Mysteries abound in science, but few are as unique as that of
the Carolina Bays. The extraordinary beauty of these marvels is
that they are in our own backyard. North Carolina and this region
in particular, are home to many of the 500,000 Carolina Bays
scattered along the Atlantic seaboard.
What is a Carolina Bay? Carolina Bays are egg or oval-shaped
depressions in the regional geography, located along the eastern
states ranging from Florida to Maryland. They’re found in a
variety of sizes from as little as one acre up to several thousand
acres. To give you some perspective, Lake Waccamaw, North
Carolina’s largest bay, is just under 9,000 acres!!
Besides their common shape, each one of the Carolina bays is
angled in a northwest-southeast direction, perhaps providing some
clue as to their origin. Scientists find that the southeastern rim
of the bays is generally higher and composed of white sand. One
study(Ref 1) notes that this phenomenon might be as a result
of the open water freezing during prehistoric winters causing the
prevailing winds to drive the ice against the sandy shorelines,
but, alas, we may never know for sure. Confounding the study,
scientists find the orientation changes as one travels northward
until, in the most northern distribution of the bays, they’re
found in an almost random orientation suggesting no relationship at
all.
Because each of the bays vary in depth and substrate, their
ability to hold water is dependent on region, water source and
hydrology. Some bays are open, deep water lakes, others are marshes
or peat bogs, and still others are dry land retaining only the
Carolina Bay shape.
While the focus of this Earthcache is the geological feature,
one cannot overlook the biological diversity that surrounds many of
the Carolina Bays. The mix of ecosystems attracts a rich variety of
flora and fauna, many species of which are rare or endangered. As
you explore the park and facts on the bays, you’ll be
surprised to learn that the actual name “Carolina Bay”
has more to do with plant life and less to do with the fact that
some of these formations contain water.
How were they formed? No answer to this question is
conclusive. For as many clues offered by the Carolina Bays as to
their origin, there are an equal number of mysteries unsolved.
Theories include sea current action while this area was part of a
prehistoric ocean, impact or series of impacts from meteors, and,
my favorite,
“… the formation of siliclastic
karst by solution of subsurface material during glacial sealevel
lowstands and later modification of these depressions by periodic
eolian and lacustrine processes.”(Ref 2)
While the “Impact Theory” is exciting to think
about, the idea has lost ground since its popularity in the
1930’s and 40’s. The ratio of diameter to depth is not
consistent with meteor strikes, even if struck at low velocities.
The total lack of any extra-terrestrial fragments or materials is
even greater evidence that the bays formed in some other
way.
The more likely theory is that of the “siliclastic
karst” or dissolved rock. At some point in time, the
theory postulates, there was a great upwelling of this material.
Once on the surface, but still underwater, the atmospheric and
oceanic processes shaped the bays into what we see today.
Please enjoy the park and this Earthcache.
FTF Honors go to dleel!!
Jones Lake State Park Hours:
Nov – Feb 8 am to 6
pm;
Mar, Oct 8 am to 7 pm;
Apr, May, Sep 8 am to 8 pm;
Jun – Aug 8 am to 9 pm.
To log this Earthcache:
1. Please post a picture of
you, your GPS and the structure at these coordinates;
2. Please answer, taking a quote from the information in front of
you, “What can you view from this
location”?
3. And for a bonus question, What are the Carolina Bays
named after?
References for this listing:
1. “The Age and Trophic History of Lake Waccamaw, North
Carolina” by J. C. STAGER and L. B. CAHOON, Department of
Biological Sciences, University of North Carolina at Wilmington,
Wilmington, NC 28403. http://abob.libs.uga.edu/bobk/wacbay.html
2. http://en.wikipedia.org/wiki/Carolina_bays
3. “Jones Lake State Park Informational Guide”; NC
Division of Parks and Recreation, Department of Environment and
Natural Resources.
4. Park website: http://www.ncparks.gov/Visit/parks/jone/main.php
5. Diane Tennant series, The Virginian-Pilot, September
2008:
The Carolina bays: Explaining a
cosmic mystery;
Are Carolina bays related to the extinction of the mammoth?;
The Carolina bays: New evidence points to a killer comet