Agost, Spain (K/T)

K/T Boundary ejecta layer near Agost, Spain.


P0 Zone age "boundary clay", a laminated, dark, organic rich clayey marl (20% caco3), extremely poor in planktic foraminifers. The transition from foraminifer-rich (Maastrichtian) to foraminifer poor is marked by the ejecta layer. Above the ejecta layer no transitional interval is visible (except a burrow) that documents a gradual disappearance of foraminifers.

The extinction of planktic foraminifers is extremely rapid

Ejecta layer, containing here 24.4 ng/g Ir. Numerous cross-sections of altered microkrystites, and a few droplets of altered tektites (brown) are visible

K/T boundary level, placed here -according to the official definition of the GSSP in Tunisia- at the base of the Ir-rich layer, above the mass-extinction level of Maastrichtian planktic foraminifers.

Uppermost Maastrichtian hemipelagic marls. The largest foraminifers are Globotruncanids. The distribution of the Foraminifers is random, and no decrease in abundance towards the ejecta layer can be observed.

The dark green streak is part of a burrow which is flattened and smeared. The burrow fill is from P0 unit boundary clay, not from the greenish ejecta layer