Time Travelers Ch 6-10

Front 1

A date expressed as specific units of scientific measurement, such as days, years, centuries, or millennia; absolute determinations attempt-ing to pinpoint a discrete, known interval in time.

Back 1

absolute date

Front 2

Dates expressed relative to one another ( for instance, earlier, later, more recent) instead of in absolute terms.

Back 2

relative dates

Front 3

The idea that strata containing similar fossil assem-blages are of similar age. This concept enables archaeologists to characterize and date strata within sites using distinctive artifact forms that research shows to be diagnostic of a particular period of time.

Back 3

index fossil concept

Front 4

The keys to relative dating are ___ and _____

Back 4

( 1) the law of superposi-tion introduced in Chapter 5 and ( 2) the index fossil concept.

Front 5

Developed in the early nineteenth century, the index fossil concept is often attributed to British geologist ________

Back 5

William “ Strata” Smith
( 1769– 1839)

Front 6

Th e index fossil concept was introduced to archae-ology by Swedish archaeologist______

Back 6

Oscar Montelius
(1843– 1921).

Front 7

Similar to index fossils in geology; artifact forms that research shows to be diagnostic of a particular period of time are called ___________

Back 7

time-markers

Front 8

The ______permitted archaeologists to produce a chronology of cultural change at a particular site, and the______concept allowed them to date sites relative to one another.

Back 8

law of superposition

index fossil

Front 9

First developed by Euro-pean archaeologists in the late nineteenth century, the ______ technique was introduced to the New World by Alfred Kroeber ( 1876– 1960).

Back 9

seriation

Front 10

The ______ concept relied primarily on the presence or absence of distinctive kinds of artifacts.

Back 10

index fossil

Front 11

Seriation refined the index fossil concept by using changes in the ____ ____ or styles to date sites relative to one another

Back 11

frequencies of artifacts

Front 12

A relative dating method that orders artifacts based on the assumption that one cultural style slowly replaces an earlier style over time

Back 12

seriation

Front 13

With a______, sites can be dated based on their frequency of several artifact
( for instance, ceramic) styles.

Back 13

master seriation diagram

Front 14

First developed by European archaeologists in the late nineteenth century, the ______technique was introduced to the New World by Alfred Kroeber ( 1876– 1960).

Back 14

seriation

Front 15

The shape ofpopularity curves, which archaeologist _______ termed “ battleship-shaped curves” because they often look like a battle-ship’s silhouette from above, is the basis for seriation. By arranging the proportions of temporal types into lozenge-shaped curves, one can determine a relative chronological sequence.

Back 15

James Ford ( 1911– 1968)

Front 16

______ still cannot tell us how old a site or stratum is, only whether it is older or younger than another.

Back 16

seriation

Front 17

____ is The use of annual growth rings in trees to assign calendar ages to ancient wood samples.

Back 17

tree-ring dating
( dendrochronology)

Front 18

dendrochronology, was developed by_____

Back 18

Andrew E. Douglass
( 1867– 1962),

Front 19

The light rings are a year’s _____growth, and the dark rings are that year’s late ______growth

Back 19

spring/ summer
summer/ fall

Front 20

The most commonly used trees for dendochronology are___,___,___,___, and ___

Back 20

piñon pine, ponderosa pine, Douglas fir, juniper, and white fir.

Front 21

In 1949, physical chemist Willard F. Libby ( 1908– 1980) announced to the world that he had discovered a revo-lutionary new dating technique: ____ ____

Back 21

radiocarbon dating.

Front 22

only one 14C atom exists for every_____ atoms of 12C in living material.

Back 22

trillion

Front 23

___is the emission of a negatively charged electron

Back 23

beta emission

Front 24

All r____ _____ are unstable and break down, or “ decay,” over time. 14C decays through beta emissions back into ___.

Back 24

adioactive isotopes
14N

Front 25

as long as an organism is alive, the amount of 14C in it remains in ______ with the atmosphere. But once the organism dies, it ceases to take in 14C, and hence the amount of 14C in its body _____ through decay.

Back 25

equilibrium
decreases

Front 26

Libby calculated that after _____ years, half of the 14C available in a sample will have converted to 14N; this is termed the__ ___ ___of 14C.

Back 26

5568
Libby half- life

Front 27

We have since learned that the actual half- life of 14C is ____ years— the Cambridge half- life.

Back 27

5730

Front 28

To convert a date using the Libby half- life to one using the Cambridge half- life, simply multiply the Libby date by_____

Back 28

1.03

Front 29

Radiocarbon dating is good only for organic remains that are younger than about ______years.

Back 29

45,000

Front 30

The time required for half of the carbon- 14 available in an organic sample to decay; originally set at 5568 years, it was later changed to 5730 years.

Back 30

half-life

Front 31

The first photosynthetic pathway converts atmospheric carbon dioxide into a compound with__ ___atoms

Back 31

three carbon

Front 32

This C3 pathway is characteristic of __,___,___,__, and ___

Back 32

sugar beets, radishes, peas, wheat, and many hardwood trees.

Front 33

The second photosynthetic pathway converts car-bon dioxide into a complex compound with ____atoms

Back 33

four carbon

Front 34

This C4 pathway typifies plants from arid and semiarid regions, including __,__,___,__, and ___

Back 34

maize, sorghum, millet, yucca, and prickly pear.

Front 35

A third, the CAM pathway (__ __ ___), is found in ____

Back 35

( crassulacean acid metabolism”)

succulents, such as cactus.

Front 36

Th e importance of these diff erent photosynthetic pathways is that C4 plants end up taking in ____ 14C relative to the other isotopes of carbon than do C3 and CAM plants.

Back 36

more

Front 37

Libby uses the photosynthetic process of ____ plants as the standard. This can create problems.

Back 37

C3

Front 38

radiocarbon labs can correct this problem by measuring the ratio of ___ to ____ and using that value to normalize the resulting date if the material dated is from a C4 plant.

Back 38

13C to 12C

Front 39

_____are the specific chemical process through which plants metabolize carbon. The three major pathways discriminate against carbon- 13 in different ways; therefore, similarly aged plants that use different pathways can produce different radiocarbon ages.

Back 39

photosynthetic pathways

Front 40

___ is when organisms take in carbon from a source that is depleted of or enriched in carbon- 14 relative to the atmosphere; such samples may return ages that are considerably older or younger than they actually are.

Back 40

reservoir effect

Front 41

Southern hemi-sphere radiocarbon dates are ___to____years too old compared with northern hemisphere dates

Back 41

24 to 40

Front 42

____ are fluctuations in the calibration curve produced by variations in the atmosphere’s carbon- 14 content; these can cause radiocarbon dates to calibrate to more than one calendar age.

Back 42

de Vries effects

Front 43

____is a method of radiocarbon dating that counts the proportion of carbon isotopes directly
( rather than using the indi-rect Geiger counter method), thereby dramatically reducing the quantity of datable material required.

Back 43

accelerator mass spectrometry or AMS

Front 44

AMS cannot reliably date anything that is older than about_____ years.

Back 44

45,000

Front 45

____is a device to measure the amount of gamma radiation emitted by sediments. Often a short length of pure copper tubing filled with ___ ___, it is normally buried in a stratum for a year to record the annual dose of radiation.

Back 45

dosimeter
calcium sulfate

Front 46

__ ___ __ are forms of dating that rely upon the fact that electrons become trapped in minerals’ crystal lattices as a function of background radiation.

Back 46

Trapped Charge Dating

Front 47

In Trapped Charge Dating, The age of the specimen is the total radiation received divided by the ___ ___ _ ___

Back 47

annual dose of radiation.

Front 48

Th ere are three types of trapped charge dating ___ ____ ____

Back 48

thermoluminescence, optically stimulated luminescence, and electron spin resonance

Front 49

background gamma radiation is generated primarily by __ ___ and ____

Back 49

uranium, thorium, and a radioactive isotope of potassium

Front 50

In trapped charge dating the important thing to know is that electrons that are moved out of their orbits ( that is, trapped) by background radiation are returned to their orbits by sufficient heat
( ____) or by exposure to even a few minutes of

Back 50

500° centigrade

Front 51

So, strictly speaking,__ __ __ identifies the last time a specimen had its electron traps emptied.

Back 51

trapped charge dating

Front 52

______ A hominin who lived in Europe and the Near East about 300,000 to 30,000 years ago;

Back 52

C. Neanderthals
( or Neandertals)
biological anthropologists debate whether Neanderthals were in the direct evolutionary line leading to Homo sapiens.

Front 53

______ measures the total radiation dose by heating a specimen rapidly to 500° centigrade. Trapped electrons in quartz and feldspar crystals slip free and move back to their orbits. When they do, they release energy in the form of___The lab measures the amount of light released as the specimen is heated; this gives us the needed measure of the__ ___ ___

Back 53

Thermoluminescence ( TL)
light.
total radiation dose.

Front 54

Archaeologists have used TL to date _____.

Back 54

ceramics

Front 55

OSL therefore dates the time when the sands were ____. Although OSL can be used on a variety of sediments, ______sands are the best because they are more likely to have been sufficiently bleached by sunlight ( and thus have their clocks reset) than alluvial ( water- transported) sands.

Back 55

buried
eolian ( windblown)

Front 56

electron spin resonance ( ESR), whose primary archaeological application is the dating of__ __.

Back 56

tooth enamel

Front 57

Ninety-six percent of tooth enamel consists of the mineral ____ which contains no trapped charges when formed. Once the tooth is deposited in the ground, however, it accumulates charges from background radiation.

Back 57

hydroxyapatite,

Front 58

Trapped charge dating techniques can date objects that are beyond the range of radiocarbon dating. But we must remember that what we are dating is __ __ __ __ ___ __ __by light in the case of ___ and by heat in the case of ___ ( neither seems to aff ect ESR measurements). Like radiocarbon dating, these techniques date accurately to a range of years, not a single year.

Back 58

the last time that the clock was reset
OSL
TL

Front 59

_____cannot be used on rock that is less than 200,000 years old.

Back 59

Radiometric dating techniques

Front 60

____ is a trapped charge technique used to date tooth enamel and burned stone tools; it can date teeth that are beyond the range of radiocarbon dating.

Back 60

electron spin resonance

Front 61

_____ is a high- precision method for estimating the relative quantities of argon- 39 and argon- 40 gas; used to date volcanic ashes that are between 500,000 and several million years old.

Back 61

argon- argon dating

Front 62

In __________the more 40Ar in a sample relative to 40K, the older that sample is.

Back 62

potassium-argon dating

Front 63

Used to date wood as carbon, roof beams, and firewood

Back 63

Dendochrinology

Front 64

back to about 2000 years in the American Southwest Only useful on particular species of trees. Sequence cannot be extended beyond the region it was developed in.

Back 64

Dendochrinology

Front 65

Can be used to date any organic material, carbon the most common

Back 65

Carbon 14

Front 66

Requires calibration; calibration curve reliable to only about 11,000 years. Accelerator mass spectrometry permits dating of minute samples.

Back 66

Carbon 14

Front 67

Accurate to 45,000 bp

Back 67

Carbon 14

Front 68

Used to date ceramics and burned stone back to 300,000yrs

Back 68

Thermoluminescence

Front 69

300,000 years Dates the last time an object was heated to 500° centigrade.

Back 69

Thermoluminescence

Front 70

Used to date Quartz, feldspars in eolian sands Unknown, but perhaps back to 300,000 years

Back 70

Optically stimulated luminescence

Front 71

Dates the last time sand was exposed to sunlight suffi cient to empty the electron traps. Samples must avoid sunlight; lab must date individual grains.

Back 71

Optically stimulated luminescence

Front 72

Used to date Tooth enamel, burned stone tools, corals, shells 10,000 to 300,000 or more years

Back 72

Electronic spin resonance

Front 73

Dates when a tooth was buried. Electron traps reset by exposure to electromag-netic radiation in the lab.

Back 73

Electronic spin resonance

Front 74

Used to date Volcanic ash 200,000 to several million years

Back 74

Argon-argon

Front 75

Dates the eruption that produced the ash. Needs small sample.

Back 75

Argon-argon

Front 76

A potential problem with radiocarbon ( or tree- ring) dat-ing in which old wood has been scavenged and reused in a later archaeologi-cal site; the resulting date is not a true age of the associated human activity.

Back 76

old wood problem

Front 77

Dates in historical archaeology are generally of two types: They either define a _____ __ ___( the site cannot be any older than a particular year) or they estimate a __ __ ___ ( the site’s “ aver-age” age).

Back 77

temporal cutoff point
central temporal tendency

Front 78

The systematic arrangement of material culture into types.

Back 78

typology

Front 79

____ is a class of archaeological artifacts defined by a consistent clustering of attributes

Back 79

type

Front 80

____ are The delineation of patterns in material culture through time and over space. These patterns are what the archaeologist will eventually try to explain or account for.

Back 80

space- time systematics

Front 81

____ is A descriptive and abstract grouping of individual arti-facts whose focus is on overall similarity rather than function or chronological significance.

Back 81

morphological type

Front 82

Morphological types are purely _____

Back 82

descriptive.

Front 83

____ ____ are morphologi-cal types that have specific chronological meaning for a particular region. In other words, they are __ __.

Back 83

Temporal types
time-markers

Front 84

___ ____ reflect how objects were used in the past. They can crosscut morphological types.

Back 84

Functional types

Front 85

___ ____can also crosscut temporal types.

Back 85

Functional types

Front 86

A good typology possesses two crucial characteristics:

Back 86

1. Regardless of its fi nal purpose, a typology must mini-mize the diff erences within each created type and max-imize the diff erences between types. If a lot of overlap or ambiguity occurs in the types, then they cannot reveal any signifi cant or meaningful patterning. 2. Th e typology must be objective and explicit. Th is means that the result should be replicable by any trained observer. If it is not replicable, then your methods cannot be duplicated ( and your work is therefore not scientific).

Front 87

__ ___ is A morphological type that has temporal significance; also known as a time- marker or index fossil.

Back 87

temporal type

Front 88

__ ___ is A class of artifacts that performed the same function; these may or may not be temporal and/ or morphological types.

Back 88

functional type

Front 89

___ is An individual characteristic that distinguishes one artifact from another on the basis of its size, surface texture, form, material, method of manufacture, or design pattern.

Back 89

attribute

Front 90

____ is A culture from the Middle Paleolithic (“ Middle Old Stone Age”) period that appeared throughout Europe after 250,000 and before 30,000 years ago.

Back 90

Mousterian

Front 91

______ artifacts are frequently associated with Neanderthal human remains.

Back 91

Mousterian

Front 92

Consider the first characteristic: _____the differences within each type and _____ the differences between types.

Back 92

minimize
maximize