Between 1968 and 1984, a 7272-yr oak chronology was constructed in Belfast, Northern Ireland, in order to provide a local calibration of the radiocarbon timescale. This single-minded exercise in chronology construction provided an exciting occupation for a group of researchers that can be likened to a race in which there was no guarantee of a finish. The existence of a parallel dendrochronological enterprise in Germany added both competition and the possibility of independent replication. The initial completion of both chronologies by 1984, and respective calibrations by 1986, left an important legacy of 2 absolutely dated tree-ring chronologies for multifarious research purposes.

In this paper, we present an overview of radiocarbon dating contributions from Groningen, concerning 9 sites from around the Mediterranean region: Israel, Sinai (Egypt), Jordan, Spain, Tunisia, and Italy. Full date lists of the 9 sites are presented. Our 14C dates are discussed in terms of present actual chronological debates. We show that all our 14C dates coherently support a "high chronology" for the Iron Age in each respective area of the Mediterranean region.

Sixty years ago, the advent of radiocarbon dating rewrote archaeological chronologies around the world. Forty years ago, the advent of calibration signaled the death knell of the diffusionism that had been the mainstay of archaeological thought for a century. Since then, the revolution has continued, as the extent of calibration has been extended ever further back and as the range of material that can be dated has been expanded. Now a new revolution beckons, one that could allow archaeology to engage in historical debate and usher in an entirely new kind of (pre)history. This paper focuses on more than a decade of experience in utilizing Bayesian approaches routinely for the interpretation of 14C dates in English archaeology, discussing both the practicalities of implementing these methods and their potential for changing archaeological thinking.

W F Libby's new dating method from the 1940s, based on experience in physics and chemistry, opened possibilities to check and revise chronologies built on other principles than radioactive decay. Libby's method initially implied collaboration with archaeologists to demonstrate that it worked but also with physicists to improve the technique to measure low Beta activities. Chemists, geophysicists, botanists, physiologists, statisticians, and other researchers have contributed to a prosperous interdisciplinary development. Some pitfalls were not recognized from the beginning, although issues such as contamination problems were foreseen by Libby. Pretreatment of samples was discussed very early by de Vries and collaborators, among others. This subject has not yet been abandoned. Closely related to pretreatment is the choice of fraction to be dated and chemicals to be used, especially for accelerator mass spectrometry (AMS) measurements. Calibration against tree rings and comparison with dates obtained using other methods as well as intercomparison projects are partly history but still very actual. The impact by man and climate is also studied since the early days of the method. Also, the carbon cycle has been of great interest. The tools for measurements and statistical analysis have been improved during these first 3 or 4 decades, allowing interpretations not possible earlier. 13C determinations are mostly very important and useful, but sometimes they have been misleading in discussions of the origin of carbon, especially for human tissues--the metabolism was not yet fully understood. The history and development of the method can only be illustrated by selected examples in a survey like this.

This paper presents radiocarbon results from modern South Pacific corals from the Marquesas Islands, Vanuatu, Papua New Guinea (PNG), and Easter Island. All of the measurements are from pre-bomb Porites corals that lived during the 1940s and 1950s. The data reflect subannual to multiannual surface ocean 14C variability and allow for precise, unambiguous reservoir age determinations. The results are compared with published values from other coral records throughout the South Pacific, with striking consistency. By comparisons with other published values, we identify 3 South Pacific regions with uniform pre-bomb reservoir ages (1945 to 1955). These are 1) the Central Equatorial South Pacific (361.6 +/- 8.2 14C yr, 2 sigma); 2) the Western Equatorial South Pacific (322.1 +/- 8.6 14C yr, 2 sigma); and 3) the subtropical Pacific (266.8 +/- 13.8 14C yr, 2 sigma). The question of how much, and how fast, South Pacific reservoir ages might have varied in the past is addressed by examining a published record from a Pleistocene coral from Vanuatu that lived over a 700-yr period during the Younger Dryas. The average reservoir age at that time was larger than today, by ~150 yr, and exhibited reservoir age variability on a decadal timescale not seen in modern times. Measured paleo-reservoir ages increase sharply in this record by as many as 300 14C yr in 3 decades. These increases are punctuated by smaller reservoir age decreases, on the order of 150 yr. This reservoir age variability provides a rare picture of active ocean ventilation and ocean-atmosphere exchange at the close of the Pleistocene.

We review developments in radiocarbon measuring techniques from the Libby counter through proportional gas counters and liquid scintillation spectrometers to the more recent developments of accelerator mass spectrometry (AMS), followed by a coupling of gas chromatography with AMS for compound-specific 14C analyses. While during the first 60 yr of 14C measurements beta counting, specifically gas counting, was the dominant technique, in the future of 14C science AMS will be the dominant technology.

The field of dendrochronology had a developmental "head start" of at least several decades relative to the inception of radiocarbon dating in the late 1940s, but that evolution was sufficiently advanced so that unique capabilities of tree-ring science could assure success of the 14C enterprise. The Laboratory of Tree-Ring Research (LTRR) at the University of Arizona played a central role in the cross-pollination of these disciplines by providing the first wood samples of exactly known age for the early testing and establishment of the "Curve of Knowns" by Willard Libby. From the 1950s into the early 1980s, LTRR continued to contribute dated wood samples (bristlecone pine and other wood species) to 14C research and development, including the discovery and characterization of de Vries/Suess "wiggles," calibration of the 14C timescale, and a variety of tests to understand the natural variability of 14C and to refine sample treatment for maximum accuracy. The long and varied relationship of LTRR with 14C initiatives has continued with LTRR contributions to high-resolution studies through the 1990s and systematic efforts now underway that may eventually extend the bristlecone pine chronology back beyond its beginning 8836 yr ago as of 2009. This relationship has been mutualistic such that a half-century ago the visibility and stature of LTRR and dendrochronology were also elevated through their association with 14C-allied "hard sciences."

Recent investigations devoted to the Eurasian loess formations have provided an integrated high-resolution climatic sequence well radiocarbon dated between 13.4 and 42.5 kyr BP on charcoal and wood remains. Here, we show that the reproducible climatic signature of this loess sequence can be compared by proxy-correlation with the Greenland ice climatic signals, taking into account the distribution of the aeolian components in both records. This correlation allows situating with precision the series of 14C dates obtained from loess with regard to the Greenland climatic sequence. In this way, comparing the atmospheric loess-derived 14C chronology with the chronologies of the marine sequences becomes possible.

There are 2 fundamental assumptions in radiocarbon dating, which were known early in the method development to be approximations, and which lead directly to the need to calibrate 14C dates: 1. The rate of formation of 14C in the upper atmosphere has been constant over the entire applied 14C dating timescale (approximately the last 65,000 yr). 2. The 14C activity of the atmosphere has been in equilibrium with the biosphere and ocean over the applied timescale.