Lamont Radiocarbon Measurements VIII

Abstract

Like Lamont VI , this list contains only results on samples of known age (most of which formed during the past ten years). The measurements were made largely in order to gain an understanding of the distribution of radiocarbon within the dynamic carbon reservoir. Again, the data are not reported primarily with the idea of drawing new conclusions but rather to bring together in one place information which is presently scattered throughout the literature or which otherwise might remain unpublished.Although the system of data presentation is essentially the same as that adopted in our previous paper, a change has been made in the normalization formula:previous relationship (Lamont VI) Fonselius and Ostlund,1959. t the relatively high C' concentration probably reflects the presence of bomb-produced C-14. values (approximating-i00 per mil), b) the Gulf Stream is a significant contributor to North Atlantic waters, and c) Atlantic circulation may be cyclic (Broecker and others, 1960).3) The most difficult problem is the evaluation of results on samples from lagoons, estuaries and other restricted parts of the ocean. In these cases the contribution of limestone-derived carbon from terrestrial drainage may cause a significant depression in the initial z. Whether this is the explanation for the low value of the Pearl Harbor sample (L-576'D, this date list) is not certain; more probably, the result implies a finite age of the sample at the time of colhttps://www.cambridge.org/core/terms. https://doi

Two centuries of limited variability in subtropical North Atlantic thermocline ventilation

“…Measured coral ∆ 14 C from Bermuda (this study) and from Florida 11 (Pickles Reef) are used for B and GS, respectively. The pre-bomb ∆ 14 C for S is set to − 71‰ [28][29][30][31] (http://calib.qub.ac.uk/marine). It is important to note that both the GS and S water are sources of low ∆ 14 C to B before bomb testing, but GS during the peak years of the bomb era (1960s) is found to be higher than B 25 .…”

Decadal- to interannual-scale source water variations in the Caribbean Sea recorded by Puerto Rican coral radiocarbon

“…Use of radiocarbon in seawater dissolved inorganic carbon as a water-mass tracer began with some of the first oceanic radiocarbon measurements in the 1950s (e.g., Broecker and Olson 1961), and coral Δ 14 C has been used as a water-mass tracer since the late 1970s (e.g., Druffel 1980Druffel , 1989Druffel 2002;Druffel and Linick 1978;Guilderson et al 2004;Guilderson et al 1998). Corals ultimately utilize seawater DIC for the carbon in their skeletons, so coral skeletal Δ 14 C can be a proxy for seawater Δ 14 C after using δ 13 C to correct for the mass-dependent fractionation that occurs during calcification.…”

“…Water in the subtropical gyres has the highest Δ 14 C because of long residence times at the surface and high rates of gas exchange due to strong winds. In contrast, water in the equatorial regions is subject to vertical mixing with 14 C-depleted water from depth through upwelling off the west coast of Africa, and therefore has consistently lower Δ 14 C. The contrast between the North Atlantic gyre and the south equatorial region was 10‰ before about 1957, when nuclear bomb-produced 14 C began to substantially affect the surface ocean (Table 1, Broecker and Olson 1961).…”

The Effect of Atmospheric 14C Variations on the 14C Levels in the Jordan River System

“…&4Cc was calculated using a13C values measured on the CO2 prepared for the 14C measurements (Broecker & Olson, 1961).…”