scholarly journals The Marine Radiocarbon Reservoir Effect in Tomales Bay, California

Radiocarbon ◽  
2018 ◽  
Vol 60 (3) ◽  
pp. 963-974 ◽  
Author(s):  
Lee M Panich ◽  
Tsim D Schneider ◽  
Paul Engel
Keyword(s):  
Temporal Variation ◽  
Late Holocene ◽  
Pacific Coast ◽  
Archaeological Sites ◽  
Northern Coast ◽  
Museum Collection ◽  
Reservoir Effect ◽  
The Pacific ◽  
R Value ◽  
Tomales Bay

ABSTRACTThis paper examines the marine reservoir effect for Tomales Bay, a 25.5-km-long tidal estuary along the northern coast of California. We determined the regional ∆R through radiocarbon (14C) measurements of pre-1950 shells from a museum collection as well as archaeologically recovered shell samples from a historical railroad grade of known construction date. These results are compared against four sets of paired shell and bone samples from two local archaeological sites. Our results indicate little spatial variation along the inner bay, but the proposed ∆R value is lower than those previously reported for nearby areas along the Pacific Coast. We also note potential variability in regional ∆R of approximately 200 14C years for the late Holocene, and comparison with an older paired bone and shell sample points toward more significant temporal variation earlier in time.

scholarly journals Variability in North Atlantic marine radiocarbon reservoir effects at c. AD 1000

The Holocene ◽  
2006 ◽  
Vol 16 (1) ◽  
pp. 131-136 ◽  
Author(s):  
P. L. Ascough ◽  
G. T. Cook ◽  
M. J. Church ◽  
A. J. Dugmore ◽  
S. V. Arge ◽  
...  
Keyword(s):  
Temporal Variation ◽  
North Atlantic ◽  
Climatic Conditions ◽  
Spatial And Temporal Variation ◽  
Archaeological Sites ◽  
Driving Mechanism ◽  
Reservoir Effect ◽  
The North ◽  
The North Atlantic ◽  
Precision And Accuracy

14C age measurements made on samples from three archaeological sites located on North Atlantic coasts were used to investigate the marine reservoir effect (MRE) at c.AD 1000. This is an important period within human cultural and palaeoenvironmental research as it is a time when Norse expansion to the North Atlantic islands occurred, during what appears to be a period of ameliorating climatic conditions. This makes improved chronological precision and accuracy at this time highly desirable. The data indicate a potential latitudinal variation in MRE at c. AD 1000 from a ΔR of-142±16 14C yr at Omey Island (53° 32' N) to 64±13 14C yr at Undir Junkarinsfløtti (61° 51' N). The results are compared with modern assessments of MRE values within the context of oceanographic and climatic regimes that provide a possible driving mechanism for spatial and temporal variation in MRE.

scholarly journals Potential Use of Archaeological Snail Shells for the Calculation of Local Marine Reservoir Effect

Radiocarbon ◽  
2015 ◽  
Vol 57 (3) ◽  
pp. 459-467 ◽  
Author(s):  
Carla Carvalho ◽  
Kita Macario ◽  
Maria Isabela De Oliveira ◽  
Fabiana Oliveira ◽  
Ingrid Chanca ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Southeastern Brazil ◽  
Archaeological Sites ◽  
Brazilian Coast ◽  
Museum Collections ◽  
Human Occupation ◽  
Reservoir Effect ◽  
The Holocene ◽  
Carbon Reservoir ◽  
Potential Use

Shellmounds are archaeological sites found across the Brazilian coast and form an important record of the human occupation of this area during the Holocene. The presence of both terrestrial and marine remains within the same archaeological context enables the comparison of different carbon reservoirs. There is only a small number of similar studies for the coast of south-southeastern Brazil. Previous work was based on the analysis of pre-bomb shells from museum collections and paired charcoal/marine shells from archaeological sites. This article assesses the potential use of terrestrial shells as representative of atmospheric carbon reservoir in the calculation of the marine reservoir effect (MRE) of the southeastern Brazilian coast. The presence of both terrestrial and marine shells over several archaeological layers represents a great potential for calculating reservoir corrections and their temporal variation.

Prehistoric Footprints from El Salvador

1957 ◽  
Vol 22 (3) ◽  
pp. 282-285 ◽  
Author(s):  
Wolfgang Haberland ◽  
Willi-Herbert Grebe
Keyword(s):  
El Salvador ◽  
Coastal Plain ◽  
Pacific Coast ◽  
Central American ◽  
Archaeological Sites ◽  
The North ◽  
The Pacific ◽  
Volcanic Chain ◽  
River Deposits ◽  
Original Vegetation

In the Central American Republic of El Salvador the Rio Lempa divides the eastern third of the country from the rest. In its lower course it flows through a large coastal plain, built up in geologically recent times by river deposits and sediments from the volcanic chain in the north (San Vicente and the volcanic group of the east). From west (Balsam range) to east (Colinas de Jucuarán) this plain has a length of about 100 km. and a width of 20 km. Some 20 years ago the nearly flat land, which slopes only very slightly from the volcanic chain to the Pacific coast, was still heavily wooded, but since then most of the forest has been cleared away for cotton crops, only leaving tiny patches of the original vegetation. In this process a number of archaeological sites were revealed, especially east of the Rio Lempa, in the department of Usulután.

Exchange Implications of Obsidian Source Analysis from the Lower Rio Verde Valley, Oaxaca, Mexico

1995 ◽  
Vol 6 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Arthur A. Joyce ◽  
J. Michael Elam ◽  
Michael D. Glascock ◽  
Hector Neff ◽  
Marcus Winter
Keyword(s):  
Pacific Coast ◽  
Classic Period ◽  
Source Analysis ◽  
Archaeological Sites ◽  
Basin Of Mexico ◽  
The Pacific ◽  
Monte Alban ◽  
Middle Formative ◽  
Exchange Patterns ◽  
Obsidian Source

This article considers the results of instrumental neutron-activation analyses of 61 obsidian artifacts recovered from excavations at four archaeological sites in the lower Río Verde valley on the Pacific coast of Oaxaca, Mexico. Determinations of source locations of these artifacts permit the examination of changes in obsidian exchange patterns spanning the late Middle Formative to the Classic period. The results show that through most of this period the importation of obsidian into the lower Verde region was dominated by sources in the Basin of Mexico and Michoacan. The data allow us to evaluate previous models of interregional relations during the Formative and Classic periods, including interaction with the highland centers of Monte Albán and Teotihuacán.

scholarly journals Temporal Variation and Statistical Assessment of the b Value off the Pacific Coast of Tokachi, Hokkaido, Japan

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 249 ◽  
Author(s):  
Weiyun Xie ◽  
Katsumi Hattori ◽  
Peng Han
Keyword(s):  
Temporal Variation ◽  
Pacific Coast ◽  
Statistical Significance ◽  
B Value ◽  
Statistical Assessment ◽  
Significance Level ◽  
B Values ◽  
The Pacific ◽  
Bootstrap Approach ◽  
Large Earthquakes

: The Gutenberg-Richter Law describes the frequency-magnitude distribution of earthquakes. A number of studies have shown that the slope (b value) of the relationship between frequency and magnitude decreased before large earthquakes. In this paper, we investigate the temporal variation of the b value off the Pacific coast of Tokachi, Hokkaido, Japan, during 1990–2014. The magnitude of completeness (Mc) in the catalog is evaluated by combining the maximum curvature (MAXC) technique and the bootstrap approach. Then, the b value, and its uncertainty, is computed by using the maximum likelihood estimation. The Akaike Information Criterion (AIC) with the bootstrap approach is introduced to statistically assess the temporal variation of b values and quantify the significance level. The results show a decrease in trends of the b value prior to two large earthquakes (26 September 2003 (M8.0) and 11 September 2008 (M7.1)) in the analyzed area. In addition, the decrease of b values shows certain statistical significance three months before the 2003 Earthquake off the Pacific coast of Tokachi (M8.0). It is concluded that the b value with statistical assessment may contain potential information for future large earthquake preparation off the Pacific coast of Tokachi, Hokkaido, Japan.

The Systematic Use of Radiocarbon Dating in Archaeological Surveys in Coastal and Other Erosional Environments

1999 ◽  
Vol 64 (3) ◽  
pp. 431-443 ◽  
Author(s):  
Jon M. Erlandson ◽  
Madonna L. Moss
Keyword(s):  
Pacific Coast ◽  
Cultural Resource Management ◽  
Analytical Tool ◽  
Archaeological Sites ◽  
Coastal Zones ◽  
Widespread Application ◽  
The Pacific ◽  
The World ◽  
Significant Patterns ◽  
Destructive Processes

Traditionally, archaeologists have used l4C dating primarily as a postexcavation analytical tool to establish the age of features, strata, or assemblages. In coastal zones and other environments around the world, however, thousands of archaeological sites are rapidly eroding or endangered by other destructive processes. We believe archaeologists should expand their use of l4C dating, systematically incorporating it into surveys in coastal, lacustrine, riverine, and other environments where erosional exposures often provide access to extensive stratigraphic profiles. With examples from the Pacific Coast of North América, we show how widespread l4C dating of sites during surveys can be used to help manage archaeological sites more effectively and identify significant patterns of paleoenvironmental change, site survival, settlement and demography, technology, and social organization. Without more widespread application of such techniques, and a reallocation of research and cultural resource management funds, thousands of sites will be lost before even the most basic information about their age and contents is known.

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