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new refs



Here are two new ones.  More to come...

A. Gibbons 1997, Paleontology - Feathered Dino Wins a Few Friends, Science,
275(5307):1731

JT Geological society of america bulletin.
DA APR 01 1997 v 109 n 4
PG 410-28
AU Keller, G.   
AU Lopez-Olivia, J.G.   
AU Adatte, T.   
TI Age, stratigraphy, and deposition of near-K/T siliciclastic deposits in
Mexico: Relation to bolide impact?
Bbstract: Examination of 10 K/T boundary sections in northeastern and
east-central Mexico, and new data presented from 7 sections, permit the
following conclusions. (1) The globally recognized K/T boundary and mass
extinction in planktic foraminifera is stratigraphically above, and
separated by a thin marl layer of Maastrichtian age, from the siliciclastic
deposit that is commonly interpreted as a short-term (hours to days)
K/T-impact-generated tsunami deposit. A similar relationship between the
K/T boundary and siliciclastic or breccia deposits is observed at Brazos
River in Texas, Beloc in Haiti, and Poty Quarry in Brazil. (2)
Stratigraphic control indicates that deposition of the siliciclastic member
occurred sometime during the last 150 k.y. of the Maastrichtian, and ended
at least several thousand years prior to the K/T boundary. (3) At least
four discrete horizons of bioturbation have been observed within the
siliciclastic deposit that indicate episodic colonization by invertebrates
over an extended time period. (4) The glass- and spherule-rich unit, which
has been linked to the Haiti spherule layer and the Chicxulub structure, is
at the base of the siliciclastic deposit and thus significantly predates
the K/T boundary event. The stratigraphic separation of the K/T boundary
and siliciclastic deposits and the evidence of long-term deposition between
them, suggests the presence of two events: (1) a globally recognized K/T
boundary (impact) event marked by Ir anomaly and the mass extinction, and
(2) a Caribbean event (impact or volcanic and probably linked to the
Chicxulub structure) that predates the K/T boundary and is marked by glass
and siliciclastic or breccia deposits.

-Mikiel
Tempe, Arizona

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