Waves from western Nevada’s Pleistocene Lake Lahontan carved numerous shelters and caves from volcanic bedrock enclosing this immense lake’s multiple basins. In central and eastern Nevada, solution caves formed within limestone bedrock, and lava tubes occur in northern portions of the state. Caves are important sources of archaeological information because they played an essential role in Indian lifeways.
Prehistoric Indians traveled throughout their territory and used specialized toolkits to procure seasonally available plants and game. Caves were commonly utilized as off-season storerooms for basketry, nets, traps, decoys, weapons, and food. Normally perishable objects are preserved in Nevada caves because of the caves’ low microbial activity and consistent aridity.
These sites were also occasionally used for ceremonies, including burials, and for shelter during weather extremes. Only rarely did people live in caves for extended periods of time.
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All Nevadans have lost a great deal of information about the
State’s prehistory to vandals or “pothunters” digging for artifacts in caves. It
is illegal to disturb an archaeological site on public lands without proper
permits. Archaeological site protection began with the 1906 Antiquities Act, but
enforcement was lax, until passage of the Archaeological Resources Protection
Act of 1979. State and other laws protect archaeological sites on tribal,
federal, state lands and, if Native American burials are present, private
property. Successful federal and state prosecution of pothunters has resulted in
fines, prison sentences, and confiscation of tools and vehicles used to commit
the crime. Nowadays, amateur archaeological organizations assist archaeologists in their research. These groups replace some of the popular, but illegal, “arrowhead hunting” of years past. It is also important to understand that small and seemingly unimportant clues are all considered in an archaeologist’s analysis of a find. Loss of an artifact’s context is as serious as loss of the artifact itself. |
This diorama portrays a cross section of the sediments
in a typical wave cut cave used as a seasonal cache site
and shelter from severe weather.
Caves are filled with deposits of fine and coarse grain sediments, and rocks. Layers of fill encasing artifacts and features provide clues to past environmental conditions and age of deposits. Pleistocene Lake Lahontan left behind sediments at the bottom of many of western Nevada’s wave cut caves. Lake algae formed tufa layers atop sediments or bedrock in relatively shallow waters. Waves breaking at the cave mouth left behind rounded and smoothed gravel and coarse sands.
Lake sediments usually grade to fine grained sediments comprising the bulk of a cave’s fill. The silt and fine sand fractions originate from dry lakebeds below the cave and are deposited by wind or by water. Wind borne or aeolian sediments reflect drier climates, while waterborne sediments reflect runoff from the surrounding hillside and wetter weather episodes. Interspersed within the silt and sand strata are layers of volcanic ash and angular rocks dislodged from the walls and ceiling by freeze-thaw cycles or earthquakes.
An artifact’s exact location within a site is extremely important in reconstructing past cultures. Cave fill containing artifacts is arranged in distinctive layers or strata, which are collectively referred to as the site’s stratigraphy. The strata are arranged in chronological order with the older undisturbed layers overlain by successively younger strata.
Archaeologists interpret stratigraphy by examining relationships among
artifacts, sediments, and cultural features. Strata differ in composition
because they were deposited under different environmental and cultural
conditions. These layers also contain plant parts and seeds, bones, volcanic
ash, and other evidence of ancient climate, vegetation, and the nature and age
of site use. For example, Mount Mazama erupted about 7,000 years ago to form Oregon’s Crater Lake, and volcanic ash from its multiple eruptions blanketed the Columbia Plateau and much of the northern Great Basin. This ash and ash from regional volcanoes serve as convenient time markers.
Archaeologists assemble information from many studies to provide
their view of ancient Indian life. Each specialist in an archaeological
investigation asks questions they hope to answer by project’s end.
Stone and bone tools, basketry, pottery, and ornaments are obvious information
sources. Artifact styles can be traced to other sites and regions. Residues on
artifacts provide pollen and protein reflecting past diets or prey. Basketry and
wood can be radiocarbon dated. Obsidian used for tools can be chemically traced
to its source, and a relative age determined through hydration dating.
Archaeologists reconstruct prehistoric diets by analyzing plant parts, seeds,
and animal bones from the deposit. Fossil pollen, volcanic ash, packrat nests,
and sediments provide valuable environmental and chronological information.
Research results are presented in reports, museum exhibits, and other public
presentations. The artifacts and samples of other site materials are stored at
museums or universities for future archaeologists to study with newer methods or
different hypotheses.
