The Urn Sohryngkew section of Meghalaya, NE India, located 800-1000 km
from the Deccan volcanic province, is one of the most complete
Cretaceous-Tertiary boundary (KTB) transitions worldwide with all
defining and supporting criteria present: mass extinction of planktic
foraminifera, first appearance of Danian species, delta(13)C shift, Ir
anomaly (12 ppb) and KTB red layer. The geochemical signature of the KTB
layer indicates not only an extraterrestrial signal (Ni and all Platinum
Group Elements (PGEs)) of a second impact that postdates Chicxulub, but
also a significant component resulting from condensed sedimentation (P),
redox fluctuations (As, Co, Fe, Pb, Zn, and to a lesser extent Ni and
Cu) and volcanism. From the late Maastrichtian C29r into the early
Danian, a humid climate prevailed (kaolinite: 40-60%, detrital
minerals: 50-80%). During the latest Maastrichtian, periodic acid rains
(carbonate dissolution; CIA index: 70-80) associated with pulsed Deccan
eruptions and strong continental weathering resulted in mesotrophic
waters. The resulting super-stressed environmental conditions led to the
demise of nearly all planktic foraminiferal species and blooms (>95%)
of the disaster opportunist Guembelitria cretacea. These data reveal
that detrimental marine conditions prevailed surrounding the Deccan
volcanic province during the main phase of eruptions in C29r below the
KTB. Ultimately these environmental conditions led to regionally early
extinctions followed by global extinctions at the KTB. (C) 2011 Elsevier
B.V. All rights reserved.