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ISSN 1556-6757 |
SJI |
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Volume
3, Issue 1, 2009
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The Zumberge Ice Shelf
Nolan B. Aughenbaugh
Abstract
During the maximum of Pleistocene glaciation in the northern
hemisphere, the greatest extent of the ice-sheet boundaries
has been portrayed as ending at the present continental
shorelines. Maps show the Labrador, Greenland, Iceland and
Eurasian ice sheets as separate masses. The author proposes
that these ice sheets coalesced to form one large ice sheet
as presently exists in Antarctica. It is proposed that the
southern extent of this ice sheet into the Atlantic Ocean
was a floating glacier known as an ice shelf similar to
those that exist in Antarctica. This ice shelf, the proposed
Zumberge Ice Shelf, was continuous from the United States
near Long Island to Great Britain. This distance is no
greater than the seaward lengths of the Ross and
Ronne-Filchner Ice Shelves in Antarctica. Data from Arctic
research findings in the northern Atlantic are presented to
support the Zumberge Ice Shelf existence. Recent
archeological findings in the eastern United States have
found that some of the earliest people to colonize North
America were from France and Spain. The Zumberge Ice Shelf
would provide an easy, safe and rapid way to make the
journey, rather than the use of open boats made of animal
skins to cross some 3,000 miles of the stormy North Atlantic
Ocean.
Full Article
Sedimentology and paleogeography of the Bakhtyari
Conglomeratic Formation at Ghalat and Garu –Charmakan
Mountains, NW of Shiraz, Iran, Mohammad Bahrami
Abstract
Conglomerate – the lithified equivalent of gravel - forms
nearly the whole Bakhtyari Formation, and alternates with
sandstone and mudstone in the upper parts of the Aghjari
Formation in the Folded Zagros Zone, and hence in the
studied region. In addition to some low and high anticlines,
the region consists of two elevated synclines reaching to
over 3000 meters. The synclines are parallel to each other
and, unlike in most of the Folded Zagros, overhang adjacent
anticlines. Polymictic conglomerates form excellent outcrops
in the central parts of these
synclines. From the viewpoint of its (coarse) clast
composition, the Bakhtyari Formation consists of two types
of conglomerates: 1. Limestone-Chert Clast-Supported
Conglomerate (LCCSC) and 2. Limestone Clast-Supported
Conglomerate (LCSC). The chronological and spatial
relationships between these conglomerates are not easily
determined due to existence of some thrust faults at their
approximate boundaries, and it seems that each has its own
independent chronological and spatial setting. In the
vertical succession, various lithofacies are recognized;
their textural characteristics and sedimentary structures
specify a non-marine depositional system and are considered
"standard" lithofacies of alluvial fans and braided rivers.
Epirogenic movements in the region began in the Oligocene,
indicated by a chert micro-conglomerate bed at the Jahrum –
Asmari Formation boundary. These movements then changed to
orogenic ones with the deposition of gravelly alluvium now
known as Aghajari (upper parts) and Bakhtyari Formations.
Full Article
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