Anexo una comunicación de mi querido profesor y tutor, Laurence L. Sloss, fallecido en Evanston el 2 de noviembre de 1996, porque la misma enfoca uno de los grandes problemas estratigráficos del Cretácico de Venezuela y porque la nota mantiene su vigencia hoy en día.
W. Scherer, 5 de mayo 1997.
NORTHWESTERN UNIVERSITY October 10, 1994
Dr. Wolfgang Scherer
INTEVEP
Friend Wolfgang
Sincere apologies for being absent-without-leave when you visited Locy Hall on October 6! ( Older people have difficulties with short-term memory retention.)
I was looking forward to talking with you about the Venezuelan Cretaceous; the outcrop succesion has become a cause célébre among sequence-stratigraphers -- specifically, between the Exxonians and Pindel1 & associates. At the AAPG meeting (Denver, June) there was an SEPM go-around featuring the latest Vail +CRSN + ELF, etc., findings from the Cretaceous of the Vercours (sp.?) Plateau (S.E.'n France; many "third-order" sequences) and parallel studies by Pindell et alia from the Colombian border across most of Venezuela ( many fewer recognizable sequences). It is an act of faith that such sequences are created by eustatic events and are therefore of global range - - certainly, during the opening of the Atlantic, southern Europe and northern South America were intercommunicating regions of ancient Tethys, both lay adjacent to the inboard (or proximal) flank of a passive margin, and both should have shared the same history of sea-level oscillation.
The stratigraphic community is thus presented with a choice among difficult alternatives:- a) the groups use different criteria in identifying intersequence unconformities (downlap surfaces, flooding surfaces, etc. ) or , b) there are more unconformities in France as a result of a higher frequency of regional tectonic uplift/downwarp or, c) there are gaps in the reported Venezuelan stratigraphic record because of inadequate observation or because the record is truncated by post-Cretaceous deformation.
During the discussion session following the formal papers it was noted that there were new data from recent deep drilling in the Maracalbo Basin and that these findings tended to corroborate the Pindellian view from the outcrop ( I think). In any case, you and INTEVEP could be of great service by letting us in on what you have learned from outcrop and subsurface studies that may have a very serious bearing on this continuing controversy. How about a contribution to the SEPM sessions to be held in Houston in March? I would be happy to cooperate in any useful manner ( i.e., by leaning on the program committee, or whatever).
Let me know what you think, preferably by an old-fashioned letter or, if you must, by Email. Messages via Bob Speed (speed@ earth nwu.edu) reach the box in our joint outer office.
Cordially, L.L. Sloss
Department of Geological Sciences Locy Hall Evanston, Illinois 60208-2150 Telephone (708) 491-3238 Facsimile (708) 491-8060
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