Wednesday, April 26, 2006

Beautiful Day On the Cove

The light is really changing here on the cove. Though we could use a little warmer weather (it is 48F at noon today), the days are longer and the grass is greening up. The magnolias and forsythia have bloomed, most of the trees are budding and the days are getting warm enough to work in the garden/yard.

Thursday, April 06, 2006

More on Petrology

The petrology field trip got me thinking...just what was so interesting around Lanes Cove. I posted a question on a local forum and someone posted a USGS (US Geological Survey) bedrock map of Cape Ann. Just south of Lanes Cove (where the field trippers were looking) were a couple of diamonds. I asked what they represented and the reponse was "Hornblende diorite porphyry inclusions - Predominantly Salem Gabbro-diorite porphyry characterized by large (up to 10 cm (4 in.) long) white-weathering, red-purple labradorite phenocrysts".

Now, I wouldn't know a labradorite phenocryst if it bit me on the a**. This morning was the first time I could get out there during the daylight, so I took a few pictures and e-mailed one off to Prof. John Brady, Geology Dept. Chair of Smith College in Northampton, Mass. He was kind enough to inform me that my photo was a "pegmatite dike" with bluish quartz crystals.

Hornblende diorite porphyry inclusions

Prof. Brady was also nice enough to send me a picture of the diorite porphyry inclusions that were taken on Sunday.

pegmatite dike with bluish quartz crystals

I guess I'll have to get out there and see if I can find those phenocrysts.

Sunday, April 02, 2006

Petrology on Lanes Cove

I noticed three vans wizz by the house this afternoon, two from Smith College and one from Amherst College Geology department, filled with what I assumed were college students. I ran across the Smith College website a while ago with pictures from previous field trips. Though I didn't talk to them, I believe the course to taught by Prof. John Brady. Oh, and Petrology? It is the study of rocks.

So the students spent quite a while examining the rocks on the shore just south of the cove. My guess (from the pictures of previous trips), they headed for Woodman's in Essex for dinner before heading home. directory