Update on the cosmogenic in situ 14C laboratory at the Lamont-Doherty Earth Observatory

• Published in: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
• Main Authors: Lamp, Jennifer, Young, Nicolás, Koffman, Tobias, Schimmelpfennig, Irene, Tuna, Thibaut, Bard, Edouard, Schaefer, Joerg
• Other Authors: Lamont-Doherty Earth Observatory (LDEO), Columbia University New York, Collège de France - Chaire Evolution du climat et de l'océan, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: surface exposure dating; in situ carbon-14; cosmogenic nuclides; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; Antarctic; Arctic; Cronus; New Zealand; Antarc*
• Online Access: https://hal.science/hal-02152385; https://doi.org/10.1016/j.nimb.2019.05.064

International audience Cosmogenic in situ C-14 in quartz is rapidly becoming a widely used geochronological tool for studying earth surface processes over the last 30,000 years. The Lamont-Doherty Earth Observatory houses one of the longest continuously-operating cosmogenic in situ C-14 laboratories; in this contribution, we provide an update on the status of the laboratory following Goehring et al. (2014). From 2010 to the present, our long-term average blank value is 119,000 +/- 37,000 C-14 atoms, with no statistically significant trend over the last nine years. While our average measured C-14 concentration of the CRONUS-A inter-laboratory comparison standard is in line with data published from other laboratories, we note a step increase between 2013 and 2015 that is still under investigation. Additionally, we report our first procedural blanks and CRONUS-A values analyzed on the gas source of the ANMICADAS at CEREGE, France. Many of the > 75 samples analyzed at Lamont for in situ C-14 from the Arctic, Antarctic, New Zealand, and the Alps have been paired with Be-10 analyses contributing to the increasing density of burial dating data covering the last 20,000 years. Currently we are working on increasing sample throughput, streamlining the C-14 extraction procedure, and considerably decreasing blank levels.