Radiocarbon dating its scope and limitations
Long does not deal with the issue of the development of agriculture in Mesoamerica, where the plants which were domesticated were pumpkins, peppers, and beaus." It is true that the domestication of plants in Mexico occurred at a relatively later date and played a very minor role for a long time. only 10% of the diet came from domesticated plants.Nonetheless the Neolithic revolution in America seems to have developed quite independently of Old World influence.Long's citation of a remark by the Egyptologist, T.Save-Soderbergh, might lead readers to believe that scholars simply use radiocarbon dates only when these dates suit their preconceived theories.It should be noted that there is an apparent discrepancy between the Egyptian data and radiocarbon readings as one goes back in time before 2000 B. Whereas Egyptian records date the beginning of the 1st Dynasty c. C.; radiocarbon dates for this dynasty are some four to five hundred years younger.On the basis of the new information from dendrochronology, i.e., the analysis of bristlecone pine tree-rings, it is possible to establish correction factors which succeed in achieving an excellent correlation of radiocarbon dates and Egyptian data. the calibrated carbon-14 dates for Egypt agree far better with the historical chronology than the uncalibrated ones did." Noting that more than 100 rings max' exist within an inch of the Pinus aristata, the long-lived Bristlecone pine, Long wonders "how very much accuracy is obtainable." He further remarks, "By some magical process, known only to a few, dendrochronologists claim to be able to join tree-rings from different trees for a stage chronology of growth in time." His main contention is that the Suess calibration curve derived from the California trees has no validity for European dates inasmuch as trees of similar longevity have not beet) discovered in Europe.
The earliest Neolithic site seems to he Jericho just north of the Dead Sea, a site dated to 7000 B. But neither Gorman or Solheim make any claim that Neolithic techniques were diffused from Thailand throughout the world; they simply claim that the Neolithic revolution occurred very early in Thailand and then influenced developments in China.To be sure, this danger exists and some scholars may misuse radiocarbon readings.Nonetheless, there is an impressive correlation of radiocarbon dates with the absolute chronology of the Egyptians, which was meticulously maintained.Nor is the correlation of patterns of signatures, i.e., sequenial arrangements of wide and narrow rings forming recognizable patterns, from different trees to obtain a series of overlapping plottings a mysterious process.Tests of nuclear weapons have shown that atmospheric mixing is rapid and that irregularities in composition are smoothed out after a few years.