Santa Fe River 1 [Blancan]

University of Florida Fossil Vertebrate Localities CO003B, CO037B, and CO038B

Location

Santa Fe 1 is a 1000-yard-long (0.9 km) stretch of the Santa Fe River on the Columbia-Gilchrist county boundary, downstream of the town of High Springs and upstream of the State Highway 47 bridge. It is located in the vicinity of Ginnie Springs and the Devil’s Eye Spring. 29.84^o N, 82.70^oW.

Age

• Early Pleistocene Epoch; Blancan land mammal age
• About 2.3-2.6 million years old

Basis of Age

Vertebrate biochronology. The co-occurrence of Glyptotherium arizonae, Megalonyx leptostomus, Borophagus diversidens, Platygonus bicalcaratus, Capromeryx arizonensis, and Nannippus peninsulatus is limited to the Blancan land mammal age (Morgan and Hulbert, 1995). The presence of Paramylodon garbonii and the small size of the Holmesina floridanus and Dasypus bellus specimens further limit the age to the early part of the late Blancan (Hulbert 2012), making it one of the older late Blancan localities in the state.

Geology

Fossils are found in modern and Pleistocene deposits in the bed of the Santa Fe River from just upstream of High Springs to its point of confluence with the Suwannee River. As is the case with most fossils recovered in river beds in Florida, specimens of two or more different ages are found mixed together on the Santa Fe River: late Pleistocene, early Pleistocene, and Eocene. Santa Fe River 1 is one of three regions on the Santa Fe River where Blancan fossils are common, in some places more common that late Pleistocene specimens (the other two are Santa Fe River 4A and Santa Fe River 8). In other areas Blancan specimens are uncommon.

Santa Fe River 1 includes two small areas with in-place, fossiliferous Pleistocene sediment; these are called Santa Fe River 1A (UF Fossil Vertebrate Locality CO037) and Santa Fe River 1B (UF Fossil Vertebrate Locality CO038). Santa Fe 1A was long recognized as producing a mix of Blancan and Rancholabrean fossils, but Santa Fe 1B was originally thought to produce only Blancan specimens (Webb, 1974). However, later work has shown that it too produced some late Pleistocene, Rancholabrean fossils (MacFadden and Hulbert, 2009). Therefore, it is assumed that these deposits actually formed in the late Pleistocene, a time where a nearby early Pleistocene deposit was being eroded and its fossils were re-deposited with those of the late Pleistocene.

The original in situ source bed of the early Pleistocene fossils from Santa Fe River 1 has never been found and likely no longer exists. So its geology is unknown.

Depositional Environment

unknown

Fossils

The Florida Museum of Natural History has about 400 cataloged specimens from Santa Fe River 1 that are of Blancan age (including sites 1A and 1B). They primarily belong to species that are either limited to the Blancan or to the Blancan-early Irvingtonian. There are many hundreds of additional specimens that could be Blancan but might also be Rancholabrean and are not counted here or included in the faunal list. This includes species like Alligator mississippiensis which lived in both time intervals, and specimens which cannot be identified to the species level.

Excavation History and Methods

Santa Fe River 1 was discovered in 1962 by two amateur collectors, Ben Waller and Robert Allen, who brought the fossils they found scuba-diving to the attention of the Florida Museum of Natural History, then known as the Florida State Museum (Webb, 1974; Ray, 2005). Fossils were collected at this and other regions of the Santa Fe River during the early to middle 1960s by scuba-diving teams first led by Clayton Ray and then by S. David Webb, successive curators of Vertebrate Paleontology at the Florida State Museum. Because the Blancan age of many of its fossils, which at the time were uncommon in Florida, the Santa Fe River 1 area was heavily collected at this time. The most significant find was the first fossils of the giant flightless bird Titanis walleri.

In 1993, excavations were restarted at Santa Fe River 1, led by museum post-doc Robert M. Chandler with the main objective to look for more fossils of Titanis walleri (Chandler, 1994; MacFadden and Hulbert, 2009). Collectors dived and scoured the river bottom in the area believed to be the Santa Fe River 1B based on notes from the excavation that occurred in the 1960s, yielding numerous mammal and reptile fossils in addition to a few more examples of Titanis walleri.

Discussion

Santa Fe River 1 was the first fossil fauna in Florida known to produce Blancan-age specimens (Ray, 2005). In the 1960s, the chronologic ranges of mammalian species through the Pleistocene was not well understood, so the mixed nature of the Santa Fe 1B assemblage was not recognized. After Webb (1974) asserted that the Santa Fe 1B specimens were entirely Blancan, this was followed for several decades. Partial mammoth teeth were found there in the 1960s and many more by the Chandler expeditions in the 1990s, as well as two fairly complete juvenile teeth. Lambert et al. (1995) used these specimens as the basis to claim they were the oldest known mammoth teeth in North America, under the assumption that they were Blancan. This was later repeated by Lambert and Shoshani (1998). MacFadden and Hulbert (2009) tested this claim using rare earth elements (REEs). REEs are 14 naturally occurring metallic elements such as lanthanum and yttrium, that are present in exceeding low levels in the bones and teeth of living vertebrates. During the process of fossilization, the minerals in the fossils incorporate REEs into their crystals, with the relative proportions of the different REEs based on that found in the surrounding ground water. So fossils will almost always have greater concentrations of REEs than modern bone, although typically in the range of 10s to 100s parts per million. Fossils of two ages mixed together may show different relative proportions of REEs if ground water concentrations had changed between their times of fossilization. MacFadden et al. (2007) showed that the Rancholabrean and Blancan fossils from Santa Fe River 1 had different REE proportions. In their 2009 study, MacFadden and Hulbert compared REE levels from several mammoth teeth from Santa Fe River 1 with those from Blancan and Rancholabrean species. The REE concentrations for the mammoth teeth fell within the range of the Rancholabrean species and outside those from the Blancan. Other species from Santa Fe River 1 which in the past were regarded as Blancan but are now regarded as Rancholabrean are the giant beaver Castoroides and the manatee Trichecus (MacFadden and Hulbert, 2009).

Santa Fe River 1 produced most of the specimens of the canid Borophagus diversidens from Florida. This species is widely distributed during the Blancan in the central and western United States and Mexico but only from Florida east of the Mississippi (Wang et al., 1999). This species is the last member of the subfamily Borophaginae, which through much of the Miocene was the most diverse and dominant group of carnivores in North America. But only this single species remained to reach the early Pleistocene. It shows extreme modification of its teeth and skull for a diet composed largely of bones, similar to some modern hyenas (Wang et al., 1999).

Most of the known fossils of the giant flightless bird Titanis walleri come from either Santa Fe River 1 or the Inglis 1A site in Citrus County. A discussion on this fearsome predator and images of specimens can be found on its fossil species webpage.

Sources

• Original Author(s):  Richard C. Hulbert Jr.
• Original Completion Date:  March 13, 2015
• Editor(s) Name(s): Natali Valdes
• Last Updated: June 16, 2015

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