Heroic Erratic Earthcache EarthCache
Heroic Erratic Earthcache
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This earthcache is located in a small park on Staten Island
overlooking a portion of New York harbor. Park safely on the west
side of Victory Boulevard in front of or near the marked bus stop
for those vehicles heading west and walk northeast from there.
This site is another in my series of Earthcaches, designed to
inform others about the geology of Staten Island, New York. Within
the park is a gigantic potato-shaped and vertically-oriented
glacial boulder. It is unofficially known as “Sugarloaf” after a
mountainous peak of similar shape located in Rio De Janeiro,
Brazil. This boulder was deposited here recently by the last
advance of a huge continental glacier known as the Laurentide Ice
Sheet, which came down from Canada during the Wisconsin Stage of
the Pleistocene Epoch within the Cenozoic Era, approximately 10- to
15-thousand years ago. Glacial ice carries anything and everything
that lies within its path from tiny grains of sand to large
house-sized boulders. During its transportation, it has become
rounded and polished by other debris within the glacial mass before
it was left behind in its current position by the melting ice. This
boulder is sticking only about half-way out of the ground! As the
glacial ice melted in a now warmer climate, all of the debris the
ice was carrying was eventually deposited on the land's surface.
The glacial debris generally reflects the geology of the areas the
ice crawled over and is known as “glacial moraine.” Large boulders
like this are out of place compared to the local geology and are
known as “glacial erratics.” Stand next to this monster and imagine
a mass of ice in the range of 500 feet above your head! This rock
is composed of the minerals milky quartz, pink and white feldspar,
silvery muscovite mica, and black hornblende. This was originally
an igneous intrusive rock known as granite. It later became
subjected to heat, pressure, and chemically active fluids via
metamorphism during the Grenville Orogeny or mountain-building
event and changed into a granite-gneiss or more specifically a
hornblende-granite-gneiss. This behemoth boulder is suspected to be
a small piece of the Storm King Granite from Bear Mountain in
upstate New York, which has been radiometrically dated by U/Pb
zircon methods to be approximately 1.17 billion years old! This
date goes back to the Proterozoic Era of the Precambrian Eon. In
the recent past, this boulder is the home of several metallic
plaques to honor the World War I veterans from Staten Island who
gave the ultimate sacrifice. These brass plaques were marred by
vandals but have been recently restored and replaced. To claim this
Earthcache email me the approximate size of this erratic (height
and diameter). Enjoy this small park and give the giant erratic a
friendly pat, it has traveled a long distance from its homeland!
Additional Hints
(No hints available.)