Re: the deccan traps and the bolide

[chartiem@ERE.UMontreal.CA (Chartier Michel)]

> 
> [I will say this again and again, but nobody listens... :-( ]
> 
> The Deccan Traps are UNQUESTIONABLY dated as begin at least in the
> Maastrichtian, and maybe even as early as the Santonian.  The traps are not
> a single mass, but a series of floods.  In some of the "intertrappen"
> (i.e., between flood) sedimentary layers are Cretaceous dinosaurs,
> ammonites, and pollen.  Unless the K-T impact could send shockwaves back
> through time (on the order of 10 or 20 million years!), it could not have
> caused the Deccan Traps.
> 
> Not to say that another impact may have caused it, of course.  Also, the
> K-T impact may have amplified the flow, but a) there's no evidence of that
> and b) it was pretty intense already.
> 
> Unfortunately, the K-T boundary has attracted a lot of attention of people
> who do not know the basics of the stratigraphy involved.
> 
>                               
> Thomas R. Holtz, Jr.                                 
> tholtz@geochange.er.usgs.gov
> Vertebrate Paleontologist in Exile                Phone:      703-648-5280
> U.S. Geological Survey                              FAX:      703-648-5420
> Branch of Paleontology & Stratigraphy
> MS 970 National Center
> Reston, VA  22092
> U.S.A.
> 
Some people do listen to you, Tom. Regarding the discussion of the age
of the Deccan Traps, here is the reference to a recent article that might
interest some of you:

Khajuria, Chanchal K., Prasad, Guntupalli V.R. and Manhas, Brijesh K. 1994.
        Palaeontological constraints on the age of Deccan Traps, peninsular
        India. Newsletters on Stratigraphy 31 (1), 21-32.

For those of you who don't have access to this periodical, or who will
settle for this, here is the abstract:

        The conventional view of a post-Turonian initiation and a 
        prolonged duration of 50 Ma (extending up to Early Oligocene)
        for the Deccan volcanic activity is discarded in the light of 
        new palaeontological data from the infra- and intertrappean
        beds of peninsular India. The fish and molluscan fauna and the
        plant fossils, which were the basis for the above conclusion,
        are found to be unreliable for establishing temporal relation-
        ships. It has also been demonstrated that dinosaurs, which were
        considered to have become extinct by the time of intertrappean
        deposition, do occur in the intertrappean beds. Latest 
        palaeontological evidence from different groups of vertebrates,
        invertebrates, and palynofossils recovered from the infratrappean
        (=Lameta) beds support a Late Maastrichtian initiation for the
        Deccan volcanism. A Late Maastrichtian age is also suggested
        for the intertrappean beds of Naskal, Asifabad, Nagpur, Padwar,
        Ranipur, and Kutch not only based on the fishes, dinosaurs,
        ostracodes, and palynofossils, but also because of the striking
        similarity between the fauna and flora of infra- and 
        intertrappean beds. But a few intertrappean beds, particularly,
        subsurface sections of the southeast coast, west coast, and
        the outcrops of Gurmatkal yielded fossils, which favour a
        slightly younger age (Early Palaeocene). It is thus concluded
        that the Deccan volcanism was initiated in the Late Maastrichtian
        and continued up to Early Palaeocene, extending over a period
        of 4 Ma.

                                *       *       *


Michel Chartier
chartiem@ere.umontreal.ca


>