Written in Stone - New England Geology

After Ed Myskowski piqued my interest in the geology of New England, I borrowed "Written in Stone" by Chet and Maureen Raymo from the Arlington Robbins Library. A great introduction to the geology of New England. Plate tectonics is central to the discussion. It has changed my whole conception of time, and how mountains, lakes, rivers and valleys formed.

I had heard about "Pangea" the super-continent, but hadn't heard about how the continents were arranged before they coalesced to form Pangea. As impressive as our mountains are now, this book describes how before Pangea a mountain range rivaling the Himalayans stood along what is now he East Coast of North America. At the time though, this land was located near the equator.

The continents have joined and separated, plant and animal species have come and gone, rocks have formed, compressed and changed, mountains have been thrust up and have eroded to plains. In geologically recent times, the land has been shaped and tilled by glaciers. In the last few moments of geologic time, a creature with an unusually large brain has walked the earth. The longevity of this species is to be determined, over the next few 100 millions of years.

For a great animation of the tectonic movements of the earth's land masses, leading to our current continents, see this Animation from UC Berkeley . Note that you can step through the sequence slowly with the left/right arrow keys. Watch Florida float into place at about 430-270 (million years ago) and India zoom up and slam into Asia starting about 120 million years ago.

Geology Hike at Middlesex Fells

"Because it helps you build up a relationship to the earth in a mysterious kind of way ..."

On Saturday morning December 5, ~30 people gathered at Bellevue Pond in the Middlesex Fells for a Geology Hike sponsored by the Friends of the Fells and led by Ed Myskowski of the Peabody Essex Museum. Ed is friendly and knowledgeable, happy to share his considerable insight into the geology of New England. Before setting out he covered the basics of plate tectonics and the effects of glaciers on the New England landscape. He even delved into recent theories proposing that periodic variation in the earth's tilt (varying between 21-24 degrees, with a period of 40,000 yrs) is responsible for the historical cycles of glaciation observed (~100,000 yr period), and discussed possible implications for climate change in the future. Ed is pictured below with a gabbro boulder that seems to have been conveniently placed alongside the pond for demonstration purposes. This type of rock is ~600 million years old, sometimes called "country rock", meaning, a component of the local bedrock. It formed at a time when the continents were still connected in a big land mass (called Pangea). New England was butted up into what is now north-western Africa.

Igneous rocks (from molten magma far below the surface) make up some of the more interesting formations in the Fells. While the varying compositions and formation mechanisms are complicated enough to be the lifetime work of many geologists, their beauty is easy to grasp. Ed told a great story about talking to a group of young school children about igneous rocks. It seemed to Ed their attention was drifting, so he asked "but why should we care about igneous rocks?". A reply came back: "because it helps you build up a relationship with the earth in a mysterious kind of way". I bet Ed felt great about his work with kids on THAT day.

The word "Fells" is an English word for "rocky windblown hills". Formations as shown below give character to the terrain, making for enjoyable hiking. The numerous paths are also favored by runners.

Our hike took us to Wright's Tower on the south-eastern tip of the West side of the Fells. Great views of the Boston Skyline, and the site of the ancient Boston Caldera. (That's another story, that Ed will talk about on February 9 2010, watch the Friends of Fells site for details).

I like the combination of the natural Lynn rhyolite rock feature and the man-made stairs and tower.

I can almost still see the swirling magma flows in this rock, and the glacial scratches.

And wow, does it confuse a compass - the white line painted on the rock in the photo below runs North/South. As you can see, the compass points almost due west!

One of the most clear examples of a dike, where magma has intruded into cracks in the bedrock. Some grass has grown where the two rock types meet, providing an even better marking of the division.

Click on any of the photos for more detail.

Winter Moths

The Winter Moth have definitely arrived in Arlington MA. These photos were taken the evening of November 25 2009. The male moths shown are attracted to light and to the wingless females. After mating, eggs are laid in tree bark crevices, under lichen and elsewhere. In the spring the eggs hatch and release tiny and destructive caterpillars (larvae). They eat tree leaves, dropping their droppings below, and swing down and sideways onto other trees by filaments. They are destructive to oaks, apple trees, roses, other perennials, and are the bane of blueberry growers in coastal areas, inflicting considerable economic damage. You may have seen swarms of these when driving at night or raking leaves.

For more information, see the excellent U Mass Extension Fact Sheet

by Robert Childs and Deborah Swanson.

Middlesex Fells - Thanksgiving 2009

Thanksgiving 2009, Arlington MA - a morning with fog so dense and white that trees just a block away faded into mist. Damp but fragrant air, temperatures in the mid 40's. A great day for a walk in the Middlesex Fells, a natural treasure just around the corner in Medford.

The light on this cloudy day illuminated mossy logs and lichen-covered rocks in a magical way. The photos show a "nurse log", supporting vibrant green moss, a pine seedling, and a small community of healthy fungi. A tiny wintergreen (pipsissewa) grows alongside - it will provide a welcome green all through the winter.

We traversed many small hills and ravines. A pervasive quiet, and sounds of birds left the din of civilization fading into the background. At one point we paused, hearing the sound of something dropping from trees. Might it be just water droplets? Looking skyward, we saw birds feeding on catkins in a tall birch tree. We were hearing the sounds of bits falling from these crumbling catkins as they hit the brown crinkly leaves covering the ground. I had never experienced this before. Nature will always surprise and delight.

You may click on the photos above for a larger image.

The Route: Start at the smaller Parking area just south of the Long Pond Parking area on South Border Road, on the west border of the Fells. Proceed south along the Skyline Trail, about 1/4 mile to where it joins the Reservoir trail. Take the Reservoir trial north for about a mile, to north of Nanepashemet Hill, where it crosses the Skyline trail. Take the Skyline trail left, turning south for the return trip. While the trails are very well marked with white and orange blazes (small squares on the trees and painted on rocks), having the excellent map and guide published by the Friends of the Fells is essential for not getting lost in the Fells (not that getting lost is all that bad).

Seasonal Scenes: Jan-Feb-March 2009

The winter of 2008-2009 brought us our share of snow and cold in Arlington MA, but many days were also sunny.  Getting out into nature was always restorative and much needed.  The video below shows typical nature scenes in Arlington and vicinity at this time of year.  Relax and enjoy the scenes and music.  Most importantly though, there is no substitute for getting out and experiencing nature first-hand.  The video shows several places in or very near to Arlington that are wonderful places to explore.

The Arlington Natural Connections Project would appreciate receiving contributions of photos that document nature in the current season.  Select photos may be displayed in on-line galleries, photo collage videos or other works created as activities of the Arlington Natural Connections Project.  The contributing photographer will be credited, unless anonymity is requested.  Please include: place, date, time (optional) the photo was taken, and the photographer to credit.  Submission of photos is taken as permission to use in these venues.  

Please submit digital photo files to: 

joe@naturalconnectionsarlinma.com

The mission of the Arlington Natural Connections Project is to promote a sense of connection to the natural world by combining an artistic and natural science approach.

Tracking Hike at Arlington Great Meadows

On Sunday February 1, temperatures soared into the balmy range near 40F. What a great day for a Tracking Hike in Arlington's Great Meadows. The event was organized by Don Miller and David White of the Friends of Arlington's Great Meadows . We split into two groups, one led by Lydia Rogers and one by Fran Ludwig. Although we didn't have the dusty covering of new snow that would make conditions optimal for spotting tracks, we did see some. We learned about the X pattern that all dogs make when they leave a track. We saw squirrel tracks, identifiable by the larger tracks in front (made by the back feet) with smaller tracks in back (from the front feet). I was embarrassed to realize that I didn't really know how squirrels ambulate around, despite having a bird feeder in my yard that is a major squirrel attraction every day. A nice picture of squirrel tracks and a drawing of how they move is here. As usual, you may click on photos to see them enlarged.

The snow was textured by cycles of warm/cold and the rocks, branches and other objects lying underneath.

The Friends of Arlington's Great Meadows group have made many improvements that enhance enjoyment and accessibility.

We saw these beautiful ball-shaped oak galls, and also another type more elongated and integrated into the branches of a bear oak. Although these make interesting additions to my "natural collections", I am always conservative about collecting these galls because they provide such visual interest and are part of a fascinating natural system.

Thanks Lydia, Fran, Don and David for organizing this!

Habitat, Mass Audubon Wildlife Sanctuary, Belmont MA

Took a walk on Saturday afternoon, January 24, 2008 around the Habitat Education Center and Wildlife Sanctuary, a Mass Audubon Society property, at 10 Juniper Road, Belmont MA. The temperature was in the 30s, with some wind. The wind was audible, whistling through the pine trees high overhead. Also heard rustling of some oak leaves that have hung on all winter, some lyrical birds, and the occasional tree branch clunking against another as it moved in the wind. The sky was visible through the bare treetops, more so than in summer when the canopy is dense with leaves. The birch grove shined brightly, vividly white. The dense trees shielded walkers from the wind. Especially in the sun, I was quite comfortable when walking around. As usual, you may click on photos to see them larger.

A great place to ward off the effects of nature deficit. Very close to Arlington. Plenty of parking, visitor center has rest rooms.