T197 Mass Extinctions I: Past, Present, and Future?

Tuesday, 24 October 2017
8:00 AM - 12:00 PM
Room 608

REVISITING THE DECCAN TRAP WOODS – AFFINITIES AND FUNCTIONAL TRAITS

Paper number: T197-6
Program: Technical Sessions
Time: 9:15 AM – 9:30 AM

Authors

Abstract

Since the 1920s, numerous petrified woods have been reported from the Deccan Intertrappean Beds. Most were described and named during the 1950s to 1980s. At that time, it was thought the beds were younger (Eocene) and so, not surprisingly, the woods were identified by their general similarity with present-day Indian woods. There are at least 80 wood types, most collected from five distinct productive localities. We recently examined thin sections of the holotypes of 43 species, reviewed literature descriptions for the others, and reassessed the woods’ affinities by comparing them anatomically with present-day woods worldwide. Some Deccan woods have combinations of features consistent with the family or genus to which they were originally assigned and represent the oldest known macrofossils of those taxa. The spectrum of important functional traits of the Deccan woods differs markedly from Maastrichtian – Paleocene wood assemblages known from the rest of the world, almost all of which are from higher paleolatitudes. Overall, the Deccan woods appear “modern” and have a high incidence of the hydraulically advantageous feature of simply perforated vessel elements for water conduction and of axial parenchyma, which functions in water and nutrient storage and wound repair. Higher latitude Cretaceous and Paleocene woods assemblages have higher incidences of so-called "primitive" hydraulic attributes such as scalariform vessel perforations and lower incidences of vessel-associated axial parenchyma. Apparently, latitudinal differences in wood anatomical functional traits were as great or greater at the K-Pg as they are today. The absence of distinct growth rings in most Deccan woods suggests a climate with minimal seasonality, contrasting with monsoonal seasonality of today. Resolution of which Deccan localities are Maastrichtian and which are Paleocene is needed for investigating whether there are differences between wood assemblages of the latest Cretaceous and the earliest Paleocene

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-303620

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