Ecology of South Florida (EVR 3013) LECTURE 4
GEOLOGY AND SOILS
To understand the Everglades one must first understand the rock... The rock beneath Lake Okeechobee is only a few feet above sea level. The surface of the lake is only 21 feet above the level of salt water. The surface rock of the everglades dips south at an incline of half a foot to every six miles. The rim of rock that retains it is narrower and higher on the east coast, but in the west it is hardly visible at all. There is a broad space of inland swamps and prairies and coastal sandy land and salt-invaded marshes. Yet both hold against the sea.
The rock is by no means the oldest in the world. It is nothing like the perdurable granite in the ancient Appalachian spine of the eastern continent. The material of it came from the sea. Out of reach of air it is lumpy, soft permeable limestone, grayish white, unformed. They call it "oolitic limestone" because it is no more fused together than a lot of fish eggs. In the sun and air it hardens in clumps and shapeless masses, dark, or gray, or yellowish, all full of holes, pitted and pocked like lumps of rotting honeycomb. It in itself shows no foldings or stratification, but holds streaks of sand or shells or pockets of humus.
M.S. Douglas (p. 17)
HANDOUTS:
- Fig. 4-1. Geologic Map--As a Bitmap, As a Gif
- Fig. 4-2. Silver Bluff Map
- Fig. 4-3. Soils Map.
I. GEOLOGIC TIME SCALE
| Era | Period | Epoch | Began |
|---|
| Cenozoic | Quaternary | Recent | 5,000 years ago |
| Pleistocene | 2.5 million years ago |
| Pliocene | 7 million years ago |
| Miocene | 26 million years ago |
| Tertiary | Oligocene | 38 million years ago |
| Eocene | 54 million years ago |
| Paleocene | 65 million years ago |
| Mesozoic | Cretaceous | | 136 million years ago |
| Jurassic | | 190 million years ago |
| Triassic | | 225 million years ago |
| Paleozoic | Permian | | 280 million years ago |
| Carboniferous | | 345 million years ago |
| Devonian | | 395 million years ago |
| Silurian | | 430 million years ago |
| Ordovician | | 500 million years ago |
| Cambrian | | 570 million years ago |
| Precambrian | | | 4600 million years ago |
II. SEA LEVEL CHANGES
A. 100,000 years ago | +8 m (Pamlico Sea) |
B. 17,000 years ago | -135 m |
C. 5,000 years ago | -5 m (rising at 2.6 mm/year) |
D. 3,200 years ago | -1 m (rising at 0.4 mm/year) |
E. May have oscillated | for the past 6,000 years |
| Period | Epoch | Age | YBP | Deposition | Terrace | Sea Level |
|---|
| Quaternary | Holocene | (intergl) | 0 - 10 K | | | rising |
| Pleist. | Wisconsin (gl) | 10 - 67 K | Erosion | | low |
| Sangamon (interglacial) | 67 - 128 K | Qm, Qa, Qkl | Princess Ann | +6 m |
| | | Pamlico | +8 m |
| Illinosian (gl) | 128 - 180 K | Erosion | | low |
| Yarmouth
(interglacial) | 180 - 230 K | Qft | Talbot | +12 m |
| | | Penholoway | +21 m |
| Kansan (gl) | 230 - 300 K | Erosion | | low |
| Aftonian(intergl) | 300 - 330 K | Qc | Wicomico | +27 m |
| Nebraskan (gl) | 330 - 470 K | Qc | Okeefenokee | +37-43m |
| unnamed | 470 - 2,000 K | Qc | | |
| Tert. | Pliocene | | 2,000 - 5,000 K | Pt & Pc | | |
III. GENERAL CHARACTERISTICS
A. South Florida is underlain
by ca. 20,000 feet of shallow marine carbonate sediments from Jurassic to Holocene. These occur above a mantle of volcanic rocks.
B. All sediments occur within the south Florida Basin,
bounded on NE by the Peninsular Arch, on the NW by the Ocala Uplift, on the W by the S. Florida Escarpment and on the South by the Straits of Florida
C. Tectonic activity minor
D. Deep stratigraphic sections
elucidated by oil exploration in the late 1940's. Sunniland Formation chief oil producing formation. Oil first discovered in the Sunniland Formation by Humble Oil Company on 1 Nov 1943.
IV. STRATIGRAPHY
A. Formations
- Qml- Miami Limestone
- Qa - Anastasia formation
- Qft - Fort Thompson formation
- Qc - Caloosahatchee Formation
- Pt - Tamiami Formation
- Qmt - several marine and estuarine deposits
B. Pliocene
1. Tamiami Formation
a. Buckingham Limestone
marl a mixture of lime mud, quartz sand, shell and rock fragments
b. Ochopee Limestone
limestone w/ various proportions of quartz sand, also freshwater limestones
c. Pinecrest Sand
quartz sand often with abundant shell, freshwater limestones, 3.5 - 4 million B.P.
2. Caloosahatchee Formation
variable
1.8 - 1.9 million years old
C. Pleistocene
1. Ft. Thompson marine limestones
- vary from shell beds to marls and mudstones, many fossil shell beds contain more than 50% quartz sand, also freshwater limestones, 134,000 - 324,000 BP
2. Miami limestone or oolite
- predominantly oolitic limestone, contains some quartz particularly in the northern areas, shows some cross bedding, extremely high porosity and permeability, 134,000 - 180,000 BP
3. Key Largo Limestone
- coraline limestone from Soldier Hey to Bahia Honda upper part 120,000 B.P., relict coral reef
4. Anastasia Formation
- coquina, sand, sandy limestone and shelly marl, up to 100' thick near the coast and thins to the W.
V. ENVIRONMENTAL AND ECONOMIC GEOLOGY
A. Environmental Geology
peat and limestone, fine sands and shelly sands
B. Economic Geology
limestone, sand and gravel, and oil
VI. INTRODUCTION TO SOIL SCIENCE
A. Definitions
1. soil
(pedalogic definition) a natural product formed from weathered rock by the action of climate and organisms (Thomson and Troeh 1973)
2. soil
(edaphic definition) a mixture of mineral and organic matter capable of supporting plant life.
B. Soil Structure
1. Organic horizons
(at least 20% - 30% organic matter)
O horizon - layer formed above mineral horizon, dominated by organic material
2. Mineral Horizons
(less than 12% - 18% organic matter)
- A horizon - layers of organic matter accumulation at or near the soil surface, eluvial
- B horizon - generally below an A horizon, zone of illuvial concentration of silicate clay, iron, aluminum, or humus
- C horizon - mineral horizon, excluding bedrock below root zone, rock or sediments
3. Parent Rock
R horizon - underlying bedrock
C. Soil Formation
(Jenny 1941)
S = f (cl, o, r, p, t)
where s= soil, cl = climate, o = organisms, r = topography, p= parent material, t = time)
D. Soil Properties
- texture, bulk density, pH, CEC, base saturation, chemistry
VII. SOIL CLASSIFICATION
A. USDA system
- hierarchical like botanical nomenclature
[order, suborder, great group, subgroup, family, series]
B. Soil Orders
- Entisols(recent)
- Vertisols (invert)
- Inceptisol (inception)
- Aridisol (arid)
- Mollisol (mollify)
- Spodsol (spodos-ash)
- Alfisol (pedlafer)
- Ultisol (ultimate)
- Oxisol (oxide)
- Histisol (histology)
VIII. FLORIDA SOILS
A. Four common orders
in southern Florida
1. Spodosols
mineral soils with a spodic horizon (organic matter, aluminum and iron oxides. Mostly acid coarse-textured. eg., aquods.
2. Histosols
organic soils. eg., saprist
3. Entisols
recent mineral soils with little horizon differentiation. eg., psamments
4. Alfisols
moist mineral soils lacking mollic or spodic horizons. Good agricultural soils. eg., udalfs
5. Miscellaneous coastal soils
B. Sample descriptions of series
1. Basinger Fine Sand
(2.9%) - Sileceous, hyperthermic spodic psammaquent. Nearly level, poorly drained, sandy soil in broad, low sloughs and depressions. Water table within 10" of the surface for 2-6 months of the year, permeability high, om content low
Order Entisol
Suborder Aquent
Great group Psammaquent
Subgroup Spodic psammaquent
Family Hyperthermic Spodic Psammaquent
Series Sileceous, hyperthermic spodic psammaquent
3. Immokalee Fine Sand
(2.8%) - Haploquod, nearly level, poorly drained, deep, sandy soil that has a dark colored layer below a depth of 30" that is weakly cemented with om, water table within 10' of the surface 2-4 months of the year
4. Lauderhill Muck
(2.6%) - Medisaprist, nearly level, poorly drained, organic soil that rests on limestone at a depth of 20-36", found in broad, freshwater marshes
C. Palm Beach
- Pahokee Muck (24.4%) - Medisaprist
- Terra Ceia Muck (21.0%) - Medisaprist
- Riviera Sand (6.3%) - Glossaqualfs
- Myakka Sand (4.1%) - Haplaquod
- Torry Muck (3.9%) - Medisaprist
- Basinger Fine Sand (2.9%) - Psammaquent
- Boca Fine Sand (2.8%) - Ochraqualf
- Immokalee Fine Sand (2.8%) - Haploquod
- Lauderhill Muck (2.6%) - Medisaprist
D. Broward
- Hallandale Fine Sand (13%) - Psammaquent
- Lauderhill Muck (12.8%) - Medisaprist
- Margate Fine Sand (11.0%) - Psammaquent
- Immokalee Limestone (5.8%)
- Dania Muck (5.7%) - Medisaprist
- Immokalee Fine Sand (3.5%) - Haploquod
- Plantation Muck (2.7%) - Medisaprist
E. Dade County
- Krome Loam (9.5%) - Udorthent
- Lauderhill Muck (7.9%) - Medisaprist
- Dania Muck (6.5%) - Medisaprist
- Perrine Marl (5.7%) - Fluvaquent
- Pahokee Muck (3.8%) - Medisaprist
- Biscayne Marl (2.8%) - Fluvaquent
- Chekika Loam (2.7%) - Udorthent
Back to start, Back to lecture 1, 2, 3, On to lecture 5, 6, 7, 8 & 9
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