Introduction To Optical Dating

Optical dating is a rapidly developing technique, used primarily in the dating of sediments deposited in the last 500,000 or more years. As such increasing numbers of Quaternary geologists, physical geographers, archaeologists, and anthropologists are now relying on the results produced. Written by one of the foremost experts on optical dating, this book aims to bring together in a coherent whole the various strands of research that are ongoing in the area. It gives beginners an introduction to the technique as well as acting as a valuable source of up to date references. The text is divided into three parts; main text, technical notes and appendices. In this way the main text is accessible by those researchers with a limited knowledge of physics, with the technical notes providing depth of understanding for those who require it. The first part of the book is concerned with basic notions and an introduction to the standard techniques, as well as several illustrative case histories. It goes on to then discuss the limitations of the technique and factors affecting reliability.

Optical dating is used mainly in the dating of sediments deposited in the last 500,000 or more years. This book brings together various strands of research, giving beginners an introduction to the technique and an up-to-date reference.

The field of Luminescence Dating has reached a level of maturity. Both research and applications from all fields of archaeological science, from archaeological materials to anthropology and geoarchaeology, now routinely employ luminescence dating. The advent of optically stimulated luminescence (OSL) techniques and the potential for exploring a spectrum of grain aliquots enhanced the applicability, accuracy and the precision of luminescence dating. The present contribution reviews the physical basis, mechanisms and methodological aspects of luminescence dating; discusses advances in instrumentations and facilities, improvements in analytical procedures, and statistical treatment of data along with some examples of applications across continents, covering all periods (Middle Palaeolithic to Medieval) and both Old and New World archaeology. They also include interdisciplinary applications that contribute to palaeo-landscape reconstruction.

Optically stimulated luminescence (OSL) dating has proven to be extremely useful for establishing the Late Quaternary chronological framework in many areas of the Brazilian territory. In this region dominated by tropical climate, OSL dating can be more extensively applied than radiocarbon dating due to the generally low potential for the preservation of organic matter in sedimentary samples. This problem is especially critical in areas of the Amazonian lowlands, because of the hot climate and high precipitation rates. The abundance of quartz grains deposited in fluvial and aeolian environments over this region favours OSL dating. More than 20 years of continuous and collaborative work has resulted in the creation of an extensive OSL age database for Late Quaternary sedimentary deposits in the Amazonian lowlands. This effort has contributed to improving the paleoenvironmental and paleoclimatic reconstructions of this region within this period. This book discusses the state of art of OSL dating of Late Quaternary deposits in the Amazonian lowlands, focusing on providing an introduction to dating principles using OSL, and defining the application of OSL techniques as a dating method. It also offers a statistical study and calculation of equivalent dose and annual dose rates, details the sampling and experimental apparatus, and considers the difficulties and adaptation techniques in dating Late Quaternary strata in the Amazonian lowlands.

Optically Stimulated Luminescence (OSL) dating is a tool used in Quaternary Geology for assessing ages of depositional mineral grains such as quartz, feldspars and zircons. In particular, OSL showed to be exceptionally robust and reliable for dating quartz samples. OSL dating relies on the assumption that the luminescence signal of grains is fully reset to zero by sunlight exposure before deposition. If this requirement is not fulfilled (i.e. grains were 'poorly-bleached'), ages may be grossly overestimated. In particular, poor-bleaching can significantly affect age estimations of young sediments. Standard procedures for estimating the burial dose of a sediment make use of a large number of grains (aliquot) that is measured simultaneously. This approach has been shown to work well, but only on homogeneously bleached sediments. An alternative way to investigate poor-bleaching within a sample is to measure the OSL signal from individual grains rather than from aliquots made up of several thousands of grains. The advantage is that individual grains with large doses (possibly due to poor-bleaching) can be identified and dealt with. detectable signals and luminescence responses are weak. The aim of this publication is to determine the feasibility of applying dating techniques to individual grains of quartz from deposits formed within the last 300 years.

This book is a collection of the articles presented at the NATO Advanced Research Workshop (ARW 979859) held in St. Petersburg, from the 15-18 November 2003 in the Hermitage Museum. The title of the workshop was “The impact of the environment on Human Migration in Eurasia”. More than 40 scientists from Russia, Ukraine, Kazakhstan, Poland, Germany, Switzerland, The Netherlands, United Kingdom, Belgium, Finland, Lithuania and Latvia took part. The themes of the workshop focused on the origin, development, interactions, and migrations of prehistoric and ancient populations, specifically the Scythians, in Eurasia and their relationships with the environment of the time. The discussion of these questions necessitated the participation of specialists from a wide range of academic fields. Beyond any doubt, the environment played an important role in the life of ancient nomadic populations, forming the basis of their economies and influencing various aspects of their mode of life. In this respect, the collaboration of specialists in the Humanities and Science is essential for the solution of scientific questions concerning these peoples. Over the past few years, a large amount of new proxy data related to environmental changes during the Pleistocene and the Holocene and their impact on human life has become available. Our discussion was predominantly limited to environmental changes related to the Holocene. In st this period of about 10000 years, the main focus was on the 1 millennium BC.

Optically Stimulated Luminescence (OSL) has become the technique of choice for many areas of radiation dosimetry. The technique is finding widespread application in a variety of radiation dosimetry fields, including personal monitoring, environmental monitoring, retrospective dosimetry (including geological dating and accident dosimetry), space dosimetry, and many more. In this book we have attempted to synthesize the major advances in the field, covering both fundamental understanding and the many applications. The latter serve to demonstrate the success and popularity of OSL as a dosimetry method. The book is designed for researchers and radiation dosimetry practitioners alike. It delves into the detailed theory of the process from the point of view of stimulated relaxation phenomena, describing the energy storage and release processes phenomenologically and developing detailed mathematical descriptions to enable a quantitative understanding of the observed phenomena. The various stimulation modes (continuous wave, pulsed, or linear modulation) are introduced and compared. The properties of the most important synthetic OSL materials beginning with the dominant carbon-doped Al2O3, and moving through discussions of other, less-well studied but nevertheless important, or potentially important, materials. The OSL properties of the two most important natural OSL dosimetry material types, namely quartz and feldspars are discussed in depth. The applications chapters deal with the use of OSL in personal, environmental, medical and UV dosimetry, geological dating and retrospective dosimetry (accident dosimetry and dating). Finally the developments in instrumentation that have occurred over the past decade or more are described. The book will find use in those laboratories within academia, national institutes and the private sector where research and applications in radiation dosimetry using luminescence are being conducted. Potential readers include personnel involved in radiation protection practice and research, hospitals, nuclear power stations, radiation clean-up and remediation, food irradiation and materials processing, security monitoring, geological and archaeological dating, luminescence studies of minerals, etc.