Our Landscapes: How We See Them, How We Save Them

Editor’s Note: The variety of landscapes that comes from the variety in our geology — from sandplain grasslands to glacial moraines — has drawn or inspired artists for centuries (see Hermine Hull’s essay, Why Paint a Landscape?).

The Vineyard’s community of artists, wrote Sam Moore in a story in Arts and Ideas Magazine five years ago, are a key ingredient in conservation. … “They have a dual role: Many of them are affected by the land around them, and they help set the terms by which other people appreciate it.

“Island artists help us look at the landscape still more closely — to understand what might be at stake, and to imagine what the future holds. Painters, photographers and sculptors represent a middle range on the spectrum between ecologists and everyone else. Artists share this acute sense of detail, but weave it into an aesthetic process that might influence less empirical minds.” 

To find out how we ended up with the landscape, we turned to Island engineer and geologist Doug Cooper. We sent him images of paintings and photographs collected by Jennifer Pillsworth and Chris Morse at the Granary, Field, and North Water Galleries, and by Art Director Tara Kenny, and we asked him to describe for us what, beyond art, we were looking at, how the geology created the landscapes that artists are perpetually inspired by, and the rest of us are moved to preserve. 

– Jamie Kageleiry

Gay Head, at the Aquinnah Cliffs, has the oldest exposed geologic materials observed on Martha’s Vineyard, composed of ancient marine (sea bed) deposits that date back well before the glacial periods of more recent geologic time. The variable sands, silts and clays exhibit a wide range of colors that are visible from great distances under the right meteorological and sun angle conditions. As such, mariners were able to identify their location when sighting this brightly colored headland (hence the name “Gay Head” was derived).  The intensity of colors of the cliffs changes over time as erosive forces expose brighter or duskier layers. The cliffs have always been a favorite attraction for artists and sightseers. The headland was also the most logical site for early lighthouse construction. Cliff collapse and erosion can be impressive and has resulted in several relocations of the lighthouse over the years. 

The beaches that surround Martha’s Vineyard are as variable as the landscape from which they have evolved. The exposure to the ocean currents and wave action on the earth materials determines the character of the beach. Erosion rates along the South Shore can be on the order of seven feet per year. Less dynamic settings that are protected from the brunt of coastal storms may retreat less. There are also beaches where transported sediments are deposited resulting in “accretion” or beach building where the shoreline is extending outward rather than vanishing. There are areas where the shoreline retreat has exceeded 1500 feet since early colonists arrived. Periodic storm events often result in newspaper headlines of the destruction of a particular beach and the need to implement measures to “save” the shoreline. These measures will always prove futile in the long term.

Salt marshes develop along portions of our shoreline where the erosive energy of wind, waves, tides and currents are more benign. Accumulated sediments and organic materials allow the growth of salt-tolerant grasses such as spartina patens and spartina alterniflora to establish root systems. These grasses tend to accumulate even more organic material and fine sediments to form a resilient mat that serves to protect the shoreline and adjacent coastal banks from erosion. The marsh also supports numerous organisms that contribute to the food chain and sustain fin fish, nematodes, insects, shellfish, and birdlife, while contributing to water quality improvement.

Breaches of salt ponds, embayments and coastal estuaries can occur by natural, storm-driven events or by planned “openings” as part of a man-made management strategy. Whatever the mechanism, these cuts, breaches, or openings can profoundly influence the salinity, water quality, currents, sediment deposition and aquatic life within the pond or embayment. Historically, cuts or breaches were accomplished to create conditions that would stimulate fish or shellfish production.  More recently, sluicing of nutrient-rich waters out to sea and introducing a flush of cleaner salt water is viewed as a means to reduce algae blooms in the ponds.

The North Shore of the Vineyard is the polar opposite of the South Shore. This upland is dominated by the moraine deposit that identified the terminus of the last glacial advance. 

Approximately 25,000 years ago, the rate of advance of the Wisconsin ice sheet slowed, stalled and began its retreat northward. The accumulated sediments within and under the ice were dropped to form this side of the Island. Raging torrents of meltwater then carried some of the glacier’s load southward to form the outwash plain along the Island’s South Shore. The North Shore in the vicinity of Great Rock Bight shows the steep cliffs composed of unsorted glacial debris being slowly eroded. Boulders and stones are exposed and sit on the surface as “erratics” or fall to the shoreline, creating very interesting beach and water features. The North Shore moraine is also a source of clay deposits that once supported a brick-making operation. The chimney of the brick kiln still exists, and you can see it from the Menemsha Hills Reservation. The upland forests also provided wood to fire the kiln and were extensively cut for this purpose.

Meadow grasses are a resilient vegetative cover in a harsh maritime environment. These meadows can be a beautiful interlude in the more “scruffy” coastal heath and brush landscape. Human recreation, birdlife and fauna also benefit from grasslands whether they are managed by mowing or, occasionally, by controlled burns.

The multi-colored silts and clays of the cliffs around Wequobsque and Aquinnah erode to form sections of beach that depart from the white “sugar” sand of the barrier beaches or the brown beaches at the base of eroding cliffs of the north shore morainal uplands.

The coastal uplands in the area of Stonewall Beach and the Allen Farm in Chilmark provide spectacular vistas that have drawn tourists and artists for centuries. These uplands are part of the glacial moraine deposits that form the “spine” of the Island. Moraine deposits are the result of the dumping of the unsorted glacial load of boulders, rocks, cobbles, sand, silt and clay when the ice advance stagnated. The resultant rolling, rocky landscape was difficult for planting crops, but early occupants found that grazing livestock, particularly sheep, could be profitable. As erosive forces proceed, the heaviest constituents of the morainal deposits (rocks) remain in place while sands, silts and clays may be washed out to sea, leaving a very stony beach and plenty of boulders for stone wall construction.

Coastal ponds, particularly the Great Ponds located along the Island’s South Shore, are unique and dynamic features on the Vineyard landscape. They formed in low-lying sloughs and channels in the outwash plain to the Wisconscian sheet. These ponds range in salinity from freshwater to brackish and occasionally saline when the ponds are breached by natural storm-driven or man-made openings. This range of salinity creates conditions that sustain an abundance of plant, animal, and, particularly, avian life. The ponds are separated from the powerful waves and currents of the Atlantic Ocean by barrier beaches and dunes that act as soft shock absorbers to the ravages of inexorable erosion and storm events. Consequently, the ponds are ever-changing landscape features.

The great sand plains of Martha’s Vineyard are the result of outwash of sediments from the terminal moraine of the last glacial advance. Sediments from lodge rocks and cobbles to gravel, sand, silt and clay were sluiced off the massive dump of moraine by torrents of meltwater as the ice sheet stagnated and then began its northward retreat. These sediments were sorted by virtue of grain size and water velocity and later re-worked and capped by fine materials deposited by strong “katabatic” winds in the immediate post glacial period. These dynamic forces resulted in an expansive nearly level plain that is unique to New England. Some of the island’s best “tillable soils” are found on this landscape feature. 

The relative tranquility of the salt pond environment allows the development of significant, stable marsh grass habitats that serve to physically protect the shoreline, remove nutrients that might otherwise harm the pond and provide nesting and food source for numerous forms of wildlife.