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  #1  
Old 04-03-2001, 09:07 PM
anenquiringmind anenquiringmind is offline
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How deep is the actual land?

How far down does it go?
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  #2  
Old 04-03-2001, 09:19 PM
elmwood elmwood is offline
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I'm not familiar with Florida geology yet, but here in Central Florida, the land seems to be one massive sandbar. I've been to a lot of construction sites, and you'd be hard-pressed to find a pebble in the ground. Sand, clay and hardpan -- that's it. There's hills, but apparently they are just giant, immobile sand dunes.

Enlighten me.
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  #3  
Old 04-03-2001, 09:24 PM
MEBuckner MEBuckner is offline
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I think it pretty much goes all the way down.

To, you know, the center of the Earth. Or, if you look at it another way, all the way to the other side of the Earth. About 4,000 miles; or 8,000 miles; depending on how you look at it.

Maybe I'm missing something here. Could you please re-phrase the question?
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  #4  
Old 04-03-2001, 10:15 PM
Diceman Diceman is offline
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Do you mean how far down until you hit water? If that's the case, my understanding is that in southern Flordia you're never more than a foot or two above the water table.
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  #5  
Old 04-03-2001, 11:32 PM
anenquiringmind anenquiringmind is offline
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I see what you mean LOL,and ROFL and going."huh?"..,,after rereading the question I posted and considering how it "might read" to someone who doesnt have the foggiest idea what I was thinking about in the first place, it is, I suppose a question that needs to be rephrased.. or at the least given more details....

From pics, The Earth is this round solid
piece of dirt and rock etc.
But we know this land is surrounded by water.
There are parts and pieces hanging off,,ie Florida, Italy.
Are these areas just as deep as, say,,,, Utah?
Apparently they cannot build basements in Florida, so thats what got me started on this...

And while I'm at it, What about the islands like The Bahamas etc. are they all just as deep?
Yes,I suppose I wanted to know, in Florida how far down till you hit water. One poster answered by saying not very far, so thats why I am asking. Is Florida really just a hunk of sand protruding off the US?
How many miles deep is it? Am I making myself clear? Somehow I doubt it.
But any answers will be appreciated.
Thanks
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  #6  
Old 04-03-2001, 11:38 PM
anenquiringmind anenquiringmind is offline
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p.s.

It's times like these that I am incredibly grateful
that I dont have to identify myself....
know what I mean?
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  #7  
Old 04-03-2001, 11:53 PM
Montfort Montfort is offline
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My old home in Plantation, a suburb of Ft. Lauderdale, was about five feet above the water table. I remember this presented a problem when we had a six-feet deep swimming pool dug in the early 1980s.
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  #8  
Old 04-03-2001, 11:55 PM
Derleth Derleth is offline
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If Florida was just a hunk of dirty sand hanging off the southern end of Georgia, you'd think it would have fallen off and become a submarine hunk of dirty sand long before now. Look at all of the condos in Miami, a city that would be in extreme danger if Florida was in any danger of breaking away from the Union, so to speak. All of that cement and Geritol and silicone adds up, you know.

I don't think Florida is just hanging loose in the Caribbean. If you go down far enough, I'm sure you'll hit rock that does go all the way down to the [Dr. Evil voice] hot molten mag-ma [/voice] of the mantle. The water table is just where the land is saturated with groundwater, not necessarily having anything to do with the oceans. But then, I'm not a geologist.
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  #9  
Old 04-04-2001, 12:01 AM
malden malden is offline
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I'm not a geologist, but I seem to recall that deep down, the Florida peninsula is limestone. Mexico's Yucatan peninsula, southwest of florida across the gulf, is also limestone, but more porous, and therefore has far less surface water features than Florida. They make an interesting pair of landforms to compare & contrast. I have fuzzy memories of attending a talk from a visiting lecturer on this subject when I was in grad school.

Don't forget that "hitting water" when you dig doesn't mean you've reached the bottom of anything or that you've reached sea level-- you could be above or below sea level. You could pass through a hundred feet of salt water, then a thousand feet of dry rock, then five hundred feet of fresh water, then five miles of dry rock, then the earth's semi-molten mantle. "Semi-molten mantle" is fun to say out loud.
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  #10  
Old 04-04-2001, 07:23 AM
broccoli! broccoli! is offline
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FL resident checking in...

In Port Charlotte (worlds greatest percentage of people over 80 and not a good place to live if you're under 60) the average is 4 feet above the water table, but it ranges from 1 to 11. In tampa, the average is a bit higher, but it is more inland. St. Petersburg (the 'coast' of Tampa as many non-FL people see it) is more like Port Charlotte.

Basically the deeper inland you go, the higher you'll get. (Orlando actually has hills! ::gasp:: ) Related note: in order NOT to have to have Flood insurance on a newly built house, you need to be at the 11-12 foot mark (which is why filler is so expensive down here.)

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  #11  
Old 04-04-2001, 08:40 AM
ladybug ladybug is offline
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I did a quick search on Britannica.com and found this information about land elevation throughout the state:

Quote:
Florida is a low-lying plain, mostly less than 100 feet (30 m) above sea level, with its highest point a mere 345 feet (105 m) in elevation. Sedimentary deposits of sand and limestone cover most of the state, with areas of peat and muck marking where freshwater bodies once stood. Almost two-thirds of the state is covered by trees, and there are more than 1,700 streams and some 30,000 lakes. The contemporary topography has been largely molded by running water, waves, ocean currents, winds, changes in sea level, and the wearing away of limestone rocks by solution.
I have to go read for class now, but I'll see if I can find some more info later. Hope this helps!
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  #12  
Old 04-04-2001, 10:18 AM
toadspittle toadspittle is offline
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Quote:
Originally posted by anenquiringmind


From pics, The Earth is this round solid
piece of dirt and rock etc.
But we know this land is surrounded by water.
There are parts and pieces hanging off,,ie Florida, Italy.
Are these areas just as deep as, say,,,, Utah?
Apparently they cannot build basements in Florida, so thats what got me started on this...

And while I'm at it, What about the islands like The Bahamas etc. are they all just as deep?
Yes,I suppose I wanted to know, in Florida how far down till you hit water. One poster answered by saying not very far, so thats why I am asking. Is Florida really just a hunk of sand protruding off the US?
How many miles deep is it? Am I making myself clear? Somehow I doubt it.
But any answers will be appreciated.
Thanks
From the above descriptions, this is my understanding of how you envision florida: like a protruding board that juts out from the side of North America and floats atop the water. Underneath it is more open water--so that you could, say, drive a submarine westward under the east coast and surface in the Gulf.

If that's what you're getting at...it's not the case.

To get an idea of what the earth is like, take the moon. It's got mountains and valleys. Some parts are higher, some parts are lower. Now, dump zillions of gallons of water all over it. The water will flow to the low-lying areas, covering them over, and leave only the high areas above the waterline. The low-lying areas are now "oceans." Very large high plateaus are "continents". Lone mountains, far from those plateaus, are now "islands."

All of them go "all the way down." None are floating in any way; they're all attached to the moon from the bottom up.



If this is not what you're getting at, I apologize. If you were just referring to the high water table (i.e., water permeating the solid earth; not open water beneath solid ground), then the other posters have pretty well covered it.
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  #13  
Old 04-04-2001, 10:59 PM
thinksnow thinksnow is offline
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toadspittle beat me to it, but I was going to comment that it seemed the revised OP was operating under the impression that Florida was floating or something. In response to that, see above post by ts (not me=ts, toad=ts.)

One other note that might be worth pointing out: the oceans are only so deep, then they are land that has depth. The depth should continue to the "semi-molten-magma" that people seem so find of speaking of, too.
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  #14  
Old 04-05-2001, 12:41 AM
kniz kniz is offline
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There's a song with these words "How deep is the ocean, how high is the sky?" Lowell Thomas said "When you are over 80 everything reminds you of something". I'm not that old, but it is happening to me.
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  #15  
Old 04-05-2001, 07:56 AM
broccoli! broccoli! is offline
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Actually ToadSpittle, FL is kinda like a board floating on the water. FL is built on a mangrove root base, which is basically a big bed of calcium and magnesium (and sand and such.) Most of the 'dirt' in FL (we have no real dirt) has been transplanted here from other places.

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  #16  
Old 04-05-2001, 09:22 AM
toadspittle toadspittle is offline
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Yep. Marco Island has good examples of this. You can see the surrounding mangrove islands slowly being built up with silt into something resembling solid ground.

I believe the island also has the highest point in Florida--but the hill is actually a giant garbage heap of discarded shells, created by ancient Native Americans.
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  #17  
Old 04-05-2001, 10:01 AM
FairyChatMom FairyChatMom is online now
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Quote:
Originally posted by anenquiringmind
... Apparently they cannot build basements in Florida, so thats what got me started on this...
Ahem.

I live in Florida - just south of Jacksonville.
I have a basement.
My in-laws built a house not far from here - they had a basement.
Granted, both houses are built in the side of slopes, but they are basements nonetheless.
And when we were digging post holes, we came upon water about 3 feet down, but our back yard abuts a wetland preserve area and there's a small creek back there, so that explains that.

Carry on.
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  #18  
Old 04-05-2001, 10:20 AM
Jman Jman is offline
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Well, to get into a geologic standpoint: The continental crust is usually around 30 km deep, with some parts deeper, some shallower...oceanic crust is about 10km deep or so. Below that, you get into the Mantle, which is still solid rock, but it's very hot, and very compressed, so the rock isn't brittle, it flows. Below the mantle (deep in the earth's interior), is a fluid outer core...so if you wanted to say how deep do you go until you're floating on liquid? About halfway to the center of the earth. Below that is a solid inner core...etc. The earth is NOT one big chunk of rock.

Jman
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  #19  
Old 04-05-2001, 10:22 AM
howardsims howardsims is offline
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An interesting but unrelated side note.... Florida was once part of Africa.
When proto-continents collided years ago to form the super-continent Pangea, then pulled apart to form the continents we know today, Florida got stuck to the North American continent and was pulled loose from Africa.
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  #20  
Old 04-05-2001, 10:26 AM
screech-owl screech-owl is offline
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Okay, I spent hours reading this stuff, now your gonna see it.

All passages below are excepted from Atlas of Florida [Univeristy Press of Florida, 1992]:

pg. 20
Geologic Formations

(Oldest parts of Flordia to youngest)
[Counties are approximate, from what I can compare to a nice multishaded map to a contemporary map of Florida]

Eocene

Avon Park Formation - Chalky, fossilierous limestone and crystalline dolomite, source of dolomitic limestone, agricultural stone and road stone.

Crystal River Formation - Shallow marine limestone composed of large foraminifers and mollusks. It is an impotant source of high calcium limestone and is chief supply of road stone in Florida.

[This is primarily the "bend" of Florida - Dixie, Levy, Citrus counties and some of the more inland areas.

Oligocene
Marianna Limestone, "Bryam" Formation, Duncan Church Beds, Suwannee Limestone -

Includes shallow marine granular fossiliferous limestone, dolomitic limestones, marine sediments, dolomitic limestones, clays, impure limestones.

[Hernando and Pasco counties, as well as Taylor, Lafayette Swannee and the more inland areas. Also a thin strip across Walton, Washington and Jackson counties.]

Miocene

Chattahoochee Formation - Argillaceous and silty, sandy chalky limestone,
Chipola Formation - Bluish gray to yellowish brown fossiliferous marl,
Shoal River Formation - Fossiliferous, micaceuous, slightly clayey and silty sand,
St. Marks Formation - Sandy, chalky limestone
Arcadia Formation - Sandy limestones with minor phosphates,
Coosawhatchie Formation - Phosphoritic clays and argillaceous and sandy limestones,
"Alachua" Formation - Clay, sand, sandy clay; in Gilchrist County, contains a vertebrate fauna that is one of the most prolific Miocene faunas in the US.
Peace River Formation - Phosphatic boulders and pebbles in matrix of phosphatic sandy clay (source of Florida's phosphate deposits),
Hawthorn Group/Peace River Formation - Marine sands, clays, marls and sandy limestone,
Yellow River Formation - Dark gray to bluish micaceous sands,
Red Bay Formation - Gray sandy and clayey shell marl.

[Now we get into scattered ares of Florida - Hillsborough, Polk, Manatee, Hardee, Sarasota counties as one block, scattered parts of Sumter, Alachua, Bradford, Madison and Hamilton, in the central northern part of the state, from Leon and Gadsden across to northern Walton in the panhandle, as well as Lee, Collier and Glades counties in the southwest.]

Pliocene -

Tamiami Formation - Creamy white limestone, greenish grey marls, silty sands, and clay
Miccosukee Formation - Silty clayey quartz sand
Citronelle Formation - Sand, gravels and clay
Cypresshead Formation - Marine sand, clay and gravel in pennisula

[This is several parts of the state - a long strip from Putnam, straight through to Highlands county, Leon to Hamilton across the northern part, near the border, and most of the western panhandle, Escambia to Walton counties]

Pleisocene -

Caloosahatchie Formation, Ft. Thompson Formation, Key Largo Limestone, Miami Limestone, Anastasia Formation

In south Florida, the Pleistocene is represented by limestone, shell hash, clay and sand.

[Most of the rest of south Florida, from Lake Okeechobee, southward, and the strip of the east coast from St. Lucie to Flagler counties.]

Late Pleistone and recent

Several marine and estuarine deposits - Freshwater marls, peats, snads, muds, now forming in stream valleys and fresahwater lakes and marine sediments accumulating along shorelines and shelves of the Gulf of Mexico and the Atlantic Ocean.

[Most of the eastern central region from Okeechobee to Baker and Nassau counties, as well as the Bay region (Wakulla westward to Bay and Walton counties, and a significant strip of Santa Rosa counties.]

pg. 21
Stratigraphic Nomenclature of Florida

There is a wonderful chart detailing the differences between the panhandle and the peninsula in rocks, beds and formations, starting with the Precambrian and the Paleozoic (Highly altered igneous rocks, granite, diorite, quartzitic sandstone and black shales as the base of the state). I am not going to quote it here (lunch time!), but there is a quote:

In Florida, as in many other places, rocks are not in a simple "layer cake" pattern. Different parts of the state have distinctive rosk sequences. Florida is built primarily out of layered rocks, but the geology of the should not be thought of as a huge book (with many layers of paper). Rather the state is more like a disorderly pile of many books.

[Insert your own 'governmental organization' joke here.]

pg. 22
Basement Geology
(Still typing on my lunch!)

The maps on this page detail Principal Structures (arches, embayments, synclines and anticlines), as well as further detailing distributions of Jurassic volcanics, Triassic igneous rocks, and Ordovician sediments. Quite fascinating, actually.

I am still trying to figure out the paleogeography section, regarding a 'northward migration' of Florida, from what seems to be from below the equator in the Permian, to just above the equator in the triassic, to about 20N in the Jurassic, to just below its present location in the Cretaceous to its present position (crossing 30N). Gonna re-read that over lunch.


Tell you what - contact me off board, and send the maps to you.

Oh, and the highest natural point in Florida - 345 feet near Lakewood in northeast Walton County.

Geographic center of the state - 12 miles northwest of Brooksville, Hernando County.
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  #21  
Old 04-05-2001, 10:48 AM
yabob yabob is offline
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Quote:
Originally posted by toadspittle
Yep. Marco Island has good examples of this. You can see the surrounding mangrove islands slowly being built up with silt into something resembling solid ground.

I believe the island also has the highest point in Florida--but the hill is actually a giant garbage heap of discarded shells, created by ancient Native Americans.
The highest point in Florida is generally given as Britton Hill (345 feet), near Paxton and the Alabama border in the panhandle. 300 feet would be one hell of a garbage pile.

And there's lots of places you can't build basements, or at least not without installing sump pumps and things like that.

"How deep is the Ocean?" was by Irving Berlin. One presumes he would not have appreciated a factual answer - Hey, Irving, about 7 miles at the Marianas Trench, and about 50 miles to the ionosphere ...
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  #22  
Old 04-05-2001, 01:32 PM
toadspittle toadspittle is offline
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My bad. It's the highest pt. in southwest Florida.

Quote:
Marco Island is the largest of the Ten
Thousand Islands, measuring about 24
square miles. The highest elevation in S.W.
Florida is right here on Marco - at Indian Hill,
we are 51 feet above sea level.
( http://www.marcoislandonline.com/visitor.htm )

It's still a pretty amazing pile of trash.
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