Glacial Erratic, unremarked

This maple tree is one of the first plants to flower in spring.

Pam and I ambled around the Arboretum for our Easter 2023 outing.

Click Me for “Finger Lakes Memories” my online gallery.

All photography using the IPhone 14 ProMax triple camera, raw format, edited on the phone.

We find boulders of crystalline rock, commonly derived from Adirondack sources, left behind on the surface of ablation moraine, in the Finger Lakes Region.

Cornell finds some and move them, maybe the case for this unremarked erratic found along the Allen Trail of FR Newman Arboretum.

Another enormous erratic, brought in from the Sixmile Creek valley, was carved into a seat as a memorial to Professor R.S. Tarr who deciphered much of the glacial history of the Finger Lakes Region. Find it at the southwest corner of McCraw Hall on the Cornell University Campus.

History (from wikipedia)

During the 18th century, erratics were deemed a major geological paradox. Geologists identify erratics by studying the rocks surrounding the position of the erratic and the rock of the erratic itself. Erratics were once considered evidence of a biblical flood, but in the 19th century scientists gradually came to accept that erratics pointed to an ice age in Earth’s past. Among others, the Swiss politician, jurist, theologian Bernhard Friedrich Kuhn [de] saw glaciers as a possible solution as early as 1788. However, the idea of ice ages and glaciation as a geological force took a while to be accepted. Ignaz Venetz (1788–1859), a Swiss engineer, naturalist and glaciologist was one of the first scientists to recognize glaciers as a major force in shaping the earth.

In the 19th century, many scientists came to favor erratics as evidence for the end of the Last Glacial Maximum (ice age) 10,000 years ago, rather than a flood. Geologists have suggested that landslides or rockfalls initially dropped the rocks on top of glacial ice. The glaciers continued to move, carrying the rocks with them. When the ice melted, the erratics were left in their present locations.

Charles Lyell’s Principles of Geology (v. 1, 1830) provided an early description of the erratic which is consistent with the modern understanding. Louis Agassiz was the first to scientifically propose that the Earth had been subject to a past ice age. In the same year, he was elected a foreign member of the Royal Swedish Academy of Sciences. Prior to this proposal, Goethe, de Saussure, Venetz, Jean de Charpentier, Karl Friedrich Schimper and others had made the glaciers of the Alps the subjects of special study, and Goethe,[15] Charpentier as well as Schimper had even arrived at the conclusion that the erratic blocks of alpine rocks scattered over the slopes and summits of the Jura Mountains had been moved there by glaciers.

Charles Darwin published extensively on geologic phenomena including the distribution of erratic boulders. In his accounts written during the voyage of HMS Beagle, Darwin observed several large erratic boulders of notable size south of the Strait of Magellan, Tierra del Fuego and attributed them to ice rafting from Antarctica. Recent research suggests that they are more likely the result of glacial ice flows carrying the boulders to their current locations.

The Finger Lakes Region: Its Origin and Nature,” O.D. von Engeln, Cornell University Press, 1961 page 106.
Wikipedia, “Glacial Erratics”
Copyright 2023 Michael Stephen Wills All Rights Reserved

2 thoughts on “Glacial Erratic, unremarked

  1. When I was living and teaching in northeastern Montana, the remnants of glacial activity were commonly found in an area where the last glacial age stopped. Many a farmer has had to pick rocks from a field, and the chore never seems to end.

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