The Microfossil Gap

[N.MacLeod@xxxxxxxxx (N. MacLeod)]

As a follow-on to my previous comment, I understand and agree with
Marshall's point about the problems of estimating confidence infervals when
the sampling of a core is discontinuous.  In those instances, you don't
have a sufficient handle on the gap size distribution.  However, gaps
appear in the occurrence distribution of most microfossil taxa even when
the core is sampled continuously.  In those instances I think realistic
stratigraphic confidence intervals can be calculated for microfossil data
provided you have an independently justified chronostratigraphic model for
the entire sequence and can meet all the other assumptions outlined in the
Sadler & Strauss and Marshall papers.

Norm MacLeod


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Norman MacLeod
Senior Research Fellow
N.MacLeod@nhm.ac.uk (Internet)
N.MacLeod@uk.ac.nhm (Janet)

Address: Dept. of Palaeontology, The Natural History Museum,
                     Cromwell Road, London, SW7 5BD

Office Phone: 071-938-9006
Dept. FAX:  071-938-9277
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