Santonian Working Group
Chairman: Dr. Marcos A. Lamolda
Circular 6th
To all members
Therewith a copy of a extended report of our meeting at Brussels. It has been enlarged with some recent references and your comments, which I truly acknowledge.
Recognition of the Coniacian-Santonian Boundary look fine with good correlation of macro- and microfossil evidences. But sub-stages need a better understanding of taxa ranges and correlation, through different biogeographic realms, to achieve a valuable Santonian subdivision.
I have visited with Prof. Rory Mortimore the Seaford Head section. Santonian rocks are well exposed and fossil occurrences are easely checked. I suggest the Working Group visit and study three proposed localities for the Coniancian-Santonian Boundary during next three or four years. I think it is convenient for an appropriate decission on boundary stratotype.
As some members did not attend Brussels meeting, I ask all of you let me know your present opinions and comments on proposals. Please, remark when appropriate which points you support, which point you refuse, and any suggestion, correction, etc., in the enclosed copy of this circular and send me not later than February 5th.
I am expecting for your news,
Lejona, January 9th, 1996
Selected marker for the Coniacian-Santonian boundary
YES NO FAD's Inoceramus (Cladoceramus) undulatoplicatus
YES NO Secondary marker: FAD's Sigalia carpatica
If you disagree, please give details on your opinion (add other page if necessary):
Boundary Stratotype Section. We have selected three candidates:
1) Olazagutía Quarry (Navarra, Spain). Prof. Lamolda would collate data and report to the Chairman.
2) Seaford Head (Sussex, England). Dr. Mortimore and Mr. Wood would collate data and report to the Chairman.
3) Ten Mile Creek (Dallas, Texas). Prof. Kauffman and Dr. Gale would collate data and report to the Chairman.
I agree/disagree
I also propose the section............................................................................................................ (please, send report)
I will/will not attend Field-trip(s) to proposed Boundary stratotype localities
Sub-stages of the Santonian Stage. After discussion was made this motion:
1) The WG favoured a 3 fold division of the Santonian
2) Formal proposals are premature at present
3) A possible datum for the base of the Middle Santonian is the extinction point of Inoceramus (C.) undulatoplicatus.
4) A possible datum for the base of the Upper Santonian is the first occurrence of Uintacrinus socialis.
I agree/disagree (if you disagree or have other proposals, please send a report)
Other suggestions:
Your name: Date:
Marcos A. Lamolda |