The seawater neodymium and lead isotope record of the final stages of Central American Seaway closure

Drake Passage and Central American Seaway controls on the distribution of the oceanic carbon reservoir

“…Based on geological and geochemical evidence, Central American Seaway closure occurred between 15 and 2.5 Ma (Montes et al, 2012;Sepulchre et al, 2014). While present, this low-latitude oceanic gateway allowed fresh Pacific waters to enter the relatively saline Atlantic, and geochemical, sedimentary, and isotopic evidence suggest this inflow caused a weakened Atlantic meridional overturning relative to the present (Burton et al, 1997;Haug and Tiedemann, 1998;Haug et al, 2001;Osborne et al, 2014), a finding supported by modeling studies (e.g. Murdock et al, 1997;Butzin et al, 2011;Zhang et al, 2012;Yang et al, 2014).…”

Glacial induced closure of the Panamanian Gateway during Marine Isotope Stages (MIS) 95–100 (∼2.5 Ma)

“…This was done by linking the benthic δ 18 O records of Sites 999 and 1241 for the studied time interval to the benthic δ 18 O-stack of Lisiecki and Raymo (2005) using the Analyseries software (Paillard et al, 1996). All data presented here are stored in the Pangaea data bank (www.pangaea.de).…”

“…Values are reported in δ-notation relative to Vienna Pee Dee Belemnite (VPDB), calibrated by using the National Institute of Standards NBS 18 and 19 standards. records from each other to determine the difference between the Caribbean and the East Pacific, the respective records were linearly interpolated using the Analyseries software package (Paillard et al, 1996) at 1 kyr intervals, which is similar to the original sampling resolution (∼1 kyr). Vertical bar indicates the 1σ associated with calculating sea water temperatures (Nürnberg et al, 2000;Anand et al, 2003).…”

“…(For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) on changes in benthic foraminifera assemblages (Duque-Caro, 1990) and neodynium isotopic data both measured on fish teeth and foraminifera, and simulated (Newkirk and Martin, 2009;Osborne et al, 2014;Sepulchre et al, 2014). In a recent study, Montes et al (2012) used U-Pb-Th dating on zircons from granitoid samples, geochemical analyses of basaltic samples, and paleomagnetic samples from cores drilled in Panama to argue that the Panamanian Gateway might have closed as early as 15 Ma.…”

Pliocene oceanic seaways and global climate

“…Recent tectonic evidence from land suggests that deep and intermediate connections between both ocean basins were already closed during the middle Miocene2. However, manifold evidence from ocean records indicate the existence of shallow (≤200 m) connections between both ocean basins until the Pliocene and that the closure of these were sufficient to affect global climate34567891011. Most notably, paleoceanographic data from either side of the Panamanian land bridge indicate that the further restriction of the CAS reached a critical threshold between ~4.8–4 Ma with marked impacts on ocean circulation and global climate5678.…”