Field Methods in Archaeology and Paleoanthropology

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Chapter 5

• Field Methods in Archaeology and Paleoanthropology

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Chapter Preview

• How Are the Physical and Cultural Remains of Past
  Humans Investigated?
• Are Human Physical and Cultural Remains Always
  Found Together?
• How Are Archaeological or Fossil Remains Dated?

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Prehistory and History

• The term prehistory is used to refer to the
  period of time before the appearance of written
  records.
• This does not deny the existence of history,
  merely of written history.

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Paleoanthropology

• The study of the physical remains of our
  ancestors and other ancient primates.
• Paleoanthropologists do more than find and
  catalogue old bones.
• Paleoanthropologists recover, describe, and
  organize these remains to see what they can tell
  us about human biological and cultural evolution.

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Recovering Cultural And Biological Remains

• The only way to thoroughly investigate our past
  is to excavate (dig) sites where biological and
  cultural remains are found.

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Recovering Cultural And Biological Remains

• The fundamental premise of excavation is that
  all digging is destructive, even that done by
  experts. The archaeologists primary
  responsibility, therefore, is to record a site
  for posterity as it is dug because there are no
  second chances.
• - Brian Fagan, archaeologist
• What kinds of information can we get from
  recording a site?
• ANSWER Material Culture and Skeletal
  Remains/Fossils

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Material Culture

• The term material culture refers to the durable
  aspects of culture such as tools, structures, and
  art.

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Types of Material Culture

• Artifacts objects which have been modified by
  hominids (stone tools, ceramics, wood tools,
  etc.)
• Manuports natural objects that were carried by
  hominids but not modified
• Ecofacts natural objects found in association
  with hominids (e.g. plant remains, animal
  remains)
• Features large, non-portable modified objects
  found at hominid sites (e.g. hearths, buildings,
  large statues, rock art, etc.)

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Types of Material Culture For Class Discussion

• Is this example of one of the Nazca Lines in
  Peru a feature, artifact, ecofact or manuport?

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Types of Material Culture For Class Discussion

• Are these examples of Maya sculpture features,
  artifacts, ecofacts or manuports?

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Types of Material Culture For Class Discussion

• Look over this list of material objects and
  decide if they are artifacts, manuports,
  ecofacts, or features
• 1. A lucky rabbits foot
• 2. Bones of a dairy cow
• 3. A stepped-pyramid
• 4. A stone tool
• 5. A hearth or ring of stones

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The Nature of Fossils

• The term fossil refers to any mineralized trace
  or impression of an organism that has been
  preserved in earths crust from past geological
  time.

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The Nature of Fossils

• It is also important to understand the kinds of
  factors that led to the placement of the fossil
  within the ground as well as affected its
  preservation
• TAPHONOMY the study of what happens to bones
  and other material remains once they have been
  discarded or the animal has died, and before they
  are excavated.

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Taphonomy

• Cultural Transforms burial, mortuary ritual,
  plowing, looting
• Natural Transforms erosion, weathering,
  scavenging, natural disasters, animal action in
  the soil, climatic conditions

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Natural and Cultural Burial of the Dead

• Entirely preserved fossil skeletons dating before
  the cultural practice of burial about 100,000
  years ago are quite rare.
• The human fossil record from before this period
  consists primarily of fragmentary remains.

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Natural and Cultural Burial of the Dead

• The fossil record for many fossil primates is
  even poorer, because organic materials decay
  rapidly in the tropical forests where they lived.
  
• By contrast, the fossils of our pre-human
  ancestors are generally better preserved because
  of the arid savanna in which they were located.

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Searching For Artifacts And Fossils

• Places containing archaeological remains of
  previous human activity are known as sites.

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Searching For Artifacts And Fossils

• There are many kinds of sites, and sometimes it
  is difficult to define their boundaries, for
  remains may be strewn over large areas. Sites are
  even found underwater.

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Site Identification

• The first task for the archaeologist is actually
  finding sites to investigate.
• Usually archaeologists survey a region in order
  to plot the sites available for excavation. A
  survey can be made from the ground, but more
  territory can be covered using aerial
  photography.
• Innovations such as geographic information
  systems (GIS), remote sensing, and ground
  penetrating radar (GPR) often complement these
  exploration methods.

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Site Identification

• What archaeologists look for
• (1) soil marks or stains that show up on the
  surface of recently plowed fields. These may
  reveal an archaeological site.
• (2) middens or refuse or garbage disposal areas
  in an archaeological site. May appear to be
  large mounds.

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Excavation

• Since excavations are destructive, archaeologists
  must carefully record the location of material
  remains in three-dimensional space.

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Excavation

• To begin, the land is cleared, and the places to
  be excavated are plotted as a grid system a
  system for recording data in three dimensions
  from an archaeological excavation. Usually
  divides a site into squares (1m x 1m).
• Grids are established using a datum point or
  reference point for a grid system.

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Excavation

• Trowels are used to scrape the soil, and screens
  are used to sift all the loose soils so that even
  the smallest artifacts, such as flint chips or
  beads, are recovered.
• Some archaeologists use flotation a technique
  used to recover very tiny objects by immersion of
  soil samples in water to separate heavy from
  light particles.

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Excavation

• If a site is stratified (i.e. contains layers of
  cultural and biological remains), each layer or
  strata is excavated separately.
• Archaeologists can also use stratigraphy to
  relatively date the remains by means of strata.
  Objects in lower strata are older than objects in
  higher strata.

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Example of Stratigraphy
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Stratigraphy Exercise Which material remain is
older?
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Excavation of Fossils

• Both skill and caution are required to remove a
  fossil from its burial place without damage.
• Paleoanthropologists use a combination of tools
  and materials to do this pickaxes, dental tools,
  enamel coating, burlap for bandages, and
  sculpting plaster.

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State of Preservation

• Artifacts made of inorganic materials such as
  stones are preserved better than artifacts made
  of perishable materials (unless there are
  favorable climatic conditions).

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State of Preservation

• Sometimes the impressions of organic objects
  (such as post holes) can provide clues about the
  objects themselves.

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Sorting Out the Evidence

• Excavation records include a scale map of all
  the features, the stratification of each
  excavated square, a description of the exact
  location and depth of every artifact or bone
  unearthed, and photographs and scale drawings of
  the objects.

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Sorting Out the Evidence

• In the lab, artifacts that have been recovered
  from an excavation must be cleaned and catalogued
  before they are ready for analysis.
• From the shapes of the artifacts as well as from
  the traces of manufacture and wear,
  archaeologists can usually determine their
  function.

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Sorting Out the Evidence

• Other kinds of information gathered from fossils
• (1) Endocasts - Casts of the inside of a skull
  which can help determine the size and shape of
  the brain.
• (2) Coprolites - Preserved fecal material
  providing evidence of the diet and health of past
  organisms.

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Sorting Out the Evidence

• Other kinds of information gathered from fossils
• (3) Small fragments of DNA can be amplified or
  copied repeatedly using polymerase chain reaction
  (PCR) technology to provide a sufficient amount
  of material to perform these analyses.

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Bioarchaeology and Forensics

• The term bioarchaeology refers to the
  archaeological study of human remains emphasizing
  the preservation of cultural and social processes
  in the skeleton.
• Examples include forensic anthropology, human
  osteology, and paleopathology.

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Human Osteology

• (1) determine the sex, age (at death), and
  ancestral population of a skeleton from
  morphological features
• (2) determine wear patterns on the bones and
  teeth from repeated activities
• (3) comparison with other skeletons to determine
  species affiliation

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Human Osteology
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Paleopathology

• - Iron deficiency causes anemia porous bones
• - Vitamin D deficiency causes legs to grow bent.
• - Malnutrition or under-nutrition is inferred
  from skeletal measurements.
• - Certain infections leave specific traces in the
  skeleton.
• - Various cancers are identifiable in the
  skeleton.

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Paleopathology
- Trauma in skeletons is clearly evident in bone
fractures, especially when they have not healed
successfully. - The individual workload leaves
traces in the skeleton. - Growth-disrupting and
growth-retarding stresses during childhood will
leave transverse lines of dense bone visible in
radiographs of long bones of the body.
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Case Studies in Paleopathology

Tibias from a 50-60 year old Roman Soldier,
3rd-4th Century, AD
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Case Studies in Paleopathology

Spear injury to right tibia Osteoporosis on both
tibias
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Case Studies in Paleopathology

Patellas of a 40 year old Moche potter (350-600
AD)
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Case Studies in Paleopathology

Both show wear from extended periods of kneeling
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Case Studies in Paleopathology

Female Skull, 500 AD
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Case Studies in Paleopathology

Blunt force trauma to left side of the face
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Case Studies in Paleopathology

Male Skull, Belize, Postclassic Period (1300 AD)
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Case Studies in Paleopathology

Possible anemia or syphilitic infection
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Case Studies in Paleopathology

Yde Girl a bog body from the Netherlands (1st
Century AD)
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Case Studies in Paleopathology

Hair has been cut off Evidence of strangulation
or hanging
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Case Studies in Paleopathology

Skulls with evidence for cranial re-shaping
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Bioarchaeology and Ethics

• As scientists, anthropologists know the
  importance of the information that can be gleaned
  from studies of human skeletons, but as scholars
  subject to ethical principles, they are bound to
  respect the feelings of those who give skeletons
  a deep cultural and spiritual significance.

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Dating the Past

• Two types of dating
• (1) relative dating - designating an event,
  object, or fossil as being older or younger than
  another.
• (2) absolute or chronometric dating provides
  dates for recovered material based on solar
  years, centuries, or other units of absolute time.

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Relative Dating Techniques

• Seriation a technique for relative dating by
  putting groups of objects into a sequence in
  relation to one another.
• Stratigraphy a technique for relative dating
  based on organizing remains by means of strata.
  Objects in lower strata are older than objects in
  higher strata.

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Relative Dating Techniques

• Palynology a method of relative dating based
  on changes in fossil pollen over time.

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Absolute Dating Techniques

• Radiocarbon dating a technique of dating based
  on measuring the amount of radioactive carbon
  (14C ) left in organic materials found in
  archaeological sites.
• Dendrochronology a method of dating based on
  the number of rings of growth found in a tree
  trunk.

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Absolute Dating Techniques

• Potassium-argon dating a method of absolute
  dating based on measuring the amount of
  radioactive potassium left in a layer of volcanic
  rock.

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Absolute Dating Techniques

• Electron spin resonance measures the number of
  trapped electrons in bone
• Thermo-luminescence measures the amount of
  light emitted from a specimen when heated to high
  temperatures.

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Chance and the Study of the Past

• The archaeological and fossil records are
  imperfect, partial, and non-representative.
• Chance circumstances of preservation and
  discovery have determined what has survived the
  ravages of time to be excavated by
  archaeologists.