Archaeology is the study of the peoples of the past and that past usually is buried in the ground. Some of the most important information comes from the dirt in which archaeologists excavate.

Geology is a science that deals with the history of the earth and its life especially as it is recorded in rocks and sediments. Sediments are a collection of mineral or rock particles that have been weathered or eroded from their primary source and redeposited elsewhere by water, wind, or glaciers. Sediments are deposited in a variety of ways, including wind (aeolian) and water (fluvial for streams; lacustrine for lakes, ponds, and marshes).

Soils are different from sediments. They are not deposited but rather develop in place in sediments already deposited. Soils are made of minerals and organic materials, such as plant remains, that occur naturally on the land surface of the earth. A buried soil (paleosoil) is a fossil soil that while still forming was covered by new sediments so that it stopped formation. Frozen in time, a buried soil can provide information about the climate and environment at the time in which it was forming. Soils found in the archaeological record suggest a stable environment.

Layers of sediments and their soils form a stratigraphy. Providing that the layers are undisturbed, the oldest layers are on the bottom and the younger or most recent are at the top. Artifacts found at the bottom should be older than those on top.

At the Landmark, a water source for peoples on the Southern High Plains for at least the past 12,000 years, understanding the nature of water and how it affects sediments, and thus the stratigraphy, is important to understanding the archaeological record. Hydrology is the study of water including its properties, distribution, and circulation of water on the surface of the land, in the soil and underlying rocks, and in the atmosphere.

A geologic history is represented at the Landmark. The different sediments and buired soils indicate the what the environment was like during different time periods.

Stratigraphy of Lubbock Lake Landmark

Soil Profile	Cultural Period	Sediment Type	Artifacts	Yellowhouse Draw Environment
	Historic 1650 AD - Present	Stratum 5 Rooted soils Sand/gravel	Bones: modern bison and horse, small animals. Square nails, hole-in-cap cans, beads, glass, metal objects	Non-depositional Slope was, valley erosion Windblown sand
	Protohistoric 1500- 1650 AD Ceramic 2,000- 500 BP	Stratum 4 Windblown sand	Bones: modern bison, small animals. Arrow points, pottery, stone and bone tools.	Climate similar to today
	Archaic 8,500- 2,000 BP	Stratum 4 Windblown sand Organic, rich clays	Bones: modern bison, small animals. Spear points, stone and bone tools, ovens for baking desert plants.	Windblown deposits Very dry climate Spring-fed marsh
		Stratum 3 Windblown sand Calcium carbonate (lime)	Bones: ancient bison, small animals. Spear points, atlatl hooks, stone and bone tools.	Windblown deposits Hotter and drier climate than today Alkaline lake
	Firstview Plainview Folsom 10,800-8,600 BP	Stratum 2 Marsh soil	Bones: ancient bison, small animals. Spear points, stone and bone tools.	Spring-fed marsh Lush grasslands Water ponded in floor of draw Lake and marshland (diatomic)
	Clovis 11,500-11,000 BP	Stratum 1 Organic sand/gravel	Bones: stout-legged horse, mammoth, ancient bison, giant short-faced bear, camel, giant armadillo. Spear points, stone and bone tools.	Meandering stream Small groves of trees along waterway Lush grasslands Wetter and cooler climate than today

In some places you can clearly see stratigraphic layers in the earth, such as this site on the western edge of the Llano Estacado near San Jon, New Mexico.

Learn more about the environmental history of the Llano Estacado by visiting these pages:

Paleoindian Period 11,500-8,500 B.P.
Archaic Period 8,500-2,500 B.P.
Ceramic Period 2,500-50 B.P.
Protohistoric Period 500-300 B.P.
Historic Period 300 B.P. - Present