Clovis 13,00 calendar years BP-
lasted 3-700 years
archaeologists were convince about people coming to americas when first discovered clovis.
(thought to be) pre-clovis sites:
Calico Hills
late 60's, Yermo- Southern California, many genuine artifacts, purported artifacts found and were estimated to be 200,000 years old.. naturally broken rocks that appear to look like artifacts
lewis leakey- worked on early human origins in africa and north america.. supported that these rock pieces were in fact artifacts- held convention and others decided these were not artifacts> led by C. Vance Haynes (opposition)
Old Crow Basin
1966, yukon territory
tool made from caribou tibia- date on bone apatite at 27,000
many broken mammoth bone "tools" found in riverbed- dates ranging 27,000-50,000+
can be accounted for by natural causes
none come from primary arch. context all have been washed into river basin
re-date tibia tool using collagen fraction, 1350 +/- 150 bp
context is very important > need to be with other artifacts
Pedra Furad
Large rock shelter in northeastern Brazil, 1973
Series of radiocarbon dates to more than 48,000 BP
Great later artifacts found at site (in upper layers)- rich holocene deposits with hearths, rock art, exotic chert
(lower) pleistocene layers have quartzite cobble tools
checked out by paleo-police> cobble tools LOOKED like artifacts but are not
at base of cliff> quartzite at top- its fall explains how they were broken up and appeared to look like artifacts (geofacts)
-issues with use of radio carbon years versus calendar dates- class with use calendar dates`
MONTE VERDE
Dillehay
1980s, southern Chile, ~50 km inland from pacific ocean
water-saturate peat (unusual)
Everything was very well preserved> no doubt that this was manmade
wood, fruit, seeds, leaves, stems, marine algae, animal hide, tar, salt, shell
Two large hearths lined with imported clay
human presence confirmed by undeniable artifacts or human bones
undisturbed stratigraphic context
indisputable radiometric dates
^requirements for pre-clovis acceptance
Meadowcroft Rockshelter
western Pennsylvania, 1970s, 1980s, and 1990s
woodland and archaic occupation
indisputable stone artifacts and hearth in lowest stratum
charcoal dates to before 16,000 cal BP
Debate: 1. dates aren't good enough- potential contamination from flecks of coal, potential contamination from carbon-enriched water 2. response- over 50 dates total- almost all in order, evidence that there is no groundwater contamination> supported by paleo-police
^ has not yet been OFFICIALLY accepted
Topper Site
South Carolina, 2000s
OSL date to 13,500 +/- 1000 in clovis layer - definite clovis occupation
OSL date to 15,200 +/- 1500 at transition to pre-clovis level
good stratigraphy
questionable artifacts
radiometric dating- questionable
debatable
Cactus Hill
Virginia, 2000s
definite clovis occupation, with definite artifacts below
lots of vertical mixing
several dates obtained for the lower level, but only early ones accepted (never a good reason why)
substantial evidence for vertical mixing
debatable
SOLVING THE PROBLEM:
Where did people come from?
When did they get here?
How did they get here?
Why did they come?
Who were they?
The Quaternary Ice Age:
~2-5 million years
pleistocene (2.5 million to 12,000 years ago)
holocene (12,000 years ago to present)
alternating glacial periods (stades) and interglacial periods (interstades)
> glaciers responsible for many of the landforms on earth today
To make a glacier:
1. land
2. precipitation
3. cold summers
Glaciers flow, top moves faster than bottom
create morains> as glacier moves rocks and boulders and earth are push out of the way
Milankovic Cycles:
Explain why we go into and out of the glacial period
~100,000 year cycle of the earth's axis ad orbit
precession: not spinning on perfect line
obliquity/axial tilt: has to do with where the tilt of earths rotation is, different parts of earth get more sun because of earths tilt
eccentricty: controls how far earth is from sun- orbit is not a perfect circle- size and position of ellipse changes (more circular less change with seasons)
Solar Forcing:
Insolation
Albedo effect (reflectivity)
climatic equability- summers and winters are more alike- ice age has warmer winters and colder summers
Glaciers and Sea Levels:
sea levels dropped 120-150 meters below current sea level- exposed a great deal of land such as bering land bridge > appeared 28,000-12,000 cal BP - things have bee going back and forth in both directions- so broad that people would not recognize they were moving to a new continent- did know they were switching hemispheres and doing something unique
Last glacial period: late wisconsin glaciation or late pleistocene; 35,000 to 12,000 cal BP
LGM: last glacial Maximum; 21,000 cal BP
people probably entered new world during last glacial period- while ice age was winding down
was not enough moisture in beringia to create glaciers- so it was easy to cross land bridge> until getting into alaska where they encountered mountains and glaciers
North American Glaciers:
Laurentide Ice Sheet- centered over hudson bay, very large- over 3 km thick> pushed earths crust into softer mantle
Cordilleran Ice Sheet- formed in middle of mountain ranges of n america and actually merged with laurentide
Merged from ~25,000 to 13,500 cal BP
Deglaciation:
Very gradual process
two ice sheets out of phase with each other, impacted each other
West Coast Deglaciation:
Alaska Peinsula: 17,000 cal BP (date of deglaciation though it appears these areas were ever completely glaciated)
Vancouver Island: 16,000 cal BP
Refugia?
Could plants and animals survive in refugia - bear evidence (looks as though bears stuck around)
Ice Margins:
constantly wet
Katabic Winds
Glacial Lakes
Permafrost
Inhospitable- not pleasant place to live
North American Climate:
affected by glaciers
South of Ice Sheets
Polar Jet Stream Split (dried out eastern US when split)
Changing precipitation regimes
ice sheets clocked polar air
average temps: 5-7 celsius cooler than today - mild climates
summers cooler, winters warmer
North American Climate:
Bolling.Allerod Warming event: 15,000 to 12,900 years ago
Youger dryas Cooling even: 12,900 to 11,400 cal BP
glaciers re-advanced, return to full glacial conditions in some areas
global phenomenon, but more sever in some areas than others
beginning of agriculture, other interesting archaeological events
*12,900 years ago- end of clovis people and the time agriculture developed in Middle East
What Caused the Younger Dryas?
1.glacial lake agassiz
catastrophic flooding through St. Lawrence Seaway- flooded into north atlantic in number of days
2.thermohaline circulation - through whole globe into glacial period
warm water rises, cold water sinks
salty water - heavy, fresh water- light
3. Younger dryas impact event or the clovis comet- astroid impacted or nearly impacted on laurentide ice sheet- would not leave behind a crater but did leave behind a layer of unusual materials (including nano-diamonds) underneath "black mat" (heavily organic layer)
connected to megafauna extinctions, end of clovis
more outlandish but has not been disproved
Late Pleistocene Plants and Animals:
equable climates > much wider distribution of species > plants and animals together that would not be today
no modern analogies to this environment
plant or animals distribution is controlled by what it can't handle
Now Extinct: Pleistocene Megafauna:
Animals in North America: columbian mammoths, giant pleistocene bison, sabertooth cat, ground sloth, taper, giant north american beaver, dire wolves, giant short faced bear (very large and quite mean)
Humans at the End of the Ice Age:
homosapiens Out Of africa: ~70,000 years ago
Into:
southern and east Asia: 70,000 to 40,000 years ago
Australia: ~50,000 years ago
Europe: ~ 45,000 to 25,000 years ago (neanderthals still in this area)
Northeast Asia: 39,000 years ago
Getting to the Americas:
possible routes:
1. Bering Land Bridge Route:
via northeast asia, after the LGM along the northwest coast
via northeast asia, before the LGM, either along the coast of inland
2. Other Routes:
South Pacific Island Hopping during the LGM
North Atlantic, skimming ice and land during the LG to reach the mid-Atlantic region
Evidence:
Humans in southern Chile y ~14,500 years ago
Humans probably in western Pennsylvania by ~16000 years ago
Humans staged at various points around the globe, with seafaring technology and a wide variety of tools for acquiring .......
Linguistics:
Joseph Greenberg: Mass Comparison Technique
Three broad language families: Eskimo-aleut (3rd), Na Dene (2nd), and Amerind (1st)
Corresponds to three migrations
Objections to Greenberg's methods:
- mass comparison doesn't work
-words are just one component
-three groups considered inadequate
Nichols: Two Major groupings:
- eastern population, divided ~50,000 years ago
- Western population, linked with other Pacific rim, divided ~24,000 years ago
Dental Evidence:
Christy Turner
working, but not openly, with Greenberg
200,000 teth from 9,000 individuals from various parts of world
identified certain traits statistically spread out within specific populations
incisor shovelling, number of roots or molars, winging of incisors, and other tooth traits
Sinodonty and Sundadanty
Asian and American Sinodots are different
American Sinodonts can be divided into three groups- Amerind, Na-Dene, and Ekimo-Aleut
Linked languages teeth and artifacts over thousands of years (with Greenberg) <suspicious
*language and teeth are really on good sources of research up to a few thousand years ago, and people move around differently than people
Genetics: mtDNA
mtDNA: inherited though mother > no recombination
mutates relatively quickly, compared to ~2 million years for nuclear DNA
Five primary prehistoric haplogroups in the Americas: haplogroups A, B, C D, and X
A through D: also common in asia
X: very rare haplogroup- rare in Native Americans, also found (rarely) in Eastern European populations < assumptions that haplogroup X was in asia and is not extinct there and filtered into the americas and eastern europe
Debate:
Three Migrations:
- migration from siberia ~34000 to 26000 years ago bringing A C and D
- migration from east asia along coast, 15,000 to 12000 years ago with B
- migration from siberia/beringia, 10000 to 7000 years ago, with existing haplogroups
One Migration:
-formed group with all 4 haplogroups while still in asia
-population in mongolia with same four haplogroups- share a common ancestor?
Cranial Evidence:
very small sample- seven skeletons in New World with good dates before 8000 cal BP
Generally point to australia, south Asia
Split somewhere in eastern or central asia
modern "mongoloid" traits could be genetic drift, or could be a later migration, perhaps after 5000 cal bp
Archaeological Evidence:
very little
few sites
needed to be able to come to good conclusions
people lived on coast so much evidence in drowned
still looking for older sites...
Where did they come from?
1. Southeast asia, island hopping to south america
came up because of monte verde and early south american sites since they are older or just as old as north america- were they (south america) there first?
evidence?
reason?
Theory is no longer discusses- veerrrry unlikely
2. European Solutrean connection- technological group in spain and portugal (+ other parts of western europe) ~ 21,000 - 17,000 years ago
argued that there are many technological affinites
mtDNA haplogroup X
Clovis in east older than Clovis in west
"Marine Adaption"
objections: massive time gap
more connections with northeast asia
inadequate and superficial technological similarities
not "marine adaptive," but "using littoral resources"
-northwest asia is still best solution
3. Ice-free corridor hypothesis opened up around same time as clovis- disproved when found out clovis was not first
questioned during the 1990s
rejected as first migration during the 2000s
4. *Coastal Migration Hypothesis
Did they have boats?
early sites along the coast
5. Kelp Highway Hypothesis- migration aided by kelp forests > very difficult to prove
Problems with finding early coastal sites
