Project IR Butler 2019-20 - Get one IR Question EverydayQuestion # 04, Date : 04-Oct-2019
This post is a part of Project IR Butler 2019-20.
Click here for Details Techniques: Island Museum analyzes historical artifacts using one or more techniques described below—all but one of which is performed by an outside laboratory—to obtain specific information about an object’s creation. For each type of material listed, the museum uses only the technique described:
Animal teeth or bones: The museum performs isotope ratio mass spectrometry (IRMS) in-house to determine the ratios of chemical elements present, yielding clues as to the animal’s diet and the minerals in its water supply.
Metallic ores or alloys: Inductively coupled plasma mass spectrometry (ICP-MS) is used to determine the ratios of traces of metallic isotopes present, which differ according to where the sample was obtained.
Plant matter: While they are living, plants absorb carbon-14, which decays at a predictable rate after death; thus radiocarbon dating is used to estimate a plant’s date of death.
Fired-clay objects: Thermoluminescence (TL) dating is used to provide an estimate of the time since clay was fired to create the object.
Artifacts: Island Museum has acquired a collection of metal, fired clay, stone, bone, and wooden artifacts found on the Kaxna Islands, and presumed to be from the Kaxna Kingdom of 1250–850 BC. Researchers have mapped all the mines, quarries, and sources of clay on Kaxna and know that wooden artifacts of that time were generally created within 2 years after tree harvest. There is, however, considerable uncertainty as to whether these artifacts were actually created on Kaxna.
In analyzing these artifacts, the museum assumes that radiocarbon dating is accurate to approximately ±200 years and TL dating is accurate to approximately ±100years.
Budget:For outside laboratory tests, the museum’s first-year budget for the Kaxna collection allows unlimited IRMS testing, and a total of $7,000—equal to the cost of 4 TL tests plus 15 radiocarbon tests, or the cost of 40 ICP-MS tests—for all other tests. For each technique applied by an outside lab, the museum is charged a fixed price per artifact.
Question #1Which one of the following pieces of information would, on its own, provide the strongest evidence that the given artifact was actually produced on Kaxna? A. A radiocarbon date of 1050 BC for a wooden bowl
B. IRMS analysis of a necklace made from animal bones and teeth
C. A TL date for a fired-clay brick that places it definitively in the period of the Kaxna Kingdom
D. ICP-MS analysis of a metal tool that reveals element ratios unique to a mine on Kaxna
E. Determination that a stone statue was found near a quarry known to produce stone statues during the Kaxna Kingdom
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Official Explanation Q #1 OA: D
Options A and C provide information about the date of an artifact’s creation, but not about the location where the artifact was made. A radiocarbon date of 1050 BC for a wooden bowl (option A) implies that the tree from which the bowl was made was harvested during the years 1250–850 BC, the time period of the Kaxna Kingdom; but the bowl need not have been produced on Kaxna. Likewise, if TL dating establishes that a fired-clay artifact was produced during that period (option C), it cannot establish the location where it was made. In contrast, option E provides information about location, but since a statue found near a quarry need not have been made at that quarry, the evidence is not very strong.
Options B and D provide information about artifact element ratios. In option B, IRMS analysis of an artifact made of bones and teeth may reveal similarities between the element ratios of the artifact and the element ratios of similar artifacts known to be created on Kaxna, but additional research would be required to determine whether those element ratios were unique to Kaxna. But, in option D, ICP-MS analysis of a metal artifact reveals element ratios known to be unique to a mine on Kaxna, offering far stronger evidence that the artifact was made on Kaxna. Thus, option D offers the strongest evidence among the options listed.
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| Yes | No | Values |
| | Bronze statue of a deer |
| | Fired-clay pot |
| | Wooden statue of a warrior |
| Yes | No | Values |
| ✔ | Bronze statue of a deer |
| ✔ | | Fired-clay pot |
| ✔ | | Wooden statue of a warrior |
| Yes | No | Values |
| | Bone necklace shown by IRMS to have element
ratios characteristic of artifacts known to be from
the Kaxna Kingdom |
| | Fired-clay jug dated to 1050 BC by TL dating |
| | Copper box shown by ICP-MS to have the same
ratio of trace metals found in the copper mines of
Kaxna |
| Yes | No | Values |
| ✔ | Bone necklace shown by IRMS to have element
ratios characteristic of artifacts known to be from
the Kaxna Kingdom |
| ✔ | | Fired-clay jug dated to 1050 BC by TL dating |
| ✔ | Copper box shown by ICP-MS to have the same
ratio of trace metals found in the copper mines of
Kaxna |
| Yes | No | Values |
| | 2 bone implements and 5S fired-clay cups decorated with gold |
| | 7 wooden statues and 20 metal implements |
| | 15 wooden statues decorated with bone |
Question #6Among the Kaxna artifacts is a wooden box containing both a small fired-clay bead and some river sediment containing clay and plant matter. Based on the museum’s assumptions, which one of the following details about the bead can be determined by applying one of the tests in the manner described?A. A range of dates for its manufacture
B. The Kaxna island on which it was made
C. Vegetation patterns near the workshop where it was made
D. A range of dates for its placement in the box
E. The source of clay used to make the bead
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Updated on: 18 Nov 2020, 08:29
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