Abstract. The numerical age of the Jurassic–Cretaceous boundary has
been controversial and difficult to determine. In this study, we present
high-precision U–Pb geochronological data around the Jurassic–Cretaceous
boundary in two distinct sections from different sedimentary basins: the Las
Loicas, Neuquén Basin, Argentina, and the Mazatepec, Sierra
Madre Oriental, Mexico. These two sections contain primary and secondary
fossiliferous markers for the boundary as well as interbedded volcanic ash
horizons, allowing researchers to obtain new radioisotopic dates in the late Tithonian
and early Berriasian. We also present the first age determinations in the
early Tithonian and tentatively propose a minimum duration for the stage as
a cross-check for our ages in the early Berriasian. Given our radioisotopic
ages in the early Tithonian to early Berriasian, we discuss implications
for the numerical age of the boundary.
High-precision U–Pb ages in the early Tithonian to early Berriasian and implications for the numerical age of the Jurassic–Cretaceous boundary