- #1
Mat h physics
- 1
- 0
Who may know some details about the Carolina Bays?
http://en.wikipedia.org/wiki/Carolina_bays
or other odd formation on the earth.
http://en.wikipedia.org/wiki/Carolina_bays
or other odd formation on the earth.
In what information is one interested?Mat h physics said:Who may know some details about the Carolina Bays?
http://en.wikipedia.org/wiki/Carolina_bays
or other odd formation on the earth.
Mat h physics said:The formed by falling bodies, was reasonable until learning how shallow they are. What do U believe to be a rational explanation?
There is plenty of time for erosion and accumulation of organic matter. The fact that they fill with water means that rocks and minerals would be carried to the depressions and accumulate over time. Then vegetation would grow in the water or along the banks, and sooner or later die. Leaves from deciduous trees are shed annually, so they would accumulate in the water. Nor surprises there.Mat h physics said:Thank you for the links. Never heard the "dinosaur footprints" part before << post edited by Mentor >>
The formed by falling bodies, was reasonable until learning how shallow they are. What do U believe to be a rational explanation?
Mat h physics said:So I ran across this vid: http://www.youtube.com/watch?annotation_id=annotation_567977&v=1IrxFAFL-oc&feature=iv
It seems as though an event like that being replicated (w/ as sheet of ice) @ the 4min mark would make sense...
Mat h physics said:Who may know some details about the Carolina Bays?
http://en.wikipedia.org/wiki/Carolina_bays
or other odd formation on the earth.
DoggerDan said:Are they odd? Similar features are found throughout the world in low-lying coastal areas. Louisiana's swamps are very similar.
No one has yet invented an explanation which will fully account for all the facts observed.
Here is my explanation for why the Carolina bays are oval and oriented all in the same general direction, and why I think they have a glacial origin:
Glacial Kettles are formed by large blocks of relatively sediment-free(clearer) ice being carried along in an ice-mass that is more uniformly sediment laden (gravels, glacial till). When the ice-mass finally melts, it does not always melt at once, nor at the same rate. The motion of the whole ice-mass accounts for the oval shape of the bays. In areas where kettle lakes are more round than oval, one can assume that the containing ice-mass was in relative stasis, i.e.: not in motion when melting occurred.
A pingo-scar hypothesis was rejected because the topographic and hydrological conditions are lacking and water depths were insufficient to form pingo-scars
Carolina Bays. The Carolina Bays are a group of »500,000 highly elliptical and often overlapping depressions scattered throughout the Atlantic Coastal Plain from New Jersey to Alabama (see SI Fig. 7). They range from ≈50 m to ≈10 km in length (10) and are up to ≈15 m deep with their parallel long axes oriented predominately to the northwest. The Bays have poorly stratified, sandy, elevated rims (up to 7 m) that often are higher to the southeast. All of the Bay rims examined were found to have, throughout their entire 1.5- to 5-m sandy rims, a typical assemblage of YDB markers (magnetic grains, magnetic microspherules, Ir, charcoal, soot, glass-like carbon, nanodiamonds, carbon spherules, and fullerenes with 3He). …
Fig. 7. Aerial photo (U.S. Geological Survey) of a cluster of elliptical and often overlapping Carolina Bays with raised rims in Bladen County, North Carolina. …
…The largest Bays are several kilometers in length, and the overlapping cluster of them in the center is ≈8 km long.
Recent palaeomagnetic studies suggest that excursions of the geomagnetic field, during which the intensity drops suddenly by a factor of 5 to10 and the local direction changes dramatically, are more common than previously expected. The `normal' state of the geomagnetic field, dominated by an axial dipole, seems to be interrupted every 30 to 100 kyr; it may not therefore be as stable as we thought.
Recent studies suggest that the Earth's magnetic field has fallen dramatically in magnitude and changed direction repeatedly since the last reversal 700 kyr ago (Langereis et al. 1997; Lund et al. 1998). These important results paint a rather different picture of the long-term behaviour of the field from the conventional one of a steady dipole reversing at random intervals: instead, the field appears to spend up to 20 per cent of its time in a weak, non-dipole state (Lund et al. 1998).
betzalel said:In the last 10 years, geomagnetic specialists have found evidence of cyclic geomagnetic excursions (during a geomagnetic excursion the geomagnetic field develops multiple poles and the field intensity drops by a factor of 3 to 10). A geomagnetic excursion is capable of abruptly cooling the planet by Svensmark's mechanism. (The cooling pattern during an excursion is complicated as there are multiple poles formed which causes both increases and decreases in galactic cosmic rays (GCR) depending on the location of new temporary pole.)
There are geomagnetic excursions at the termination of the past interglacial periods and at the Younger Dryas.
The Carolina marks are overlapping, elliptical, with an axis that is alligned in the North west direction.
http://www.pnas.org/content/104/41/16016/suppl/DC1#F7
Quote:
Is the geodynamo process intrinsically unstable?
http://eprints.whiterose.ac.uk/416/
Dotini said:Thank you for a very interesting post.
I agree that a reduction of the geomagnetic field could cause cooling via the Svensmark mechanism. But I'm not the sharpest tool in box, and fail to see the connection to Carolina Bays. Could you be bit more explicit about this, please?
Respectfully yours,
Steve
Five monogenetic volcanoes within the Quaternary Auckland volcanic field are shown to have recorded a virtually identical but anomalous paleomagnetic direction (mean inclination and declination of 61.7° and 351.0°, respectively), consistent with the capture of a geomagnetic excursion. Based on documented rates of change of paleomagnetic field direction during excursions this implies that the volcanoes may have all formed within a period of only 50–100 years or less. These temporally linked volcanoes are widespread throughout the field and appear not to be structurally related. However, the general paradigm for the reawakening of monogenetic fields is that only a single new volcano or group of closely spaced vents is created, typically at intervals of several hundred years or more.
Also, we wish to recall that evidence of a correlation between archeomagnetic jerks and cooling events (in a region extending from the eastern North Atlantic to the Middle East) now covers a period of 5 millenia and involves 10 events (see f.i. Figure 1 of Gallet and Genevey, 2007). The climatic record uses a combination of results from Bond et al (2001), history of Swiss glaciers (Holzhauser et al, 2005) and historical accounts reviewed by Le Roy Ladurie (2004). Recent high-resolution paleomagnetic records (e.g. Snowball and Sandgren, 2004; St-Onge et al., 2003) and global geomagnetic field modeling (Korte and Constable, 2006) support the idea that part of the centennial-scale fluctuations in 14C production may have been influenced by previously unmodeled rapid dipole field variations. In any case, the relationship between climate, the Sun and the geomagnetic field could be more complex than previously imagined. And the previous points allow the possibility for some connection between the geomagnetic field and climate over these time scales.
Orbital Influence on Earth’s Magnetic Field: 100,000-Year Periodicity in Inclination
A continuous record of the inclination and intensity of Earth’s magnetic field, during the past 2.25 million years, was obtained from a marine sediment core of 42 meters in length. This record reveals the presence of 100,000-year periodicity in inclination and intensity, which suggests that the magnetic field is modulated by orbital eccentricity. The correlation between inclination and intensity shifted from antiphase to in-phase, corresponding to a magnetic polarity change from reversed to normal. To explain the observation, we propose a model in which the strength of the geocentric axial dipole field varies with 100,000-year periodicity, whereas persistent nondipole components do not.
betzalel said:Other researchers have, however, noted that the orbital parameters are not not physically capable of causing sufficient changes to the liquid core to cause the “geomagnetic dynamo” to initiate an excursion or to cause an increase the geomagnetic field intensity.
Abstract
Carolina bays are nearly ubiquitous along ~1300 km of the North American Atlantic Coastal Plain, but relatively few bays have been examined in detail, making their formation and evolution a topic of controversy. The Lake Mattamuskeet basin, eastern North Carolina, USA, is a conglomeration of multiple Carolina bays that form a >162 km2 lake. The eastern shoreline of the lake is made up of a 2.9-km-wide plain of parabolic ridges that recorded rapid shoreface progradation. The lower shoreface deposit contains abundant charcoal beds and laminae dated 6465–6863 cal yr BP, corresponding with initiation of a lacustrine environment in the eastern part of the lake. A core from the western part of the lake sampled a 1541–1633 cal yr BP charcoal bed at the base of the lacustrine unit, indicating formation of this part of the basin postdates the eastern basin. Lake Mattamuskeet has no relationship to the Younger Dryas or a linked impact event because rim accretion significantly postdates 12,000 cal yr BP. The shoreline progradation, and association of charcoal beds with the oldest lake sediment in both main parts of the basin, suggest that fire and subsequent hydrodynamic processes were associated with initial formation of these Carolina bays.
Cintos said:... The coastal-marine deposits seen across the Lake Mattamuskeet basin are there because the entire Albemarle/Pamlico Peninsula was likely submerged at 80ka, as noted in the QR paper.
Carolina Bays are oval-shaped depressions found in the coastal plain of the southeastern United States. They are typically filled with water and can range in size from a few meters to several kilometers.
The exact formation process of Carolina Bays is still a mystery, but there are several theories. Some scientists believe they were created by a large meteorite impact, while others suggest they were formed by glacial activity or wind and water erosion. More research is needed to determine the true cause.
Carolina Bays are found primarily in the states of North and South Carolina, but they can also be found in parts of Georgia, Virginia, and Maryland.
The age of Carolina Bays is also a topic of debate among scientists. Some believe they were formed during the last ice age, while others suggest they are much older and could potentially date back millions of years.
Carolina Bays are considered a geological mystery because of their unique shape and the lack of a clear explanation for their formation. The fact that they are found in such large numbers and spread out over a large area also adds to the intrigue surrounding these geological features.