A SYNOPSIS OF GEOLOGIC RESEARCH ON MOUNT DESERT ISLAND AND ACADIA NATIONAL PARK, MAINE, 1920 TO 2010

Coastal Maine’s Mount Desert Island (MDI) and Acadia National Park have been a popular destination for both tourists and geologic researchers over the last century. Since 1920 more than 100 geologic research publications have focused on MDI, about 25 regional geologic studies have included MDI, and there have been 5 geologic guides for visitors to MDI. There have been only 10 or so primary geologic researchers working on MDI. Those working on the bedrock geology have been: Raisz, 1926 - 1929; Chadwick, 1937 – 1953; Chapman with graduate students Gilman and Metzger; 1953 – 1988; Wiebe and associates, 1991 - 2000; and Seaman and associates 1990 – present. The research done by these geologists exemplifies the evolution of thinking on the topic of bimodal gabbro-granite generation and intrusion over the last century. Raisz, Chadwick, and Chapman envisioned that the magma intrusions never reached the surface and that the gabbro intrusions were followed by the granite intrusions. Wiebe and Seaman envisioned alternating intrusions of gabbro and granite magma that reached the surface, formed a caldera, and produced a thick volcanic sequence preserved on the Cranberry Islands just south of MDI.

The primary researchers on the glaciation of MDI, maximum ice thickness on MDI, and the maximum sea height on MDI from glacial isostasy have been Raisz, 1926 - 1929; Chadwick, 1937 - 1953, Borns, 1974 - 1975, Lowell, 1978 - 1999. During the Raisz and Chadwick period the maximum height of the sea on MDI was still being actively debated with a wide range of inundation elevations suggested. With additional regional information the debate was put to rest in the Borns and Lowell period, though Lowell still thought higher levels were possible. Likewise, the debate over whether or not the mountain peaks on MDI were covered by ice was resolved by information from outside of MDI in the Borns and Lowell period. The MDI sea level height argument, started in the 19^th century, was a classic example of landforms assumed to have a single origin but that in reality had multiple origins.