war against each other.' This fine-looking fellow is British 19th Century geologist Adam Sedgwick. He is considered one of the founders of modern geology, and worked during the ‘Heroic Age’ of Earth Science, when most geological periods were defined. Sedgwick himself proposed the Devonian and Cambrian periods, representing rock deposited 416 – 360 and 360 – 300 million years ago respectively. This alone may strike you as unimpressive – though for geologists it’s sort of a big deal – but consider this! Sedgwick was also the first to distinguish between stratification (layered structures related to bedding of rock), jointing (static fractures in bodies of rock) and slaty cleavage (yes, cleavage is a valid geological term). In some cases these can be incredibly difficult for an amateur geologist to identify. Still not impressed? How about the fact that Sedgwick taught Charles Darwin during his time at Cambridge University, England in the 1830s? Darwin was an assistant on a trip to Wales, during which Sedgwick first proposed the Cambrian as a distinct period. Sedgwick has given his name to the Sedgwick Museum of Earth Sciences in Cambridge, as well as the Sedgwick Prize, given to Cambridge University’s best geology undergraduates.  He remains to this day one of the most important Earth Scientists in the history of the field, both for his own work and his encouragement of his students. ‘I cannot promise to teach you all geology; I can only fire your imaginations.’ -Josh  http://www.ucmp.berkeley.edu/history/sedgwick.html http://www.answers.com/topic/adam-sedgwick http://en.wikisource.org/wiki/Sedgwick,_Adam_(DNB00) Image: http://blog.everythingdinosaur.co.uk/wp-content/uploads/2012/03/adam_sedgwick.jpg

Charles Darwin was wrong Today, February 12th, is the 205th birthday of one of history’s most famous scientists, Charles Darwin, celebrated throughout the world as Darwin Day. Although Charles Darwin is best known for developing the theory of evolution by natural selection, that story is not his only contribution to science. These boulders relate to a different part of Darwin’s voyage on the HMS Beagle; the trip which took him to the Galapagos and drove development of his most famous theory. These boulders are a story Charles Darwin got wrong. I think of myself as a geoscientist. In that sense, I might be able to talk in depth about many topics throughout Earth Science, but my field is still specialized. The kind of common today is fundamentally different from the kind of science done by Darwin, who would have considered himself a “naturalist”; a scientist devoted to the natural world. While on the Beagle, Darwin wasn’t just interested in the biology; he was interested in whatever he saw, including the rocks. These rocks dot the shores near Bahía San Sebastian, south of the Straits of Magellan in Tierra del Fuego. When Charles Darwin saw these rocks, they reminded him of the writings of Dr. Charles Lyell, which described enormous blocks found on the ocean floor off the coasts of Newfoundland. Those rocks arrived via icebergs; floated across hundreds of kilometers of oceans. This process, boulders being carried by icebergs, had even been observed by ships; reports of which Darwin referred to in his writings. Darwin studied the rocks of Tierra del Fuego and realized that far above the shorelines, the rocks contained oceanic fossils. With this fact in hand, he surmised that some geologic forces had lifted the fossils far above the modern day beach. And, since fossils from the ocean could be lifted to great heights, Darwin also surmised that these boulders were dropped on the ocean floor, carried originally by icebergs from Antarctica, and brought up to the surface by later geologic uplift. Boulders like this, erratically strewn throughout the known world, were common and well-known. This process was Darwin’s explanation for their origin. Several years ago, a group led by Dr. Evenson from Lehigh University investigated these exact rocks, matching their shape to those described by Darwin in his writings. You are looking at some of the exact rocks examined by Charles Darwin nearly 2 centuries ago. If the rocks were emplaced as Darwin described, they should be unrelated to the rocks on Tierra del Fuego; they should derive from Antarctica. They should also be unrelated to each other – each iceberg would pluck boulders from a different location on Antarctica. The scientists tested the chemistry of the rocks and noted their geologic context. The boulders in this site are all of a similar composition, identical to a unit found higher up in the nearby mountains (now known as the Beagle granite). There are dozens of boulders at this site, all derived from the same unit. By studying the surrounding geology, the scientists realized that they were standing on a terminal moraine – the place where a prehistoric glacier, born in the mountains above, had ended. By putting together the geologic history…they came to realize…Charles Darwin was wrong. Although Darwin’s observations were interesting, he did not understand one detail at the time. It had yet to be recognized that, over the last several million years, ice sheets had repeatedly formed on the continents and expanded far out of the mountains. Charles Darwin understood the power of ice, but did not recognize that at one time, enormous ice rivers had migrated down from the mountains in Tierra del Fuego, carrying these rocks with them. The kind of data available to us today allows us to tell the story of these rocks in far more detail than could be done in Darwin’s time, but in many ways, this story gives an interesting look into the type of science and thought done by the man at the time. In 1833, Charles Darwin delayed the voyage of the ship to stop and describe a few large chunks of rock found on the shores of a nearly-deserted part of the world, to try to tell their story. As a result, today we can tell the story both of these rocks and of the voyage of the Beagle as well. -JBB Image credit: Henry Patton (creative commons license) http://www.flickr.com/photos/hpatton/3717733679/ Full article: http://www.geosociety.org/gsatoday/archive/19/12/article/i1052-5173-19-12-4.htm

It’s Darwin Day! Yes, today, the 12th of February is a day of celebration for Charles Robert Darwin. Darwin was born on the 12th of February 1809. Initially, Darwin could be described as a geologist; when he was younger he had a substantial rock collection and was knowledgeable in mineralogy and crystallography. His more famous work however, involved zoology. Darwin is famous for establishing that all species of life have derived from common ancestors. He developed the scientific theory of evolution, resulting from what he called “natural selection” – or maybe more publicly known as “survival of the fittest”, in which the struggle for existence was similar to the artificial selection brought on by selective breeding. The drawing in the background of this image is an original sketch of an early phylogenetic tree- showing Darwin’s early theory, which was found in a notebook called “red transmutation notebook B”in 1837. Of course, Darwin later made his theory public with the publication of “The Origin of Species; in which the Tree of Life is included. The tips of the branches in this sketch are representative of species that are still alive today, but the tree also shows species that have existed in the past but are now extinct. Darwin explained this by stating “'From the first growth of the tree, many a limb and branch has decayed and dropped off; and these fallen branches of various sizes may represent those whole orders, families, and genera which have now no living representatives, and which are known to us only in a fossil state.” The lines, or the branches, of the tree are representative of relationships between species. As an example, a current Tree of Life would show a link between Dinosaurs and Birds; it is believed that Birds have evolved from Dinosaurs. The Tree is arranged so that closely related species are found close together. Of course, phylogenetic analysis has come a long way since 1837, but Darwin’s theory of evolution by natural selection is widely accepted and explains the distant origins and fantastic variety of life on Earth. Perhaps my favourite part of this sketch is the words “I think”, Darwin was unafraid to think outside the box in a time when the theory of evolution would be beyond the socially accepted norm. These two words encapsulate the sentiment that it is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change. -Jean For loads more information, take a look over here: http://darwinday.org/

Did you know that the oldest geological map in the world dates to 1150BCE? And is found on the Turin Papyrus, The map was made to display gold deposits in Egypt. The first geological map of England and Wales was made in 1812 by William Smith, and was published in 1815 and was at first overlooked by the geological community. It wasn't until 1831 that he received the recognition he deserved, with the president of the Geological Society of London naming him "The father of English Geology" -LL More Information on William Smith; http://www.ucmp.berkeley.edu/history/smith.html Links for Geological Maps of Australia; http://www.geoscience.gov.au/cgi-bin/mapserv?map=%2Fnas%2Fweb%2Fops%2Fprod%2Fapps_www-c%2Fmapserver%2Fgeoportal-geologicalmaps%2Findex.map&mode=browse&layer=map250&queryon=true USGS Map database; http://ngmdb.usgs.gov/ngmdb/ngmdb_home.html BGS Maps; http://maps.bgs.ac.uk/geologyviewer_google/googleviewer.html Link to High Quality Image; http://www.pesa.com.au/publications/pesa_news/nov_04/images/bookreview/MAP%20OF%20ENGLAND%2BWALES.jpg

JAMES HUTTON: ‘WE FIND NO VESTIGE OF A BEGINNING, NO PROSPECT OF AN END’ James Hutton (3 June 1726 - 26 March 1797), a Scottish farmer and naturalist, is known as one of the fathers and founders of modern geology. His theories on geology came to be known as plutonism and uniformitarianism. Hutton overturned the previously held Neptunism belief system proposed by Abraham Gottlob Werner (that rocks formed from the crystallisation of minerals in the early Earth's oceans), in exchange for the Plutonian theory of decay and renewal. He lived in Edinburgh at the very time it was a bright spot in the Enlightenment, and where the intelligentsia of Europe gathered. He studied medicine and chemistry at the Universities of Edinburgh, Paris, and Leiden, in the Netherlands; then spent fourteen years running two small family farms. Hutton was the first to propose in public and with geological evidence that Earth was much older than 6000 years, which was the common believe at the time (fossils were believed to be the remains of animals that had perished during the Biblical flood). The crux of his argument for renewal came from his discovery, while investigating rocks in Scotland, that granite is an igneous rock. He found granite intruded into sedimentary rocks and saw this as evidence of subterranean fire and heat, further supported by the existence of hot springs and volcanoes. Granite was perceived at this time as a primitive (ie pre-life) rock as it contained no fossils. From his breakthrough on the formation of granite, he then realised that the core of the planet could make new rock, which in turn offset the process of erosion. Hutton realised that rocks were deposited horizontally, and therefore rocks found at non-horizontal angles must have been deposited, and then upturned. Within the unconformities between these rock layers, Hutton surmised great expanses of time must have passed. Hutton proposed an infinite age for the Earth, but in the 18th century nobody could prove the age of the Earth. The final proof of the age of the Earth did not come until the 20th century, when chemists were able to estimate the ages of rocks through rates of radioactive decay; dated to approximately 4.54 billion years old. He also proposed the Theory of Uniformitarianism: geological forces at work in the present day are the same as those that operated in the past. In other words the rates at which processes such as erosion or sedimentation occur today are similar to past rates. This was quite contrary to the belief held at the time that the Earth was formed through catastrophism: the belief that only natural catastrophes, such as the Great Flood, could account for the form and nature of a 6,000-year-old Earth. His book, An Investigation into the Principles of Knowledge, is in 3 volumes and is 2000 pages in length. Within the pages is a chapter on the origin of natural varieties – 50 years before Darwin’s On the Origin of Species were published. People mostly learned of his ideas however through his friend John Playfair, who published Illustrations of the Huttonian Theory of the Earth in 1802. Hutton was accused of being irreligious, but he was actually a deist who believed that the universe's creator had put into place a perfectly self-sustaining system. -TEL Read more about James Hutton here: http://www.james-hutton.org.uk/; http://historyofgeology.fieldofscience.com/2010/06/james-hutton-3-june-1726-26-march-1797.html http://www.todayinsci.com/H/Hutton_James/HuttonJames-Quotations.htm Photo: reproduction of a Watercolor print done by geologist James Hutton entitled: Detailed East-West Section, Northern Granite, Isle of Arran, Strathclyde. http://gallery.usgs.gov/images/07_22_2009/kOf6JVu22C_07_22_2009/large/575016-Theory_of_the_Earth.jpg