Granite

If you've only had local experiences, 'rock' and 'granite' are synonymous. It's hard to distinguish something utterly common when you can't imagine a world without it.

Granite boulder

For the layman the question about granite is, "Compared to what?" It's elemental around here, like air and water. To gain perspective you can do what people with big questions have traditionally done, turn to science and religion. Or you can visit other places, then come back and walk around Halibut Point.

Granite landscape, Halibut Point

In these parts granite refers to bedrock, to masonry, to an historic industry. It connotes rugged durability. Quarrying it, shaping it and shipping it all present challenges,  but once it's in place granite outlasts most other materials.


Folly Cove pier,
the shipment point for Halibut Point granite a century ago

Stone in general is hard and heavy, the moreso if like granite it forms deep within the earth where molten minerals, cooling slowly over eons as they move upward into the crust, crystallize into a dense grainy matrix. Granite gets its name from the Italian word for grainy. Its origin is igneous, 'from fire.' 

Chemically similar blends of magma that cool and petrify more quickly will not develop the combination of strength and grain that characterizes  granite. Compare it to the finer-textured rock below, which may have been brought from afar by a glacier, or eroded from a relatively quick-cooled intrusion within the bedrock.

An exotic boulder on the Halibut Point shoreline

Wikipedia affords us amateurs considerable information about mineralogy, which you can follow to the depth of your choice. I learned that silicates comprise ninety percent of the earth's crust and structure all the important components of granite: quartz, feldspar, mica, and amphibole. These particulates are visible in the enlarged photo below, forming the matrix and grains of the granite background stones.

Boulder details

Silicates are compounds of silicon and oxygen. We are very familiar with oxygen in the form O₂ in the air we breathe, and as an essential element of organic life with carbon and hydrogen. Quartz, the hardest component of granite, consists entirely of silicon-oxygen molecules SiO₄. Oxygen atoms win the versatility sweepstakes.

Feldspar silicates make up much of the mass of granite as well as shaping its particular 'behavior.' It's the lighter-colored substance in the photo. It may take on pink, gray or brown tints according to its chemical individuality and lend specific characteristics to the stone.

All granites are felsic, relatively rich in elements that form feldspar and quartz: silicon, oxygen, aluminum, sodium, and potassium. Granites can be contrasted with mafic rocks, which are relatively richer in magnesium and iron (ferric). Incorporating denser metals that predominate in the earth's core, mafic rocks such as basalt are heavier than granite. Felsic rocks tend to 'float' above them in the earth's crust, forming the continents.

Quarry walls

All manner of other factors go into shaping granite as we encounter it. A significant presence  of iron stained the stone pictured above. Water seeping through fissures dissolved and oxidized the iron, concentrating it around joint surfaces. Local stoneworkers call it 'sap-faced granite.' 

Granite begins as a monolithic formation far below the earth surface. Cracks and seams develop as conditions change. Incomprehensible pressures increase during tectonic collisions. Conversely pressures decrease when the stone is relieved of miles-thick overburden through millions of years of erosion. The accompanying expansions, contractions, and shifts are expressed in the pattern of joints. According to their placement the joints make the stone more or less desirable for quarrying. 

All granite is not equal. The cakey-looking Chelmsford granite utilized these days for curbstones on our Cape Ann streets - cheaper to saw and split - disintegrates at the first rap of a snowplow.

 

Mastering the challenges and employing the qualities of Cape Ann granite imparts a satisfaction to tradesmen and sculptors, as well as integrating their artisanship to the native terrain with a cohesion for all to enjoy. Nature's vernacular engenders our own.

Gems and Geology

Gems catch everyone's eye as things of beauty and usefulness. Geology reveals part of their origin story in the minerals we stand on.

At Halibut Point geology means granite. Barbara Erkkila, our doyenne of granite, wrote about the industry (Hammers on Stone, 1980) and also fashioned granite into jewelry. Broadly speaking Barbara made granite into a gemstone. People who knew her personally think of her as a gem.

Red granite buckle by Barbara Erkkila

Halibut Point is Everyman's encounter with geology. The ocean, glaciers and quarrying have presented the bones of the continent in plain sight. We can't help wondering at least a little about it all.

Geologists wonder full time. At Halibut Point we've been fortunate to have  geologist John Ratti as Park Interpreter since 2005. John tries to make it comprehensible for the rest of us. As a subject area it is full of intricacies, mysteries, hunches and specialized vocabulary, just like all other branches of knowledge. It's not an exact science but it contributes to progress and the satisfaction of curiosity.

John Ratti pointing out glacial scouring and 'chatter marks'

Here's what it's like to have the geology bug: John says that every time he drives by roadwork or a blasting site, he wants to go back for a look. "If you're a geologist, that's like heaven." A free pass into the earth's crust. 

Andrews Point pegmatite seam

Adjacent to Halibut Point lies a celebrity feature in Massachusetts geology, the Andrews Point pegmatite that includes large 'blue' quartz crystals. These look like low-grade amethyst and may once have included gem-quality stones plucked away by earlier adventurers. By commercial standards what we see now lacks preciousness, falling short in terms of color, translucence and rarity. 

'Blue' quartz, close up

Interesting things happen in pegmatites that draw the attention of geologists all around the globe. Pegmatites seem to originate as a creative chemical soup at the interface of magma masses deep within the planet, perhaps in the presence of super-heated super-pressurized air and water trapped alongside. If these conditions remain for a very long time exotic crystals can form and grow.

 

John Ratti is always on the lookout for pegmatites. He split open a promising-looking boulder with a feldspar seam that he noticed on Halibut Point. Inside were two minerals that had caught his attention years before at the Harvard Mineralogical Museum, because of their Cape Ann associations. He has put them on display at the Visitors' Center.

Danalite and annite within feldspar, Halibut Point

Back in the 1860s Yale Professor James Dwight Dana described the very first examples of these minerals right here in Rockport. You can imagine that our quarrying industry provided an attractive hunting ground.  Danalite is named for him, the reddish crystal Fe²⁺₄Be₃(SiO₄)₃S above. Within the once-molten pegmatite traces of beryllium, silicon, and sulphur found just the right chemistry with iron and oxygen.

The black mineral in the photograph is annite, a member of the mica group. It contains large amounts of potassium. According to its Wikipedia article annite is of special interest to geologists in potassium-argon dating processes that determine the age of articles older than 1000 years. It also preserves an ancient record of the direction and intensity of the local magnetic field, which give geologists clues to rock origins that may have been thousands of miles away.

Park Interpreter John Ratti

Halibut Point is a walkabout storybook preserved by the Massachusetts Department of Conservation and Recreation. John Ratti enjoys taking us through the pages, even when he has to disappoint kids who came to catch frogs in the tide pools. He has the storyteller's gift of knowledge, excitement, and weaving together human history with the environment. John is the gem within the gem.

Witch-hazel

When we built our house on a half-acre wooded lot in Lanesville, Kay and I tried to site it with regard to the understory of witch-hazel shrubs among the trees. They have flourished these thirty years with four-season appeal.


The native witch-hazel, hamamelis virginiana

The dozen or so witch-hazels around us conjure fall color incandescently in the landscape. The one pictured above sports gold margins around its leaves. Shafts of sunlight tease its patterns in and out of prominence.

October flowers

Witch-hazel flowers, modest and balletic, await discovery within the foliage. Their shyness may be the reason that the shrub remains almost unknown in the nursery and landscape trades. You have to seek the acquaintance. You will smile at the garlands of little Sarah Bernhardts throwing petals over-shoulder in all directions, out-waiting every other woodland flower to have the blooming stage to themselves.

Winter filigree

Arching stems and zigzag branchlets make the shrub picturesque even out-of-leaf. A glazing snow emphasizes its tracery. The pendulous weight of winter broadens its umbrella shape gracefully.

Spring leaves budding

When the weather warms again witch-hazel leaves break dormancy in emergent pairs among the residues of last year's fruit and flowers.

Summer production

By midsummer, when this year's leaves and fruit have fully expanded, new flower buds are developing. At this point squirrels become steady visitors. They never find all the nuts.

Fall again.

  By mid-October horizontal planes of witch-hazel are lighting up glades within the trees, especially in woodland margins alongside our lawn and driveway. Thanksgiving is in the air.

Witch-hazel has not yet returned to Halibut Point within the State Park boundaries,  following epochs of agricultural and industrial clearing. But it exists on at least one adjacent property. Squirrels may hasten the restoration as woods recover their realm.

Red October

All summer long Nature has been preparing for the bonfire of October, showing red ever so sparingly as though not to steal fire from autumn's flames. Of course the sky above has been coloring itself by different rules.

Staghorn sumac, rhus hirta

At Halibut Point sumac trees signal the new season. They flaunt the ascent of red, its complexities in relation to yellow, and the innumerable varieties of orange born to their liaison. While most of the landscape retains its verdancy the sumacs seem impatient for celebrity. Obligingly we admire them.

Attaining red

Every so often you may be satisfied that true red stands before you. It depends on your angle of view, the time of day, and your visual vocabulary. Good friends may not agree with your conclusion.


European barberry, berberis vulgaris

For instance my artistic wife and I considered together a reasonable color designation for these barberries. Nearby orange leaves helped nudge our consensus slightly to the yellow side of center, to vermilion.

Black huckleberry,  gaylusaccia baccata

Adding yet a bit more yellow takes us to scarlet. Highlights on huckleberry leaves emblazon scarlet across the moors on a misty day. Admittedly the effect is complicated by deeper tones within the foliage.

Cardinal

For assurance on true scarlet we look to the bird named for the cassock color of Catholic prelates.

Sour-gum tree, nyssa sylvatica (center)

I contemplated this full-spectrum scene by the quarry to see if the shadows in the sour-gum contained purple, from an infusion of blue, or merely a deep intensification of its red. Painters might achieve the maroon effect by adding touches of both blue and yellow into their red.

Sassafras, sassafras albidum

Within these sassafras leaves red transmutes to mahogany rather than the tree's more typical yellow-orange fall coloration, probably because if its dry location. What an artist attains with pigments the leaf embodies in the glory of its demise.

Poison ivy, rhus radicans

The final adornment of poison ivy incorporates rose, crimson, and claret among its reds, which seem reminiscent of both fruit juices and of wines.

Virginia rose, rosa virginiana

All along the shoreline roses mature to berries in the mode of cerise, the French cherry.

 
We're called to notice an autumn sky where red takes full liberty with blue and yellow, playing into sepia and violet above carmine and coral. The sun is setting not only on the foliage pageant but on the hospitality of shirt-sleeve rambles.

On Our Feet

 

White-breasted nuthatch

If you're going to understand how I'm able to walk up and down tree trunks, I want to give you my perspective on growing up a bird.

Your scientifically-minded community has a pretty good grasp on how things happen. They've organized me and most of my friends into an ornithological order called Passeriformes, which is based on the way we perch.

Take a good look at brother titmouse: three toes forward and one toe backward, all joined to our legs at the same point. That defines passerine. Our grip closes automatically when we land on a branch, and stays that way even while we're sleeping.

Tufted titmouse

But it's not just about sitting. We can cling to almost any surface, like this phoebe on the quarry wall.

Phoebe on quarry wall

It's only partly about geometry. Our toes extend into sharp claws. We need them at precarious moments.


Downy woodpecker at upside-down business

Some of my arboreal friends spend so much time in awkward positions that they've re-arranged their toes to make life easier.

Not a passerine

 In doing so the woodpeckers have earned their own order Piciformes among the science-minded: two toes forward, two rearward. That's clever on everybody's part.

Great blue heron

I was noticing the other day that the tall fellow by the quarry pond has three toes forward like me, but he's a wader not a percher. Overall his feet are nothing like mine. I could never walk on oozy ground without sinking. The scientists knew their stuff putting him in a separate order, the Ciconiiformes, which in their Latin language means 'stork-like.'

Double-crested cormorant

There's a place by the quarry where seabirds sometimes stand out of the water, which gives me a chance to satisfy my curiosity about their propeller feet. Absolutely not handy for perching, but powerful for swimming. When I checked into their standing with ornithologists I found a complication, that the cormorants may be reassigned from the order Pelecaniformes ('pelican-like', four toes webbed together) to Suliformes ('gannet-like'), which I like, because gannets visit Halibut Point and pelicans don't.

Turkey dust bath

Speaking of big feet, I was watching some turkeys at a dust bath the other day and was very impressed with their ability to scratch away the turf.

Tom turkey

Spending all day on the ground, they have three specialized toes for walking, foraging, and running like the blazes when trouble comes along. Their fourth toe, the spur with the claw, makes Old Tom fierce in a heated moment. He's in an order with fighting cocks, Galliformes, 'chicken-like' but lordly.

Circling hawk

The feet I shudder to mention belong to raptors, which refers in Latin to 'seizing by force.' Their sinister talons can snatch warm bodies like mine from the treetops. They clench with a relentless, opposable hind claw. The ornithologists have decided to be fair-minded to birds of prey, according them the order Falconiformes.

A heroic crow chasing the hawk away

When hawks come around my robust passerine kin come out in force for the safety of the neighborhood. They don't rely on their feet for this feat, but on agility and esprit. 

 

I have to be alert all the time to stay out of trouble. Really, I don't bother anybody except the bugs in the bark.

I'll show you the trick. My toes help me scramble around the branches. They're state-of-the-art in perching design. Over, under, up and down, it's all the same to us nuthatches.