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From: William Berggren <wberggren@whoi.edu>
Date: 17 September 2004 18:51:04 GMT+00:00
To: mh300@cam.ac.uk
Subject: IGC TIME SCALE
MARTIN
KEN MILLER FORWARDED (AS DID BRIAN MCGOWRAN) YOUR RECENT EMAIL REGARDING THE GRADSTEIN TIME SCALE. I SEEM NOT TO HAVE BEEN ON YOUR MAILING LIST? I MANAGED TO SPEAK WITH FELIX GRADSTEIN ABOUT THIS PAPER AND THE FORTHCOMING CAMBRIDGE BOOK WHICH WAS DISPLAYED AT CU BOOTH IN EXHIBTION HALL AT IGC IN FLORENCE.
I WILL ENDEAVOR TO ANSWER SOME OF YOUR QUERIES AND ASK YOU TO FORWARD THEM TO YOUR MAILING LIST ON MY BEHALF.
GENERAL IMPRESSION (FOCUSING ON CENOZOIC ONLY): INTERESTING COMPILATION OF A LARGE AMOUNT OF DATA WITH LITTLE OR NO CREDIT GIVEN TO SOURCE(S). WHO COMPILES THE BIOSTRATIGRAPHIC DATA AND INTEGRATES IT WITH THE GEOCHRONOLOGY AND/OR MAGNETOSTRATIGRAPHY? HOW IS THE READER TO KNOW/EVALUATE THE QUALITY CONTROL APPLIED TO THESE COMPILATIONS? NONE OF THE MEMBERS OF BKSA95 WERE EVER CONTACTED TO CONTRIBUTE/EVALUATE TO THIS WORK! SIMPLY APPLYING MATHEMATICAL AGORITHMS TO EXTANT QUANTITATIVE DATA SETS ON PARTS OF THE IMBS DOES NOT CONSTIUTE A GEOLOGIC TIME SCALE IN MY OPINION.
THAT SAID LET'S TAKE A CLOSER LOOK AT PARTICULARS:
1. THE QUERY ABOUT DISCREPANCIES BETWEEN LOWER MIOCENE ZONE M3/N6 IN BKSA95 AND GOSBL04 (~1.5 MY VS 0.1-0.2MY, RESPECTIVELY): THE BASE OF THIS ZONE IS TYHE FAD OF GLOBIGERINATELLA INSUETA, A MORPHOLOGICALLY DISTINCT, BUT BIOGEOGRAPHICALLY RESTRICTED. TAXON WHICH LACKED A MAGNETOSTRATIGRAPHIC CALIBRATION IN 1995 (SEE BKSA95: 159, 174, TABLE 11, ITEM 10). I CAN ONLY SURMISE THAT IN THE ELAPSED PERIOD SINCE 1995 AND THE PREPARATION OF THIS NEW SCALE THAT A MAGNETIC CALIBRATION HAS BEEN ACHIEVED FOR THIS DATUM. BUT LACKING THIS INFORMATION AT THIS TIME (AND I AM NOT SURE THIS TYPE OF COMPILATION WILL BE AVAILABLE IN THE FORTHCOMING CU BOOK), IT IS NOT POSSIBLE TO PROVIDE A SUITABLE EXPLANATION FOR THE DISCREPANCY.
2. THE QUERY OVER DISCREPANCY WITHIN THE NEW SCALE OF THE BASE BURDIGALIAN AT TOP C6AN (P. 86) VS C6AN.1R (P.97, FIG. 5A) WITH IDENTICAL AGE OF 20.43 MA CAN ONLY BE EXPLAINED AS LAPSUS CALAMI IN THE COURSE OF PREPARING THE FIGURE VS TEXT. FORGIVENESS IS IN ORDER. WHO HAS NOT COMMITTED SUCH AN ERROR! THAT IS WHAT ERRATA SECTIONS ARE FOR!
3. I HAVE A RATHER MORE POINTED CRITIQUE TO MAKE OF THE AUTHORS' FAILURE TO CITE (CORRECTLY) THE SOURCE OF THE DATA FOR THE NEOGENE PORTION OF THEIR TIME SCALE. NOTE THAT BKSA95 IS NOT CITED IN THE REFERENCES, ALTHOUGH ON P. 99, LINE 12 BERGGREN ET Al, 1995a, IS CITED. THE NEOGENE TIME SCALE WAS PRESENTED IN BKSA95 AND THE PLIOCENE-PLEISTOCENE PORTION TREATED IN GREATER DETAIL IN BERGGREN 1995a. BOTH PAPERS INCORPORATED THE APTS CHRONOLOGY OF SHACKLETON AND HILGEN IN THE CONSTRUCTION OF THE (LATEST) NEOGENE CHRONOLOGY AND BOTH INCORPORATED A DETAILED LIST OF INTEGRATED MAGNETOBIOSTRATIGRAPHIC CORREL.ATIONS ON WHICH THE TIME SCALES OF 1995 (AND THAT OF GOSBL04) HAVE BEEN CONSTRUCTED.
--
Bill Berggren
Department of Geology and Geophysics
Woods Hole Oceanographic Institution
Woods Hole, MA 02543
tel: 508-548-1400 X2593 (operator assisted) or 508-289-2593 (direct)
fax: 508-457-2187
email: wberggren@mail.whoi.edu
Department of Geological Sciences
Rutgers, The State University of New Jersey
Wright Laboratory, Busch Campus
610 Taylor Road
Piscataway, NJ 08854-8066
tel: 732-445-8523
fax: 732-445-3344
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