Tucson Citizen.com
Wry Heat - by Jonathan DuHamel

Posts Tagged ‘Geology’

Book Review – Louis Agassiz, a biography by Christoph Irmscher

Monday, January 28th, 2013

I first heard of Louis Agassiz (1807-1873) in my beginning geology courses. A Pleistocene lake, Lake Agassiz, which covered parts of Manitoba, Ontario, Saskatchewan, North Dakota, and Minnesota, was named after Agassiz posthumously because of Agassiz’s research on glaciers in the Swiss Alps.

Aggasiz was born in Switzerland and educated there and in Germany, receiving a PhD. in 1829 in natural science, and a Doctorate in surgery and medicine in 1830, the later to please his Calvinist father.

In 1846 he moved to America where he became a professor of Zoology at Harvard, founded the Anderson School of Natural History near Cap Cod (one of the first coed colleges) that eventually became Woods Hole Oceanographic Institution. Agassiz was a passionate collector and established what would become the Museum of Comparative Zoology in Cambridge, Massachusetts. He advertized far and wide for specimens, living or dead.

According to Irmsher, Agassiz was a complex man, a great friend to Henry Wadsworth Longfellow and an arch-rival to Charles Darwin. He was a passionate scientist and part P.T. Barnum. And he had a dark side.

Irmsher writes that Agassiz’s story is “riven with the contradictions of a man who wanted to come across as both rigorously professional and unrelentingly popular, a man who believed that science practiced with due diligence could clear up not only the little problems that confounded the specialists but also the whole cosmic puzzle itself. Agassiz was one of the first to establish science as a collective enterprise. Yet he insisted on putting his own personal stamp on anything that came out of the museum he had founded and forbade his assistants to claim credit for any part of their own research done on company time. He was an ardent advocate of abolition, yet he also believed in the racial inferiority of blacks.”

Agassiz’s study of glaciers and fossils lead him to reject Darwin’s new theory of evolution. Rather, Agassiz was somewhat of a Creationist, but not as the term is currently used. Agassiz believed not in continuous evolution, but a series of creation events, in “oscillations,” where ice ages killed off everything and God created and recreated life anew.

Agassiz published over 400 books and scientific articles and was one of the first to propose that Europe and North America were once covered by glaciers. He was, however, a great proponent of field work, “study nature, not books.” He was also the consummate lecturer and his lectures were not confined to the classroom. His “popularity in America transcended class as well as regional boundaries.”

Irmsher spins an interesting story of a complex man based largely upon abundant correspondence from Agassiz, his contemporaries, and his wife and sister.

One of Agassiz’s great strengths was his ability to explain science to the layman. Irmsher writes in the epilogue, “as Louis Agassiz drifts into the sunset of this narrative, it is worth remembering how his struggles, problems, and aspirations are still with us. Yes, we haven’t moved beyond his biases and blindnesses as much as much as we would like to think we have, but that isn’t all. In my view, Louis Agassiz was never more provocative than when he argued science ought to be part of the general fabric of society.” I agree. More emphasis on science is needed in general education.

If you are interested in the history of science, its development and its characters, you will be interested in the story of Louis Agassiz.

The book is available is published by Houghton Mifflin Harcourt and is available at Amazon as a hardcover book (to be released Feb. 5) and a Kindle edition. It is also available from Barnes & Noble.

Arizona Geological Survey celebrates its 125th anniversary

Friday, January 4th, 2013

Interest in geology and mining is an integral part of Arizona history. In 1888, the Arizona Territorial Legislature appointed John Blandy as Territorial Geologist. From that point, what became AZGS grew under several names from the University of Arizona Bureau of Mines (1893 – 1915), Arizona Bureau of Mines (1915 – 1977), and the Arizona Bureau of Geology and Mineral Technology (1977 – 1988), to the Arizona Geological Survey (1988 to present).

To help celebrate this anniversary, AZGS has created a special webpage:

http://www.azgs.az.gov/125th-anniversary-azgs.shtml

Included on that page is “Geosnaps – Image of the Day” a new photo every day depicting some aspect of Arizona geology or mining history.

Some other features will include:

Arizona Mining Review – a monthly webinar hosted by State Geologist Lee Allison to discuss Arizona mining – past, present and future.

Release of new & old geologic products bearing the 1888 – 2013, 125th anniversary logo.

Timeline graphic demarcating milestones in the history of Arizona geology.

A retrospective review on the state of geology of Arizona ca. 1888. Arizona Geology Magazine 125th year anniversary issue.

125th anniversary field trip(s).

Beginning January 23, there is the “Arizona Mining Review” with news and updates on the state of Arizona mining. Each month they will introduce a new topic and select a format – featured guest, panel discussion, Q&A session – to draw the most out of the topic.

Visit the anniversary site often.

 

 

Landscape evolution in SE Arizona – a river runs through it

Monday, December 31st, 2012

The physiography of southeastern Arizona is characterized by long, thin mountain ranges separated by broad, fault-bounded valleys. This physiography, which is unique on the planet, is the result of crustal extension that occurred between 8- to 12 million years ago.

 

 

 

 

 

 

 

 

 

 

 

The story of the evolution of SE Arizona is the subject of a featured article in the new Fall-Winter 2012 issue of Arizona Geology magazine, published by the Arizona Geological Survey. The paper is “Post-Tectonic Landscape Evolution in Southeastern Arizona: When Did a River Start to Run Through It?” by Matthew C. Jungers.

Initially, the basins had internal drainage and were not connected. Jungers’ story shows how geologic forces gradually connected the basins and how the Gila-Santa Cruz-San Pedro river system developed. The article also describes how he figured it out.

The graphic below shows the sequence of events according to Jungers:

 

 

 

 

 

 

 

His figure caption reads:

“Figure 2. Final stages of the Basin and Range disturbance. (A) Structural basins were filled with sediment, and most basins were still internally drained. (B) Following the cessation of extensional tectonics in the region, basins continued to fill with sediment and faults were buried. Basins began to integrate with the main stem Gila River via a combination of basin spillover and headward drainage capture. (C) Following integration with an adjacent basin, sedimentary fill was incised as its basin adjusted to a new, lower base level. (D) As a new, through-flowing drainage network was established, integrated basins graded to the Gila River. The shift to an oscillating climate in the Quaternary may be preserved in flights of terraces that record alternating periods of floodplain stability followed by rapid incision. Figure adapted from Menges and Pearthree, 1989.”

 

Read the full article here.

For more geology stories, see my Article Index page.