Tag Archives: Links

Various Interesting Articles

Thin section photomicrograph of a gabbro, (crossed polarizing filters).  Image credit: Siim Sepp (CC-BY-SA).
Thin section photomicrograph of a gabbro, (crossed polarizing filters). Image credit: Siim Sepp (CC-BY-SA).

There have been a couple of interesting articles I’ve come across recently, which are worth mentioning.

First, Emily Lakdawalla has an excellent summary of the Pluto discoveries from both the American Geophysical Union’s Fall Meeting and the [NASA] Division of Planetary Science meeting. There’s a lot of new stuff there, and it’s pretty exciting.

Second, the Joides Resolution blog (the Joides Resolution is an ocean sediment coring vessel) has a series of posts (1, 2, 3) on geologic thin sections. Not surprisingly, the thin sections pictured are from rocks such as gabbros or sheeted dikes, which are expected in oceanic crust and in ophiolites (oceanic crust exposed on land). There’s a great exposure of the Coast Range Ophiolite just west of Patterson, CA, in Del Puerto Canyon, which is described in a recent blog post by Garry Hayes.

Third, Dave Petley has a great post on The Landslide Blog about the recent landslide in Shenzhen, China. I find landslides fascinating, and always learn something when I read The Landslide Blog.

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Global Warming, and Stephenson Glacier Retreat

Annual global surface temperature difference from the 20th century average.  2014 is the 38th straight year above average.  Image credit: NOAA.
Annual global surface temperature difference from the 20th century average. 2014 is the 38th straight year above average. Image credit: @NOAA.

Two things came to my attention today which are of particular interest.

First, NOAA has announced that globally, 2014 was the warmest year on record, and the 38th straight year of above-average temperatures. Continued action will be needed in 2015 to reverse this trend. Every delay makes fixing the situation more difficult.

Second, Mauri Pelto has written today about the retreat of Stephenson Glacier and the formation of a lagoon on Heard Island. In 1947-1948, when members of the Australian National Antarctic Research Expedition (ANARE) spent 15 months at Heard Island, they found Spit Point, on the southeast side of the island, was only accessible after crossing Stephenson Glacier. Imagery from LANDSAT shows substantial retreat, as do photographs from a 2004 expedition to Heard Island.

Landsat 2010 image, annotated by Mauri Pelto.  Arrows mark the toe of the glacier in 2001 (purple), 2010 (red), and 2013 (yellow).  Additional images are available on Mauri Pelto's blog.
Landsat 2010 image, annotated by Mauri Pelto. Arrows mark the toe of the glacier in 2001 (purple), 2010 (red), and 2013 (yellow). Additional images are available on Mauri Pelto’s blog.

Today, where once Stephenson Glacier met the ocean, there is now Stephenson Lagoon. The toe of the glacier has retreated inland, and to my eye appears to have moved about 4 km. With a warming at Atlas Cove of 1 °C over 1947-2001, the retreat is not surprising.