Monday, December 19, 2011

LIP of the Month

I have been getting my share of LIP over the past number of days LIP stands for Large Igneous Provinces. The Large Igneous Provinces Commission part of the International Association of Volcanology and Chemistry of the Earth's Interior puts out a monthly paper by members on LIP.

From Barry and others (2010)

Washington State has one of the best studied LIPs - the Columbia River Basalts. The Columbia River Basalt Group (CRBG) have been a great LIP study site for a variety of reasons: 1) the CRBG are relatively young - older LIPs have been more eroded and tectonically disrupted, 2) the CRBG flows are relatively horizontal with only modest folds so that many individual flows can readily be traced, 3) access to the CRBG by geologists is relatively easy - lots or roads, not too cold not too hot, much of the CRBG is desert (although the CRBG does extend to very wet southwest Washington/northwest Oregon) and 4) lots of funding as the a portion of the CRBG was considered as a nuclear waste repository at one time.

Another noteworthy aspect of the CRBG is that it juxtaposes some other LIPs. A younger LIP is located across southern Idaho. In addition, the CRBG abuts the Crescent Formation basalts in western Washington and the Crescent basalts are very large in volume and fit the category of many LIPs in that the Crescent has been tectonically disrupted so it is not so easy to recognize as a LIP.

Given the amount of LIP we have here in Washington and the Pacific Northwest (I couldn't help myself) there are plenty of opportunities to see LIPs. Dave Tucker just posted a field trip to the Crescent LIP and a remarkable pillow basalt section

1 comment:

Anonymous said...

Hi, Dan,

I enjoy your blogs and especially appreciate the opportunity to learn new terms like "unconformities"and "residuum soil". Thanks for taking time to teach us all.

Shannon Parsons