The Lubbock Lake Fossil Site

 

Lubbock Lake was a natural 10 acre body of water located within the city limits of Lubbock, Texas.  Wind blown sediment formed a barrier that choked the flow of a stream, creating this lake.  Springs fed the stream and were part of the headwaters of the Brazos River system.   During the 19th century Lubbock Lake served as a favorite watering hole for cowboys and their cattle, and Indians had utilized these wetlands for at least 13,000 years.  But during the 1930s too many residents had dug wells in the vicinity causing the water table to drop and the lake to dry up.  City workers dug into the dry lake bed in a failed attempt to establish a reservoir.  However, vertebrate fossils and artifacts were found in the spoil piles of dirt dug by the engineers.  Scientists began studying this locality.  Material from this site was the first ever to be radio-carbon dated.  It’s the only site where evidence humans butchered giant short-faced bear and pampathere has ever been found. In 1987 Eileen Johnson published an extensive study of all the data compiled from this site.  That’s the source for the information I write about in this blog entry.

Location of the Lubbock Lake Fossil Site.  There is a museum administered by Texas Tech near the site which is also known as the Lubbock Lake Landmark.

Scientists looked for fossil pollen throughout the 300 acre area around Lubbock Lake.  They wanted to determine what the environment of the area had been like over the past 13,000 years.  They had a hard time finding enough pollen to establish a statistically valid pollen data base.  Some pine and spruce pollen was found in Pleistocene-dated samples, but scientists can’t agree on interpretations of the meager data they do have.  Some plant macrofossils were found in Pleistocene-dated sediments–bulrush, spike rush, seepweed, and netleaf hackberry.  This indicates the immediate vicinity of the stream was a brushy marsh.

Fossil remains of netleaf hackberry (Celtis reticulate) were found in Pleistocene-aged sediments at Lubbock Lake.  It is a small tree adapted to arid climates.

One scientist analyzed the composition of snail species to determine how the local environment has changed over the past 13,000 years.  Pleistocene-aged strata held 46 species, including 29 land and 17 aquatic snails.  All of the aquatic species can still be found in the region, but 3 species of land snails no longer occur here.  The silky vallonia (Vallonia cyclophorella) and the moss chrysalis snail (Pupilla muscorum) no longer range this far south.  Vertigo gouldi basidens (a snail with no common name) is currently restricted to high elevations in Colorado, Montana, and New Mexico.  The retreat of these 3 species from the Lubbock Lake site suggests a cooler moister climate existed here during the Late Pleistocene.

The moss chrysalis snail (Pupilla muscorum).  Shells of this species were found in Pleistocene-aged strata at this site.  It no longer ranges this far south.

The composition of the vertebrate fossils found in the Pleistocene-aged strata indicates the southern high plains environment was mostly grassland and desert with some brush and wetland habitats.   There are no representative species definitively representative of woodland or forested habitats, so I doubt pine and spruce trees were present in significant numbers.  Mammoth, bison, horse, camel, pronghorn, prairie dog, ground squirrel, jack rabbit, desert cottontail, burrowing owl, and tortoise prefer arid prairie habitat.  Herds of bison and pronghorns drank from Lubbock Lake until the end of the 19th century.  Based on this faunal composition, I believe the environment has changed little at this location since 13,000 years ago, though summers have gotten much hotter than they were during the Ice Age.

Eight species of extant vertebrates that lived near Lubbock Lake during the Late Pleistocene no longer occur here.  Meadow voles, southern bog lemmings, and prairie voles can’t tolerate the present day summer temperatures that can reach 100 degrees F.   Richardson’s ground squirrels have retreated to higher elevations.   Box turtles and common garter snakes can’t endure high heat without the shade of trees.  Eileen Johnson believes late Pleistocene summer temperatures here were on average 10 degrees F cooler than those of the present day.  There was also more frequent cloud cover.  I agree with this assumption but disagree with her assumption that Ice Age winters here were frost free.

She bases this belief on the presence of giant tortoise and pampathere (a species of giant armadillo) in the fossil record.  She assumes neither species could have survived a frost.  She stated they both were too large to have dug burrows that would have helped them escape freezing temperatures.  This is a curious assumption–grizzly bears grow larger than pampatheres, and they dig dens.  Since Dr. Johnson’s study was published, evidence pampatheres dug burrows has been found in southern Brazil, demonstrating they could have survived freezing temperatures by digging burrows.  And on previous blog posts, I’ve challenged the widely held assumption that giant tortoises couldn’t survive subfreezing temperatures. (See:https://markgelbart.wordpress.com/2011/04/15/the-extinct-pleistocene-giant-tortoise-hesperotestudo-crassicutata-must-have-been-able-to-survive-light-frosts/)  The giant tortoises were closely related to gopher tortoises, a species that does dig burrows; and I’m unaware of any anatomical studies that determined whether or not the giant tortoises were capable of digging.  Moreover, giant tortoises could have utilized burrows dug by giant ground sloths or pampatheres.  I believe winter temperatures at Lubbock Lake during the Ice Age were the same or just slightly milder due to greater cloud cover than those of the present day.

The most unusual vertebrate fossil found at Lubbock Lake was a specimen of the gray-breasted crake (Laterallus exilis), a bird that is presently restricted to parts of Central and South America.  During the Ice Age large lakes were abundant in southwestern North America because glacially cooled air collided with hot desert air, resulting in increased precipitation and cool cloudy conditions.  The gray-breasted crake prefers grassy marshes adjacent to lakes.  This bird along with many other species of waterfowl occurred in great numbers along these lakeshore habitats.  Wandering flocks and individuals of these species also populated the more meager wetlands found on the southern high plains, the region adjacent to the land of great lakes.

Remains of gray-breasted crake were found at the Lubbock Lake site.  This was the most surprising faunal find at this site.  Today, the range of this species includes parts of Central and South America.

Map of Pleistocene lakes in southwestern North America.  Cooler summer temperatures meant lower evapotranspiration rates, resulting in these abundant lakes then.  This probably explains the  occurrence of several aquatic bird species found in Pleistocene-aged strata at Lubbock Lake.

Several areas within the Lubbock Lake site have been interpreted as megafaunal meat processing stations. A station buried in Late Pleistocene sediment was used by members of the Clovis Culture.  They apparently butchered mammoths, bison, horse, half-ass, camel, giant short-faced bear, pampathere, turtles, and turkey here.  They butchered a 25 year old mammoth along with 2 juveniles.  A camel leg bone was broken and gouged for marrow.  Ribs of bison, camel, and horse showed evidence of de-fleshing.  A bear bone had knife cut marks on it, and the Indians actually made a tool from a bear bone. Eighteen shells of a large extinct subspecies of box turtle found here show evidence of human modification.  I should note that not all anthropologists agree with Dr. Johnson’s interpretation.  Some think stream action rolling bones against rocks can mimic the marks made by humans using stone blades.

This is the only known evidence that humans exploited Arctodus simus–the giant short-faced bear. There are knife cut marks on this bear’s leg bone. From the below referenced work.

Assorted Bison antiquus bones.  This was the evolutionary predecessor to the modern bison.  The Lubbock Lake site has been interpreted as a game processing station used by  paleoindians as well as archaic, ceramic, Apache, and Comanche Indians.

These are radio-carbon dates of associated organic material where these Paleo-Indian arrowheads were found.  Add about 2000 years for actual calendar year dates.

There is also plenty of evidence that later Folsom, Plainview, Highview, Archaic, Ceramic, Apache, and Comanche Indians also used this site to process game.  The Lubbock Lake site has long been the only reliable source of water for miles.  This explains why it’s an excellent archaeological site with representative artifacts from every culture that’s lived in the region for the past 13,000 years.

Below is the list of vertebrate species found here in strata dated to between 13,000 BP- 10,000 BP.

garfish–Lepisosteus sp.

quillback–Carpoides cyprinus.  This is a type of buffalo fish.

bullhead catfish–Ictalurus amieurus

black bullhead catfish–Ictalurus melas

channel catfish–Ictalurus punctatus

white bass–Morone chrysops

green sunfish–Lepomis cyanellus

warmouth sunfish–L. gulosus

unidentified darter–Percina sp.

tiger salamander–Ambystoma tigrinum

Couch’s spadefoot toad–Scaphiophus couchi

unidentified spadefoot toad–plains or western, Scaphiophus bombifrons or S. hammondi

cricket frog–Acris crepitans

plains toad–Bufo cognatus

woodhouse’s toad–B. woodhousei

bullfrog–Rana catesbiani

pickerel frog–R. palustrus

leopard frog–R. pipiens

snapping turtle–Chelydra serpentine

pond slider–Chrysemys scripta

Wilson’s tortoise–Geochelone?  wilsonii (extinct)

extinct giant tortoise–Hesperotestudo sp.

extinct subspecies of eastern box turtle–Terrapene Carolina putnami

ornate box turtle–T. ornate

soft-shelled turtle–Trionyx sp.
Texas horned lizard–Phrynosoma cornutum

Great plains skink–Eumeces obsoleteus

black racer–Coluber constrictor

worm snake–Carphophis amonus

corn snake–Elaphe guttata

western hook-nosed snake–Gyalopion canum

western hog-nosed snake–Heterodon nasicus

king snake–Lampropeltis getulus

milk snake–L. triangulum

unidentified water snake–Nerodia sp.

red bellied water snake–N. erythrogaster

unidentified snake in the Elaphe or Pituphis genus

patch-nosed snake–Salvadora sp.

ground snake–Sonora semiannulata

checkered garter snake–Thamnophis marcianus

common garter snake–T. sirtalis

lined snake–Tropidoclonion lineatum

rough earth snake–Virginia striatula

copperhead snake–Agkistrodon contortix

western diamondback rattlesnake–Crotalus atrox

eared grebe–Podiceps nigricollis

pied-billed grebe–Podilymbus podiceps

Canada goose–Branta Canadensis

snow goose–Anser caerulescens

mallard duck–Anas platyrhincus

gadwall or pintail duck–A. streptera or A. acuta

pintail duck–A. acuta

northern shoveler–A. clypeata

green winged teal–A. crecca

blue-winged teal-A. discors

cinnamon teal–A. cyanoptera

ruddy duck–Oxyura jamaicensis

marsh hawk–Circus cyaneus

unidentified galliforme–either a prairie chicken or sharp-tailed grouse

turkey–Meleagris sp.

Virginia rail–Rallus limicola

clapper rail–R. longirostris

sora rail–Porzana Carolina

gray-breasted crake–Laterallus exilis

common gallinule–Gallinula chloropus

coot–Fulica Americana

mountain plover–Charadrius montanus

burrowing owl–Athene cunicularia

common nighthawk–Chordeiles minor

northern flicker–Colaptes auratus

horned lark–Eremophilia alpestris

common raven–Corvus corvax

mockingbird–Mimus polyglotis

red-winged blackbird–Agelaius phoenicus

brown-headed cowbird–Molothrus ater

vesper sparrow–Poocetes gramicus

unidentified shrew–Blarina sp.

desert shrew–Notiosorex crawfordi

pampathere–Holmesina septentrionalis

desert cottontail–Sylvilagus audubonii

blacktail jackrabbit–Lepus californicus

Richardson’s ground squirrel–Spermophilus richardsonii

13-lined ground squirrel–S. tridecemlineatus

Mexican ground squirrel–S. Mexicanus

blacktail prairie dog–Cynomys ladovicianus

valley pocket gopher–Thomomys bottae

plains pocket gopher–Geomys bursarius

hispid pocket mouse–Perognathus hispidus

Ord’s kangaroo rat–Dipodomys ordii

plains harvest mouse–Reithrodontomys montanus

cactus mouse–Peromyscus eremicus

unidentified field mouse–Peromyscus sp.

northern grasshopper mouse–Onychomys leucogaster

southern plains woodrat–Neotoma micropus

white-throated woodrat–N. albigula

cotton rat–Sigmodon hispidus

meadow vole–Microtus pennsylvanicus

prairie vole–M. ochrogaster

muskrat–Ondatra zibethicus

southern bog lemming–Synaptomys cooperi

coyote–Canis latrans

timber wolf–Canis lupus

kit fox–Vulpes macrotis

giant short-faced bear–Arctodus simus

badger–Taxidea taxus

bobcat–Lynx rufus

Columbian mammoth–Mammuthus colombi

horse–Equus ?

half-ass–Equus ?

flat-headed peccary–Platygonnus compressus

yesterday’s camel–Camelops hesternus

llama–Hemiauchenia sp.

extinct pronghorn–Capromeryx sp.

pronghorn–Antilocapra Americana

upland bison–Bison antiquus

whitetail or mule deer–Odocoileus sp.

Reference:

Johnson, Eileen

Lubbock Lake: Late Quaternary Studies on the Southern High Plains

Texas A&M University Press 1987

 

 

 

Advertisement

Tags: climate on the southern high plains during the late Pleistocene, clovis indians butchered giant short-faced bear and pampathere, gray-breasted crake, Lubbock Lake, megafaunal meat processing station