Disappearing Wequobsque Cliffs demand caution from beach walkers
The marvelous cover photo in the Nov. 30 Times, titled "Lucy Vincent facelift," showing those colorful cliffs east of the entrance to the beach prompted me immediately to write a response. But I held back on submitting it, because a friend thought it was alarmist and preachy. But the events of the last week compel me to mount the podium.
Sometime in the past week or so the massive, fragmented portion of the bluff, shown so clearly in the photo, and weighing many tons, came crashing down on the beach in a matter of seconds. Clearly, if the couple in the photo had been there at that moment they would have been killed. As would have any of the rest of us who have stood in this very spot in awe of these stunning remnants of the Ice Age.
Yesterday, when I learned that the cliff had fallen, a friend of mine and I went to take a look. There on the beach beneath the bluff lay massive chunks of the fallen giant. This is a conglomerate, formed in the sea from pebbles cemented together by an iron oxide called siderite, in the Miocene Period, millions of years before the Vineyard, as we know it, existed. It is an example of sedimentary rock in the process of being formed. But the sea has other plans. Like the rest of the Wequobsque Cliffs, this too is being returned to the sea from whence it came, one pebble at a time.
This portion of the Vineyard is a close second to the Gay Head Cliffs as a place of awe and wonder to both casual observer and geologist. The Vineyard was formed by four glacial episodes during the past million years, yet it contains fossils from the Miocene Period, 11 to16 million years ago, and the Cretaceous Period, 60 to100 million years ago. Not as old as the Grand Canyon, but old enough. Please honor the wishes of the Wampanoag Tribe and the towns of Chilmark and Aquinnah, and take only photos and memories from these priceless resources.
We then faced about and walked the length of the beach at dead low tide, noting the enormous changes to the beach and cliffs since our last visit only a few days before. For example, the most recent storm surge had lowered the entire beach about four feet. In January, a storm thousands of miles from the Vineyard sent swells breaking as 12-foot combers on the beach, removing the sand beach and exposing a clay base for several hundred feet. In a matter of days the clay was once again covered by sand. These shifting sands south shore beaches. Indeed, the existence of the sandy south shore beach, from Chilmark Pond to Wasque, depends on the sand spread eastward from the Wequobsque Cliffs.
We passed at a safe distance from nearly vertical faces of compact yellow and white sand cliffs, noting the changes since our last trip. The thin black layers of lignite present a few weeks ago were gone, claimed by the sea. In 40 years of cliff-gawking, I had never seen lignite in any but the gray Cretaceous layers. Now it was gone. Lignite is an early stage in the formation of coal.
We came next to the spot where those massive concrete structures have been lowered down from the top of the high bluffs, as the clays and sands slump on their journey to the sea. Ugly as these unnatural monsters are, they are good gauges for measuring the recession of the bluffs, while gradually succumbing to the relentless attack of the breakers, especially storm waves. The first of the two structures to reach the beach has already broken into many pieces. Here the bluffs are water-saturated clays, in constant motion, and instead of receding from the concrete structures, the clay is oozing towards the structures, which temporarily shield the clays from the power of the sea.
Finally, we reached a spot where a bizarre morainal mixture of white sands and gray clays had recently slumped onto the beach. The formation was only eight or 10 feet high, and undercut to form a shallow cave. We could have approached this interesting formation to examine it more closely, but we stood some 20 feet away watching a handful of material fall here and another there, from the roof of the indentation. Then a bushel fell. Then a ton or more followed a split second later. The formation was gone. We looked at each other, uttered a few expletives and said almost in unison: "Whoa! Glad we didn't approach closer to that one!" We both realized we could have been buried alive in an instant.
By now you can probably guess what I'm driving at. Lucy Vincent Beach and the Wequobsque or Windy Gates cliffs are spiritual places, places of serene beauty, away from the places and the sounds of man, places where we find re-creation. They are places of enormous interest to those who have a penchant for knowing more about the secrets of nature and the geological wonders about us. But, these are also places where the beautiful power of nature is fully in play and fully in charge. For the preservation of your precious lives, I urge you and those you love to be mindful of the constant potential for instantaneous sheering and slumping of the cliffs.
The Vineyard Conservation Society is sponsoring a special winter walk at Lucy Vincent on April 14.This will be in concert with a thousand other events to be held throughout the country in support of Step It Up, a movement highlighting the need for human changes in light of global climate change. We will be looking at the effects of the sea upon the cliffs and talking about what to expect in the future. Geologists Bill Wilcox, Chuck Ratte, and Craig Saunders will join me in sharing what we know of the Vineyard's complex and fascinating glacial history, as revealed in the cliffs. Please join us.
Bob Woodruff, a coastal ecologist and a former executive director of Vineyard Conservation Society, periodically leads excursions such as the one planned for April 14.