Collecting Sand

Sand Reveals Geologic and Biologic Nature 



Sand Beach, Maine. photo ©2009, Rooptort.com

 

Sand fascinates me. I started collecting sand in 2001, during a camping trip to Mount Desert Island, Maine and a ranger-led hike along Great Head Trail and across Sand Beach. Stopping on a granite outcropping that presented a magnificent view of the Beehive and the beach, the ranger had us look at and touch the rock we were standing on. He passed out magnifying glasses so we could get a good look. I'm thinking, I've seen granite before but I'll play along. So I crouched down to look closely and notice. I don't recall how long each of my four children spent looking at the rock but I do know that they looked too.

The New Hampshire and Maine are known for their pink granite, an igneous rock formed of quartz and two types of feldspar, black and pink. The three minerals are roughly equal in proportion, and there are bits of mica sprinkled in along with a third type of feldspar, a white feldspar. After naming these minerals the ranger proceded to tell the group how this coast of Maine rock had once been connected to the coast of Spain, back a few hundred million years ago. Here is how one amature geologist describes it:

"Prior to 600 million years ago the World’s landmasses had been forming and reforming into groups until on almost opposite sides of the globe two super continents, one called Gondwana and the other Laurasia, had come into being. Slowly they drifted together and at about 600 million years ago they met and formed the giant extra-super continent, Pangea.


Pangea looked like a letter C, or a very distorted 8. A bit like a knobbly Pac man figure facing right, it’s mouth agape. But think of the 8, bent into a C shape. Where the two halves of the 8 meet, or perhaps where Pac man’s tonsils could be, were a few independent landmasses which had been crushed together and bridged the gap between the two continents. They are known as the Avalonian, the Amorican, and the Iberian plates."  Spain Rocks, by Richard Morley



Avalonia Rocks



It was the Avalonia rocks that connected what is now Maine and Spain. Geologists give a time range of between 400 and 600 million years ago for the collision of Gondwana and Laurasia. My attempts to verify that Maine and Spain are of the same parent rock concluded that parts of New England, including coastal Maine, did share parent rock with parts of Europe, including France and Spain.

 So back to our Maine hike, the group then continued walking the trail and ended up on the beach. Here the ranger had us looking at the sand with the magnifying glasses. In the sand I could see the parts of granite, broken into their respective minerals. But there were also green sea urchin spines and very small pieces of seashells. This little "aha" moment burst into my brain where I realized that sand on the beach can tell you the story of both its parent bedrock and the life that has lived there. This is way cool, I thought.

Now when I look at sand I look for evidence of the creatures that live(d) there. Pink Bahamaian sand, pink seashells.

Colorful and interesting
grains of sand

Recently I found a website that gave me better ammunition for those times when I got overly excited about sand in front of "muggles". Gary Greenberg took photographs of sand at a magnification of 250x. His work is gorgeous, combining art and science into amazing photograph-portraits. No one who notices these photographs could doubt my collection again. :)


A Couple References:

• Geochronology and geochemistry of the Pola de Allande granitoids (northern Spain): their bearing on the Cadomian-Avalonian evolution of northwest Iberia. Javier Fernández-Suárez, Gabriel Gutiérrez-Alonso, George A Jenner, Simon E Jackson. Canadian Journal of Earth Sciences, 1998, 35:1439-1453, 10.1139/e98-074
• CAMBRIAN-NEOGENE PLATE TECTONIC MAPS. Jan Golonka, Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063. http://www.dinodata.org/Golonka/phan.pdf
• The Natural History of Novia Scotia, volume 1: Topics and Habitats. Nova Scotia Museum of Natural History. http://museum.gov.ns.ca/mnh/nature/nhns/t2/t2-2.pdf: The Avalon and Meguma Zones.

Postscript:

Displays of sand can be found in the following places:

• International Society of Sand Collectors. (Even I was surprised by the existence of this group, and anyone can join.)
• Nima Sand Museum, Japan.
• Dig It: Secrets of the Soil. Exhibit at Smithsonian Institute. (OK, this is soil but sand is part of soil.)