The electron spin resonance (ESR) spectra and the natural and gamma-induced thermoluminescence (TL) glow curves of a series of variably cation-exchanged Fe-Ca-clays prepared from SWy-1 montmorillonite were examined. The ESR signal (g = 2) intensity associated with the surface Fe was found to increase linearly with surface Fe content up to a nominal concentration of 50% exchangeable Fe. At > 50% exchangeable Fe, no appreciable increase in the signal was noted. The TL intensity decreased linearly with increasing surface Fe up to 50% nominal exchangeable Fe. At > 50%, the signal was not appreciably further diminished. The natural TL showed only a high-temperature peak, but irradiation produced an additional low-temperature peak. One month after gamma-irradiation, the integrated TL signal was still 10–100 times higher than that from the non-irradiated material. Thus, (1) surface iron clusters may form above a certain critical Fe concentration; (2) the Fe clusters are probably less effective in quenching TL than are single Fe atoms, implying interaction between surface Fe and the stored energy content of the material; and (3) the electronic energy stored in the material as the result of gamma-irradiation is only slowly dissipated.

The scientific study of Neolithic monuments holds fundamental keys to the analysis of early social complexity. This is often impeded by the challenges involved in understanding their temporality and, particularly, their initial construction dates. This problem is most severe in monuments that were not predominantly used for burial and went on to have long biographies in which activity in later periods obliterated the material record of the earliest phases. That was certainly the case of the Menga dolmen, part of the Antequera World Heritage site (Málaga, Spain), and one of the most remarkable megaliths in Europe, for which, after nearly 200 years of explorations and research, no firm chronology existed. The research presented in this paper shows how this problem was tackled through a multimethod, scientific, and geoarchaeological approach. The analysis of 29 fresh numerical ages, including radiocarbon determinations as well as optically stimulated luminescence, thermoluminescence, and uranium-thorium dates, led to the successful establishment of Menga's construction date and the subsequent contextualization of the monument within the social and cultural background it arose in. Placing the dolmen in the context of its time of “birth” introduces entirely new possibilities for its interpretation, both in terms of local and supralocal social and cultural processes.

Thermoluminescence (TL) studies of insulators, including crystals of minerals such as calcite, quartz or zircon, have resulted in the development of a wider range of applications in the fields of radiation dosimetry and archaeological and geological dating. Most conventional TL measurements are made by recording light emission during heating by means of broad-band optical filters and blue-sensitive photomultiplier tubes. Much more information may be gained by monitoring the details of the emission spectrum during thermoluminescence. TL spectra of minerals exhibit changes as a result of crystal purity, radiation dose, dose rate and thermal history. This paper exemplifies the additional information available as a result of spectral studies, and focuses on investigations undertaken by the University of Sussex TL group. Examples include work on calcite, fluorite, zircon and feldspars.

Loess accumulated on a Bull Lake outwash terrace of Marine Oxygen Isotope Stage 6 (MIS 6) age in southern Jackson Hole, Wyoming. The 9 m section displays eight intervals of loess deposition (Loess 1 to Loess 8, oldest), each followed by soil development. Our age-depth model is constrained by thermoluminescence, meteoric 10Be accumulation in soils, and cosmogenic 10Be surface exposure ages. We use particle size, geochemical, mineral-magnetic, and clay mineralogical data to interpret loess sources and pedogenesis. Deposition of MIS 6 loess was followed by a tripartite soil/thin loess complex (Soils 8, 7, and 6) apparently reflecting the large climatic oscillations of MIS 5. Soil 8 (MIS 5e) shows the strongest development. Loess 5 accumulated during a glacial interval (~ 76–69 ka; MIS 4) followed by soil development under conditions wetter and probably colder than present. Deposition of thick Loess 3 (~ 43–51 ka, MIS 3) was followed by soil development comparable with that observed in Soil 1. Loess 1 (MIS 2) accumulated during the Pinedale glaciation and was followed by development of Soil 1 under a semiarid climate. This record of alternating loess deposition and soil development is compatible with the history of Yellowstone vegetation and the glacial flour record from the Sierra Nevada.

New field investigations of the Achenheim sequence (Alsace, France) allow for the characterization of variations in the low-field magnetic susceptibility over most of the last climatic cycle, i.e., the past 130,000 yr. New stratigraphic data and thermoluminescence measurements permit reassessment of the previous chronological interpretation of the Upper Pleistocene at Achenheim. A high-resolution analysis of magnetic susceptibility discloses the occurrence of a fine-grained “marker” horizon which was also found recently in another section. This horizon is interpreted as a small-scale dust layer deposited prior to the main interval of loess deposition. The horizon, deposited at the marine isotope stage (MIS) 5/4 boundary, has been found in other loess sequences and is especially prevalent in central Europe. It is characterized by low susceptibility values and a grayish color. New thermoluminescence dates indicate that the loess deposition took place after the MIS 5/4 boundary, i.e., after 70,000 yr. These results are consistent with the Greenland GRIP ice-core dust record which also demonstrates a dusty atmosphere after 72,000 yr ago. On a more regional scale, the Achenheim loess sequence demonstrates a reliable correlation between the western side of the Eurasian loess belt and the dust record of the Greenland ice cores.

Recent studies on relict eolian dunes in the Rio Negro basin, northern Amazon, Brazil (00°35′N, 63°14′W), indicate a drier climate regime during the Late Pleistocene–Holocene transition that is different from the present humid climate. The eolian sands form long chains of linear dunes bordering the Rio Negro River and some tributaries. Here, we present thermoluminescence (TL) ages spanning the period 32,000–8000 yr B.P. The final dune stabilization took place after 8,000 yr B.P. and now the bases of the dunes are fixed by vegetation. Clustering of the TL dates suggests that the dry climate in the Amazon Basin occurred in distinct episodes and argues against current opinions that drastic ecological changes did not affect in the Amazon during the last global glaciation.

This paper reports the first chronometric study of the ‘moats’ of the abundant mounded Iron Age sites of northeast Thailand. Here AMS 14C dates and TL dates are reported which indicate that the moats date from a short period in the Mid to Late Iron Age, before being infilled. The dates also contain preliminary evidence for the chronology of landscape change, which is critical to the understanding of the Iron Age occupation of this region.