Little Salt Spring
Encyclopedia
Little Salt Spring is an archaeological
and paleontological
site in North Port
, Florida
, United States
. It is located directly off Price Boulevard between US 41 and I-75 adjacent to Heron Creek Middle School U.S. Route 41
in the city of North Port
. On July 10, 1979, it was added to the National Register of Historic Places
.
Little Salt Spring is a feature of the karst topography
of Florida, specifically an example of a sinkhole
. The numerous deep vents at the bottom of the sinkhole feed oxygen-depleted groundwater
into it, producing an anoxic
environment below a depth of about 3 m (9.8 ft). This fosters the preservation of Paleo-Indian and early Archaic artifacts and ecofacts, as well as fossil bones of the extinct megafauna
once found in Florida.
Originally it was thought that Little Salt Spring was a shallow freshwater pond, but in the 1950s SCUBA divers
discovered that it was a true sinkhole extending downward over 200 ft (61 m), similar to the cenote
s of the Yucatán Peninsula
(another karst region). The actual depth of the surface pond is forty feet with a central shaft dropping vertically to an inverted cone with a maximum determined depth at the outer edges of 245 feet. There are ledges around the wall of the cenote at 16 and 27 meters (90 feet) below the present water level.
The site has been owned by the University of Miami
since 1980 and is studied by Dr. John Gifford of the Rosenstiel School of Marine and Atmospheric Science
, University of Miami.
extending away from it are filled with moist, soft peat
. Hundreds of burials dating from 5,200 to 6,800 years ago have been found in the slough. As has happened in other wetland burials in Florida, such as at the Windover Archaeological Site
, brain matter survived in many of the skulls. In the 1970s the overturned shell of an extinct giant land tortoise was found on the 27 meter ledge. A wooden stake had been driven between the carapace
and the plastron, and there is evidence of a fire under the tortoise. It appears that the tortoise had been cooked in its shell. The radiocarbon
date for the wooden stake was 12,030 years ago, and for a bone from the tortoise, 13,450 years ago. Large numbers of human bones have been recovered from the spring itself, but were not collected under controlled conditions.
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...
and paleontological
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
site in North Port
North Port, Florida
North Port is a city in southern Sarasota County, Florida, United States. The population was 22,797 at the 2000 census. As of 2007, the population recorded by the U.S. Census Bureau is 54,308. It is part of the Bradenton–Sarasota–Venice Metropolitan Statistical Area...
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It is located directly off Price Boulevard between US 41 and I-75 adjacent to Heron Creek Middle School U.S. Route 41
U.S. Route 41
U.S. Route 41 is a north–south United States Highway that runs from Miami, Florida to the Upper Peninsula of Michigan. Until 1949, the part in southern Florida, from Naples to Miami, was U.S...
in the city of North Port
North Port, Florida
North Port is a city in southern Sarasota County, Florida, United States. The population was 22,797 at the 2000 census. As of 2007, the population recorded by the U.S. Census Bureau is 54,308. It is part of the Bradenton–Sarasota–Venice Metropolitan Statistical Area...
. On July 10, 1979, it was added to the National Register of Historic Places
National Register of Historic Places
The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...
.
Little Salt Spring is a feature of the karst topography
Karst topography
Karst topography is a geologic formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite, but has also been documented for weathering resistant rocks like quartzite given the right conditions.Due to subterranean drainage, there...
of Florida, specifically an example of a sinkhole
Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...
. The numerous deep vents at the bottom of the sinkhole feed oxygen-depleted groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
into it, producing an anoxic
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
environment below a depth of about 3 m (9.8 ft). This fosters the preservation of Paleo-Indian and early Archaic artifacts and ecofacts, as well as fossil bones of the extinct megafauna
Megafauna
In terrestrial zoology, megafauna are "giant", "very large" or "large" animals. The most common thresholds used are or...
once found in Florida.
Originally it was thought that Little Salt Spring was a shallow freshwater pond, but in the 1950s SCUBA divers
Scuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
discovered that it was a true sinkhole extending downward over 200 ft (61 m), similar to the cenote
Cenote
A cenote is a deep natural pit, or sinkhole, characteristic of Mexico and Central America, resulting from the collapse of limestone bedrock that exposes groundwater underneath...
s of the Yucatán Peninsula
Yucatán Peninsula
The Yucatán Peninsula, in southeastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel...
(another karst region). The actual depth of the surface pond is forty feet with a central shaft dropping vertically to an inverted cone with a maximum determined depth at the outer edges of 245 feet. There are ledges around the wall of the cenote at 16 and 27 meters (90 feet) below the present water level.
The site has been owned by the University of Miami
University of Miami
The University of Miami is a private, non-sectarian university founded in 1925 with its main campus in Coral Gables, Florida, a medical campus in Miami city proper at Civic Center, and an oceanographic research facility on Virginia Key., the university currently enrolls 15,629 students in 12...
since 1980 and is studied by Dr. John Gifford of the Rosenstiel School of Marine and Atmospheric Science
Rosenstiel School of Marine and Atmospheric Science
The Rosenstiel School of Marine and Atmospheric Science is a college and research institute for the study of oceanography and the atmospheric sciences within the University of Miami . It is located on a 16 acre campus on Virginia Key in Miami, Florida, USA...
, University of Miami.
Prehistoric human use
The water level in the spring has varied over time. Twelve to thirteen thousand years ago the ocean level was about 100 meters (more than 300 feet) lower than at present, drawing down the water table in Florida, and the water level in Little Salt Spring was 27 meters (90 feet) lower than at present. The basin around the spring and a sloughSwamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
extending away from it are filled with moist, soft peat
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
. Hundreds of burials dating from 5,200 to 6,800 years ago have been found in the slough. As has happened in other wetland burials in Florida, such as at the Windover Archaeological Site
Windover archaeological site
The Windover Archaeological Site is an Early Archaic archaeological site found in Brevard County near Titusville, Florida, USA, on the central east coast of the state. Windover is a muck pond where skeletal remains of 168 individuals were found buried in the peat at the bottom of the pond. The...
, brain matter survived in many of the skulls. In the 1970s the overturned shell of an extinct giant land tortoise was found on the 27 meter ledge. A wooden stake had been driven between the carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
and the plastron, and there is evidence of a fire under the tortoise. It appears that the tortoise had been cooked in its shell. The radiocarbon
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
date for the wooden stake was 12,030 years ago, and for a bone from the tortoise, 13,450 years ago. Large numbers of human bones have been recovered from the spring itself, but were not collected under controlled conditions.