Bright, Jordon;
Ebert, Chris;
Flores, Carola;
Harnik, Paul G;
Huntley, John Warren;
Kowalewski, Michał;
Portell, Roger W;
Retelle, Michael;
Schuur, Edward A G;
Kaufman, Darrell S
Comparing MICADAS gas source, direct carbonate, and standard graphite 14C determinations of biogenic carbonate
Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Comparing MICADAS gas source, direct carbonate, and standard graphite 14C determinations of biogenic carbonate
Beteiligte:
Bright, Jordon;
Ebert, Chris;
Flores, Carola;
Harnik, Paul G;
Huntley, John Warren;
Kowalewski, Michał;
Portell, Roger W;
Retelle, Michael;
Schuur, Edward A G;
Kaufman, Darrell S
Erschienen:
Cambridge University Press (CUP), 2024
Erschienen in:
Radiocarbon (2024), Seite 1-11
Sprache:
Englisch
DOI:
10.1017/rdc.2024.45
ISSN:
0033-8222;
1945-5755
Entstehung:
Anmerkungen:
Beschreibung:
<jats:title>Abstract</jats:title>
<jats:p>Northern Arizona University, Flagstaff, Arizona, USA, recently installed a MIni CArbon DAting System (MICADAS) with a gas interface system (GIS) for determining the <jats:sup>14</jats:sup>C content of CO<jats:sub>2</jats:sub> gas released by the acid dissolution of biogenic carbonates. We compare 48 paired graphite, GIS, and direct carbonate <jats:sup>14</jats:sup>C determinations of individual mollusk shells and echinoid tests. GIS sample sizes ranged between 0.5 and 1.5 mg and span 0.1 to 45.1 ka BP (n = 42). A reduced major axis regression shows a strong relationship between GIS and graphite percent Modern Carbon (pMC) values (m = 1.011; 95% CI [0.997–1.023], R<jats:sup>2</jats:sup> = 0.999) that is superior to the relationship between the direct carbonate and graphite values (m = 0.978; 95% CI [0.959-0.999], R<jats:sup>2</jats:sup> = 0.997). Sixty percent of GIS pMC values are within ±0.5 pMC of their graphite counterparts, compared to 26% of direct carbonate pMC values. The precision of GIS analyses is approximately ±70 <jats:sup>14</jats:sup>C yrs to 6.5 ka BP and decreases to approximately ±130 <jats:sup>14</jats:sup>C yrs at 12.5 ka BP. This precision is on par with direct carbonate and is approximately five times larger than for graphite. Six Plio-Pleistocene mollusk and echinoid samples yield finite ages when analyzed as direct carbonate but yield non-finite ages when analyzed as graphite or as GIS. Our results show that GIS <jats:sup>14</jats:sup>C dating of biogenic carbonates is preferable to direct carbonate <jats:sup>14</jats:sup>C dating and is an efficient alternative to standard graphite <jats:sup>14</jats:sup>C dating when the precision of graphite <jats:sup>14</jats:sup>C dating is not required.</jats:p>