Lake and loess sediments represent archives that record important information about the iocal, regional and global climate conditions in the past. Lake sediments consist of autochthonous particles formed by biogeochemical processes within the lake and allochthonous particles brought into the lake from the catchment area. After deposition, the stratigraphy of the sediment can be altered by chemical, physical and biological processes. Under favored conditions, the sediment shows individual annual layers (varves), which can be used to date the sediment. Other dating methods are based on radioactive decay (14C, 210Pb) or on time markers such as tephra layers, deposits of natural catastrophes, e.g., floods, or radioactivity, e.g., emissions from a nuclear power plant.

In a recent paper (Hartwig, ms.) I have shown that it is possible to understand and discuss the changing Austausch (i.e., exchange of air parcels between different atmospheric layers) between the stratosphere and troposphere by means of long-term measurement of series of spallation products. It is well known (Friend 1961; Müh et al. 1966; Hartwig et al. 1969) that there is a seasonal pattern in the 7Be concentration of ground-level air with a maximum during May–June. This maximum is caused by enhanced exchange processes between the atmospheric compartments of the stratosphere and troposphere during this interval. Generally, those exchange processes are a consequence of stability and dynamics of the atmospheric compartments, which themselves result from, among other factors, the distribution of the heat sources in those compartments, namely the ground and the ozone layer.

Following the 12th International Radiocarbon Conference in Trondheim, a special calibration issue was published (Stuiver and Kra 1986) carrying a bidecadal calibration curve from 1950 cal ad–2500 cal bc (Stuiver and Pearson 1986; Pearson and Stuiver 1986) that was recommended at the conference (Mook 1986).

Radiocarbon dating is an important tool for reconstructing Late Quaternary paleoenvironmental history of the Antarctic continent. Because of the scarcity of datable material, new suitable substances are welcomed. We present here novel paleoenvironmental records—subfossil stomach oil deposits (mumiyo). This waxy organic material is found in petrel breeding colonies, especially in those of snow petrels, Pagodroma nivea. The substance is formed by accumulation and solidification of stomach oil regurgitated for the purpose of defense. We demonstrate and outline the usefulness and limitations of 14C dating mumiyo for determining dates of local ice retreat, moraines and petrel occupation history.

We examine the pollen analytical and 14C sequences from two Sumatra highland sites, Pea Bullok (2°15'N, 99°02'E) and Danau di-Atas (1°04'S, 100°46'E). The pollen diagrams do not correlate particularly well, possibly because two of the samples from Danau di-Atas analyzed by radioactive decay counting earlier should be infinite. Other complications are differences in the type of site, local topography, pollen sums used and difficulty in distinguishing between pollen taxa from local and regional vegetation. The older material from Pea Bullok was AMS dated.

We have performed a high-precision 14C wiggle-matching study on two oak beams from the “Castle of Amsterdam”. These beams are also dated by dendrochronology. Our two dating methods can only be made consistent using the recommended calibration curve (1986) instead of the revised one (1993).

Sedimentological, mineral magnetic and carbon isotopic studies on cores from Mansar Lake in the Jammu area provide paleomonsoonal history dating back to 580 bc. From ca. 580 bc to ad 300, the region experienced precipitation similar to the present, whereas from ad 300 to 1400, the monsoon was relatively subdued. A small excursion ca. ad 1100 suggests an effect of medieval warming. Studies in the Kumaon region did not provide a proper precipitation record, as anthropogenic activity interfered with sedimentation. Manasbal Lake in Kashmir gave an inversion of 14C chronology due to younger paleosols in the drainage basin. Further, the episodic nature of sedimentation in Manasbal Lake hampered the reconstruction of precipitation history in the area.

The cause of the mid-Holocene elm decline in northwestern Europe and its relation to the contemporaneous transition from Mesolithic to Neolithic economy are still unclear, partly owing to the lack of a precise, calibrated chronology. Matching of a sequence of 14C dates to the calibration curve in combination with accurate 14C dating allows high-precision dating of paleoecological events. We have completed high-resolution dating of a Sphagnum-peat sequence from Ageröds Mosse in southernmost Sweden. The basis for selecting 14C samples was pollen analysis at 1 cm intervals. Nine 14C dates, covering an interval of ca. 500 calendar years around the elm decline, showed that this event occurred in Ageröds Mosse within a few decades ca. 3770 bc.

The Israelite site of Kuntillet Ajrud in northern Sinai contains unique drawings and inscriptions in ancient Hebrew and Phoenician. It is a single-phase site dated archaeologically to ca. 800 bce. We considered this site a good test case for comparing archaeological with 14C datings. The dates are in agreement, confirming that 14C dating is useful in dating Iron-Age II sites.

Samples from Tell es-Sultan, Jericho, were selected for high-precision 14C dating as a contribution toward the establishment of an independent radiocarbon chronology of Near Eastern archaeology. The material derives from archaeological excavations conducted by K. M. Kenyon in the 1950s. We present here the results of 18 samples, associated stratigraphically with the end of the Middle Bronze Age (MBA) at Tell es-Sultan. Six short-lived samples consist of charred cereal grains and 12 multiyear samples are composed of charcoal. The weighted average 14C date of the short-lived grains is 3306 ± 7 bp. The multiyear charcoal yielded, as expected, a somewhat older average: 3370 ± 6 bp. Both dates are more precise than the standard deviation (a) of the calibration curves and the absolute standard of oxalic acid. Calibration of the above Jericho dates is a bit premature, because several groups are currently testing the accuracy of both the 1986 and 1993 calibration curves. Nevertheless, preliminary calibration results are presented for comparison, based on 4 different calibration curves and 3 different computer programs. Wiggles in the calibration curves translate the precise bp dates into rather wide ranges in historical years. The final destruction of MBA Jericho occurred during the late 17th or the 16th century bc. More definite statements about the calibrated ages cannot be made until the accuracy of available calibration curves has been tested. Development of calibration curves for the Eastern Mediterranean region would be important.

In 1968, H. Quitta, J. Herrmann, G. Kohl and P. H. Thong initiated cooperation between the Archaeological Institute in Hanoi and the Radiocarbon Dating Laboratory in Berlin. Since 1969, the Berlin 14C laboratory has measured 215 14C dates from 65 archaeological sites in Vietnam. As a result, important problems in Vietnamese archaeology have been recognized and partially solved with the aid of a secure chronological framework.