Radiocarbon Dating of Large Holocene Volcanic Events Within South Kamchatka (Russian Far East)

From the 19th International Radiocarbon Conference held in Keble College, Oxford, England, April 3-7, 2006.Radiocarbon dating is widely used when studying recent volcanic activity in the Kamchatka Peninsula due to the abundance of organic matter that is associated with the volcanic deposits. Here, we present the results of 14C dating of major volcanic events within the active South Kamchatka volcanic zone. South Kamchatka includes 8 recently active volcanic centers (stratovolcanoes, calderas, and large craters) that have been erupting during the Holocene. Their tephras represent useful markers for both the southern part of the peninsula and the Northern Kurile Islands. Since these marker tephra layers facilitate stratigraphic and tephrochronological studies in this area, it was important to determine their ages. We have obtained 73 new individual 14C dates on paleosol, peat, charcoal, and wood associated with the marker tephra layers, then complemented these data with 37 earlier published dates and analyzed the resulting data set. We selected the reliable dates and then obtained average 14C ages of marker tephra layers. The details of these procedures, as well as brief descriptions of South Kamchatka Holocene eruptions and their tephra beds, are presented in the paper.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Puzzling Radiocarbon Dates for the Upper Paleolithic Site of Sungir (Central Russian Plain)

A summary is presented of more than a decade-long study of direct radiocarbon dating for one of the most important human burials in Eurasia, the Sungir site in eastern Europe. Eighteen C-14 dates were produced before early 2014 on three skeletons (Sungir 1-3), and there is still no consistency in the results. In the absence of other independent methods to establish the antiquity of Sungir, a careful analysis is performed of the site's stratigraphy, paleoenvironment, and C-14 dates run on animal bones from the same layer as the burials. Although the conclusions of this work cannot be guaranteed to be absolutely correct, we suggest that at the present stage of research the age range of similar to 26,000-27,210 BP is the most probable time for the creation of the elaborate human burials at the Sungir site

(Table 3) Carbon isotopic composition in bottom sediments and carbonate nodules from the Gulf of California at Station DM9-666

New data on phosphorites collected by dredging and trawling at depths from 2700 to 520 m in the open Atlantic Ocean (i.e. outside of the shelf and the continental slope) are reported. Aphanitic, granular, brecciated, and conglomerate-like types are distinguished among the phosphorites. A comparison of the studied phosphorites with ones from the Atlantic shelf of Africa and from seamounts of other oceans is made

(Table 4) Radiocarbon age of carbonate nodules from the Gulf of California at Station DM9-666

New data on phosphorites collected by dredging and trawling at depths from 2700 to 520 m in the open Atlantic Ocean (i.e. outside of the shelf and the continental slope) are reported. Aphanitic, granular, brecciated, and conglomerate-like types are distinguished among the phosphorites. A comparison of the studied phosphorites with ones from the Atlantic shelf of Africa and from seamounts of other oceans is made

(Table 5) Calcium carbonate, organic carbon, and hydrogen sulfide contents in bottom sediments of Core DM9-666, Gulf of California

New data on phosphorites collected by dredging and trawling at depths from 2700 to 520 m in the open Atlantic Ocean (i.e. outside of the shelf and the continental slope) are reported. Aphanitic, granular, brecciated, and conglomerate-like types are distinguished among the phosphorites. A comparison of the studied phosphorites with ones from the Atlantic shelf of Africa and from seamounts of other oceans is made

(Table 1) Abundance of diagenetic carbonate nodules in bottom sediments from the Gulf of California at Station DM9-666

New data on phosphorites collected by dredging and trawling at depths from 2700 to 520 m in the open Atlantic Ocean (i.e. outside of the shelf and the continental slope) are reported. Aphanitic, granular, brecciated, and conglomerate-like types are distinguished among the phosphorites. A comparison of the studied phosphorites with ones from the Atlantic shelf of Africa and from seamounts of other oceans is made

Chemical and isotope composition of carbonate nodules and host bottom sediments from Core DM9-666, Gulf of California

Results of mineralogical and isotopic analyzes of sulfur and carbon in carbonate nodules and host bottom sediments and results of 14C measurement in carbonate nodules are reported. It is proved that the carbonate nodules formed 11-22 thousand years ago in anaerobic diagenesis of bottom sediments rich in organic matter. Isotopic light metabolic carbon dioxide was a source of carbonate for nodules. It formed during microbial degradation of organic matter of bottom sediments

(Table 6) Sulfate ion concentration and alkalinity in interstitial waters from bottom sediments of Core DM9-666, Gulf of California

New data on phosphorites collected by dredging and trawling at depths from 2700 to 520 m in the open Atlantic Ocean (i.e. outside of the shelf and the continental slope) are reported. Aphanitic, granular, brecciated, and conglomerate-like types are distinguished among the phosphorites. A comparison of the studied phosphorites with ones from the Atlantic shelf of Africa and from seamounts of other oceans is made