The continental glaciations of the Pleistocene left signatures on the landscape in the form
of glacial deposits and landforms; however, the best knowledge of the magnitude and timing of the various glacial and interglacial periods comes from oxygen isotope records in ocean sediments.
Moraine Creek is certainly an apt name; it has carved through an impressive cake
of glacial deposits containing rocks of all origins and colors, ground together, mixed, and mashed by creeping glaciers.
Not exact matches
Bay mud consists
of thick
deposits of soft, unconsolidated silty clay, which is saturated with water; these soil layers are situated at the bottom
of certain estuaries, which are normally in temperate regions that have experienced cyclical
glacial cycles.
* Chinese
glacial deposits show that three
of the oldest and coldest ice ages in Earth's history date from 600 to 750 million years ago.
They consist
of blocks
of horizontally layered
glacial deposits, often complete with the overlying forest floor.
Lead author Martin Kennedy at the University
of California, Riverside, and colleagues collected limestone and dolomite rocks from Precambrain
glacial deposits in northern Namibia, central Australia and the North American Cordillera.
In fact, the Libyan Sahara Desert contains unmistakable
glacial scars and Antarctica has extensive coal
deposits — and very likely abundant oil and gas — that establish that their plates were once at the other ends
of the earth (see image at right).
The movement
of these large masses
of ice also leaves distinct marks on the walls
of valleys and in the form
of deposits of glacial sediment.
When he started inspecting nearby craters to work out the direction
of the sunlight and shadows, however, he realized that those channels weren't channels at all; they were ridges
of material and possible evidence for
glacial deposits.
Bartek, L.R., and Anderson, J.B., 1991, Facies distribution resulting from sedimentation under polar interglacial climatic conditions within a high - latitude marginal basin, McMurdo Sound, Antarctica: in J.B. Anderson and G.M. Ashley, eds., Paleoclimatic Interpretation
of Glacial Marine
Deposits, Special Publication 261, Geological Society
of America, Boulder, p. 27 - 49.
This is because terrestrial
deposits of ancient
glacial and interglacial periods1 — 3 are overrun and eroded by more recent
glacial advances, and are therefore usually rare, isolated and poorly dated.
The concentrations were lowest in the eastern and far western states where the soil had been tilled the longest, and were highest in Deaf Smith County, Texas, where excavations proved the roots
of the wheat grass to pass down six feet or more through three feet
of top soil into
deposits of glacial pebbles cemented together with calcium carbonate.
As the oceans levels rose,
glacial waters flowed through the limestone
deposits of the then exposed Lighthouse Reef resulting in huge subterranean caverns.
A group
of related photographs documents the enormous
glacial erratics that were
deposited around Pelham Bay.
You should ask your Tardlie friend what kind
of soil he expects to find in the north given that virtually all
of it was scraped off and
deposited north
of the 49th during the last
glacial period.
Major ice sheets, in particular in Greenland [8], ocean methane clathrate
deposits [9], and future evolution
of glacial / interglacial cycles [10] might be affected by that long tail.
Yellowstone's northern range
of sagebrush - grasslands and bison, elk, wolf, and bear inhabitants is founded on
glacial moraines, sub-
glacial till, and outwash
deposited during the last glaciation.
Examples
of this type
of data include tree ring width and density measurements, fossilized plant remains, insect and pollen frequencies in sediments, moraines and other
glacial deposits, marine organism fossils, and the isotope ratios
of various elements.
There are a number
of different types
of proxy data types in this group including
glacial deposits,
glacial erosional features, shoreline features, aeolian
deposits, lake sediments, relict soil
deposits, and speleothems (depositional features like stalactites and stalagmites).
We can determine the past climate
of the Earth by mapping the distribution
of ancient coals, desert
deposits, tropical soils, salt
deposits,
glacial material, as well as the distribution
of plants and animals that are sensitive to climate, such as alligators, palm trees & mangrove swamps.
Despite slow rates
of plant growth in the Arctic and sub-Arctic latitudes, massive
deposits of peat have accumulated there since the last
glacial maximum (Smith et al., 2004; MacDonald et al., 2006).
One author, speculating about the coming
of a new ice age, pointed to «evidence
of (at least) five rapid hemispheric coolings
of about 5 °C... each event spread over not more than about a century,» Flohn (1974), quote p. 385; one line
of evidence was carbon - 14 studies
of tree stumps in
glacial deposits: Denton and Karlén (1973).
Imputities are a main problem in Greenland ice cores where a mix
of seasalt / carbonate and acidic dust from Icelandic volcanoes can produce CO2 in situ, but is less
of interest in deep inland Antarctic ice cores, except during the deepest times
of glacials, when far more dust is
deposited.
Sohl, L.E., N. Christie - Blick, and D.V. Kent, 1999: Paleomagnetic polarity reversals in Marinoan (ca. 600 Ma)
glacial deposits of Australia: Implications for the duration
of low - latitude glaciation in Neoproterozoic time.
above: the calling - card
of an ancient ice - age - an outcrop in Namibia
of an ancient (Proterozoic) tillite
of glacial origin, overlain by a dolomitic «cap - carbonate» sequence
of marine origin,
deposited in warmer post-
glacial conditions.
The drill core penetrated 514 m
of silts and silty clays (
glacial deposits) punctuated by muds and episodic 0.02 — 1.2 m thick terrigenous sands (interglacial
deposits) 22.