Evergreen trees in the tropical rain forest of the Amazonas Basin can produce growth rings which are not necessarily related to annual events. Therefore, estimation of growth rate cannot be done by dendrochronology. This report presents a technique for determining the growth rate of these trees based on radiocarbon measurements of two segments of equal radial distance from the outer part of the tree trunk. The measured 14C activity is compared to local 14C fallout and growth rates are derived from models taking into account bomb 14C effects. Eleven trees from various parts of the Amazon Basin were analyzed. The average growth rates range from ca 5 to > 40 yr per centimeter corresponding to extrapolated ages from ca 60 to > 400 yr.

This paper presents a synthetic approach to 14C dating of calcareous tufa, based on statistical analysis of correlations betwen lithologic type of tufaceous sediment, carbon isotope composition, and apparent age. Experimental data on several profiles from southern Poland and the United Kingdom reveal either constant or systematically changing values of apparent age. Constant value of apparent age in a profile can be attributed to calcareous muds precipitated from stagnant or low-energy water, and to tufas precipitated from turbulent water (oncoids, stromatolites, moss travertines) which are characterized by lack of significant correlation between δ13C and 14C age of tufa carbonate. It was found that the relation between the apparent age of tufaceous sediment and δ13C value of tufa carbonate depends on lithologic type of tufa. Phenomenological equations describing the dependence of apparent age upon δ13C are given, and applied to estimate true ages of tufas from Gliczarów (southern Poland) and Folkestone (United Kingdom).

Traces of uranium and radium within the 14C sample generate radon (Rn) which gets occluded during the benzene synthesis, thus generating false (extra) counts within the 14C counting window. This, if undetected, gives rise to erroneous 14C age determinations. The application of simultaneous α and β liquid scintillation spectrometry will enable a mathematical evaluation of the 14C signal unaffected by α and β particle emissions from radon decay daughters.

Since 1984, a large multi-disciplinary archaeological team, under the direction of the author, has collected artifactual, ecofactual, and radiocarbon samples from a series of Native American sites spanning the past 9600 14C years. Occupied historically by the Chumash Indians, the Santa Barbara coast (Fig 1) has seen dramatic cultural and environmental change during the course of the Holocene. One of the goals of the research is to reconstruct patterns in the evolution of the local coastline, while examining the effects of environmental change on human adaptation along the Santa Barbara coast.

This list contains the results of measurements of 172 radiocarbon samples made between January 1983 and December 1985. An additional 152 samples were measured, but these were submitted without detailed information, such as sample location and sampling depth; therefore, they were excluded from the list.

This list is part of a program of publishing our large backlog of unpublished dates. The dates listed here, from 1974 to 1979, include archaeologic samples from various cultures and countries and geologic samples related to sea-level variations, volcanism, and especially the history of paleolakes in Africa.

The following list reports radiocarbon dates of geologic samples collected from the west, southwest and south coasts of Sri Lanka during August 1985. The tidal range on Sri Lanka coasts is very small, the lowest neap at − 0.48m and highest spring at + 0.52m from msl (data based on the standard point of Colombo, datum level 0.38m below msl).

The Second International Symposium on Archaeology and 14C, September 7–11, 1987, Groningen, The Netherlands was a most successful forum for the exchange of information and ideas among archaeologists and radiocarbon daters. The sincere intent of the organizers to achieve closer understanding and appreciation between the two disciplines was apparent throughout the conference. Indeed, even the conference title was changed from “14C and Archaeology” to “Archaeology and 14C.”