Settling the Danian Astronomical Time Scale: A Prospective Global Unit Stratotype at Zumaia, Basque Basin

Abstract

We present a new Danian correlation framework between the land-based Zumaia and Sopelana sections from the Basque Basin and marine-based sections drilled during ODP Legs 198 (Shatsky Rise, North Pacific) and 208 (Walvis Ridge, South Atlantic) that reconciles magnetostratigraphy and the short and long eccentricity cycle patterns among the records. A new whole-rock δ13C isotope record at Zumaia is compared to that of Site 1262. This allows the question of whether the Danian consists of 10 or 11 consecutive 405-kyr eccentricity cycles to be tested. The new consistent stratigraphic framework enables accurate estimates to be made of ages for magnetostratigraphic boundaries, bioevents, and sedimentation rates. Low sedimentation rates appear common in all records in the mid-Danian interval along the upper part of chron C28n, including conspicuous condensed intervals in some of the oceanic records that in the past have hampered the proper identification of cycles. Notably, we challenge the correlation to the Pacific Sites 1209–1210 that were offset by as much as one 405-kyr cycle in previous interpretations (i.e., the Fasciculithus spp. LO, which approximates the Danian–Selandian boundary, and the TC27n event were at odds between oceans in the interpretation of Hilgen et al. 2010). Finally, we envisage that the Zumaia section, which already hosts the Selandian GSSP, could serve as the global Danian stratotype.