Pearce Paul Creasman

Bio: Pearce Paul Creasman is an academic researcher from University of Arizona. The author has contributed to research in topics: Dendroarchaeology & Pyramid. The author has an hindex of 9, co-authored 28 publications receiving 202 citations. Previous affiliations of Pearce Paul Creasman include Texas A&M University.

Relationship between solar activity and Δ14C peaks in AD 775, AD 994, and 660 BC

Abstract: Since the AD 775 and AD 994 Δ^(14)C peak (henceforth M12) was first measured by Miyake et al. (2012, 2013), several possible production mechanisms for these spike have been suggested, but the work of Mekhaldi et al. (2015) shows that a very soft energy spectrum was involved, implying that a strong solar energetic particle (SEP) event (or series of events) was responsible. Here we present Δ^(14)C values from AD 721–820 Sequoiadendron giganteum annual tree-ring samples from Sequoia National Park in California, USA, together with Δ^(14)C in German oak from 650–670 BC. The AD 721–820 measurements confirm that a sharp Δ^(14)C peak exists at AD 775, with a peak height of approximately 15‰ and show that this spike was preceded by several decades of rapidly decreasing Δ^(14)C. A sharp peak is also present at 660 BC, with a peak height of about 10‰, and published data (Reimer et al. 2013) indicate that it too was preceded by a multi-decadal Δ^(14)C decrease, suggesting that solar activity was very strong just prior to both Δ^(14)C peaks and may be causally related. During periods of strong solar activity there is increased probability for coronal mass ejection (CME) events that can subject the Earth’s atmosphere to high fluencies of solar energetic particles (SEPs). Periods of high solar activity (such as one in October–November 2003) can also often include many large, fast CMEs increasing the probability of geomagnetic storms. In this paper we suggest that the combination of large SEP events and elevated geomagnetic activity can lead to enhanced production of ^(14)C and other cosmogenic isotopes by increasing the area of the atmosphere that is irradiated by high solar energetic particles.

Ship Timber and the Reuse of Wood in Ancient Egypt

Abstract: Reuse of materials in ancient Egypt is neither a new nor novel concept. The ancient Egyptians reused a variety of materials and certainly any resource that had spiritual, ideological, or economic value that was available to them. Yet, reuse of certain raw materials has not been thoroughly examined, notably timber. This manuscript explores the modes, preferences and implications of wood use, specifically reuse, in Egypt’s Pharaonic Period, using ship timber as the illustrative example. This synthesis suggests specific preferences for commodity consumption and conservation existed, revealing cultural and behavioral trends.

A further investigation of the Cairo Dahshur boats

Abstract: Based on primary data and direct observation, a re-examination of two boats excavated by Jacques De Morgan outside Senwosret III's pyramid complex at Dahshur, and now in the Egyptian Museum, Cairo, is offered. The original excavation report is reconciled with subsequent scholarly records, and the boats' construction techniques are evaluated. De Morgan's account has previously been dismissed due to discrepancies between his descriptions and the findings of modern examinations of two other boats from the same cache now located in the United States. Unique features found on the two Cairo Dahshur boats explain the discrepancies and permit a new interpretation of the boats' construction.

The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0-55 cal kBP)

Abstract: Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.

SHCal20 Southern Hemisphere Calibration, 0–55,000 Years cal BP

Abstract: Early researchers of radiocarbon levels in Southern Hemisphere tree rings identified a variable North-South hemispheric offset, necessitating construction of a separate radiocarbon calibration curve for the South. We present here SHCal20, a revised calibration curve from 0–55,000 cal BP, based upon SHCal13 and fortified by the addition of 14 new tree-ring data sets in the 2140–0, 3520–3453, 3608–3590 and 13,140–11,375 cal BP time intervals. We detail the statistical approaches used for curve construction and present recommendations for the use of the Northern Hemisphere curve (IntCal20), the Southern Hemisphere curve (SHCal20) and suggest where application of an equal mixture of the curves might be more appropriate. Using our Bayesian spline with errors-in-variables methodology, and based upon a comparison of Southern Hemisphere tree-ring data compared with contemporaneous Northern Hemisphere data, we estimate the mean Southern Hemisphere offset to be 36 ± 27 14C yrs older.

GPR Remote Sensing in Archaeology

Abstract: GPR Remote Sensing in Archaeology provides a complete description of the processes needed to take raw GPR data all the way to the construction of subsurface images. The book provides an introduction to the "theory" of GPR by using a simulator that shows how radar profiles across simple model structures look and provides many examples so that the complexity of radar signatures can be understood. It continues with a review of the necessary radargram signal processes needed along with examples. The most comprehensive methodology to construct subsurface images from either coarsely spaced data using interpolation or from dense data from multi-channel equipment and 3D volume generation is presented, advanced imaging solutions such as overlay analysis are introduced, and numerous worldwide site case histories are shown. The authors present their studies in a way that most technical and non-technical users of the equipment will find essentials for implementing in their own subsurface investigations.

The Oxford History of Ancient Egypt

Abstract: (2001). The Oxford History of Ancient Egypt. History: Reviews of New Books: Vol. 29, No. 2, pp. 89-89.