Glacial erratics from Norway on Schokland in the NetherlandsGlacial erratic boulder in Snowdonia (Eryri), Wales
A glacial erratic is a glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from the Latin word errare ("to wander"), are carried by glacial ice, often over distances of hundreds of kilometres. Erratics can range in size from pebbles to large boulders such as Big Rock (16,500 tonnes or 18,200 short tons) in Alberta.
Geologists identify erratics by studying the rocks surrounding the position of the erratic and the composition of the erratic itself. Erratics are significant because:
They can be transported by glaciers, and are thereby one of a series of indicators which mark the path of prehistoric glacier movement. Their lithographic origin can be traced to the parent bedrock, allowing for confirmation of the ice flow route.
They can be transported by ice rafting, which allows quantification of the extent of glacial flooding resulting from ice dam failures which release the waters stored in proglacial lakes such as Lake Missoula. Erratics released by ice rafts that were stranded and subsequently melted, dropping their load, allow characterization of the high-water marks for transient floods in areas like temporary Lake Lewis.
Erratics dropped by icebergs melting in the ocean can be used to track Antarctic and Arctic-region glacial movements for periods prior to record retention. Also known as dropstones, these can be correlated with ocean temperatures and levels to better understand and calibrate models of the global climate.[1]
^Bard, Edouard (June 2004). "Effet de serre et glaciations, une perspective historique" [Greenhouse effect and ice ages: historical perspective]. Comptes Rendus Geoscience (in French). 336 (7–8): 603–638. Bibcode:2004CRGeo.336..603B. doi:10.1016/j.crte.2004.02.005.
A glacialerratic is a glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from...
of Sec. 21, Township 20, Range 1, West 5th Meridian. Big Rock is a glacialerratic that is part of a 930 km (580 mi) long, narrow (1.00 to 22.05 km (0...
scouring and scratching, glacial moraines, drumlins, valley cutting, and the deposition of till or tillites and glacialerratics. Successive glaciations...
250 kilometres (150 miles) away in Wales, either through glaciation (glacialerratic theory) or through humans organizing their transportation. A summary...
period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology...
Stones of Scotland Glacialerratic boulders of Island County, Washington Glacialerratic boulders of King County, Washington Glacialerratic boulders of Kitsap...
Look up erratic in Wiktionary, the free dictionary. Erratic may refer to: Erratic, a project of music artist Jan Robbe Glacialerratic, a piece of rock...
the south(west). Features: strandlines along the valleys east flank. Glacialerratic on the grounds of the University of Montana Strandlines can be seen...
The Last Glacial Maximum (LGM), also referred to as the Last Glacial Coldest Period, was the most recent time during the Last Glacial Period where ice...
material upon which they are found. Patterns of glacialerratics hint at past glacial motions. Glacial moraines are formed by the deposition of material...
U-shaped subsection of the Laurentia craton signifying the area of greatest glacial impact (scraping down to bare rock) creating the thin soils. The age of...
Pennsylvania, which was founded by Quaker settlers from Soulbury. A glacialerratic lies in a road in the parish. The stone originated in Derbyshire, and...
Glacialerratic boulders of Estonia are large boulders of rock which have been formed and moved into Estonia by glacial action during previous ice ages...
The Last Glacial Period (LGP), also known colloquially as the Last Ice Age or simply Ice Age, occurred from the end of the Last Interglacial to the end...
features. Types of feature that the term has been applied to include: Glacialerratic A boulder that was transported and deposited by glaciers or ice rafts...
The Skystone is an andesite glacialerratic boulder in Bonney Lake, Washington. The boulder was deposited approximately 13,000 years ago. The stone's...
are glacialerratics that lie upon a surficial blanket of Late Wisconsin glacial till. The largest glacialerratic within the Foothills Erratics Train...
be built. In October 2017, at a depth of 10 m (33 ft), a 60 tonne glacialerratic was excavated at the construction site. It was pulled out using a specialized...
average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene interglacial began at the...
Omars, are a distinctive type of glacialerratic that consists of dark siliceous greywacke and exhibits prominent rounded, often deep, hemispherical voids...
event which marked a return to glacial conditions, temporarily reversing the climatic warming of the preceding Late Glacial Interstadial (also known as the...
are thus also more size sorted than glacial till is. The stone walls of New England contain many glacialerratics, rocks that were dragged by a glacier...
Wedgwood Rock is a glacialerratic (known to geologists as the Wedgwood Erratic) near the neighborhood of Wedgwood in Seattle, Washington. Its mineral...
describe long sinuous ridges, which are now known to be deposits of fluvio-glacial material. The best-known example of such an eiscir is the Eiscir Riada...
Many glacialerratic boulders (often simply called glacialerratics) can be found in the Puget Sound region as far south as the Yelm area where the Puget...
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