PALEOCEANOGRAPHY, VOL. 8, NO. 5, PAGES 671-690, OCTOBER 1993 LATE CRETACEOUS UPWELLING SYSTEM ALONG THE SOUTHERN TETHYS MARGIN (ISRAEL): INTERRELATIONSHIP BETWEEN PRODUCTIVITY, BOTTOM WATER ENVIRONMENTS, AND ORGANIC MATTER PRESERVATION Ahuva Almogi-Labinand AmosBein Geological Survey of Israel, Jerusalem Eytan Sass Department of Geology, HebrewUniversity, Jerusalem Abstract. Organic-rich Upper Cretaceous sequences in Israel were deposited in an extensive, highlyproduc- tive upwelling-linked system which prevailed along the southern Tethys margin,andlasted for •- 19 m.y. (Santonian to late Maastrichtian). An understanding of the spatial andtemporal characteristics of this system wasgained through detailed paleontological and geochemical analyses of subsurface sequences in two basins in Israel, representing an outer(Shefela) andan inner (Zin) facies belt. The nature of the upwelling system, andits effect on the sedimentary record, is relatedto two basicenvironmental parameters, namely paleoproductivity intensity andoxygen levels at the bottom.The assessment of these parameters andtheir interrelationship hasbeen performed through the development of paleontological (foraminiferal) criteria, which are independent of the organic mattercontent. Followingthe establishment of these criteria,it is concluded that the productivity reached its maximum intensity during the late Campanian, which wasalso the time of most notable differentiation between the center of the upwelling system in the innerbelt andthe less intense conditions in the outer basin. This distribution is expressed in variedlithology (organic-rich carbonates, phosphorites, andsiliceous rocks) at the core of upwelling anda uniformlithology(organic-rich Copyright1993 by the American Geophysical Union Papernumber93PA02197. 0883-8305/93/93PA-02197510.00 671 carbonates) at the margin of this system. The uniform lithology of the Maastrichtian in bothbasins, composed of organic-rich carbonates, is ascribed to a gradual weakening of productivity. The bottom conditions in the innerbelt duringthe late Campanian (the time of maximum surface productivity) were nearanoxic, changing to more aerated (dysaerobic) conditions during the early Maastrichtian. In the outerbelt a more aerated bottom (dysaerobic) prevailed throughout the late Campanian to late Maastrichtian. The elevated organic matter content in both basins reflects the overall environment of highproductivity; its actual variations, however, seem to be unrelated to changes in surface productivity andbottom oxygen levels. Introduction Organic-rich carbonates andphosphorires are widely distributed along the southern margin of the former Tethys ocean andbelong to the widespread Upper Cretaceous-Eocene phosphate belt that extends from South Americathrough North Africa and as far as the Arabian craton. Theserocksoccurin Upper Cretaceous sequences together with cherts andporcellanites. A similarlithological association is common in both Recentand fossil sediments related to coastal upwelling systems, such asthose off southwest Africa [Bremner, 1983; Calvert and Price, 1983], the Miocene Monterey formation in Northwest America [Pisciottoand Garrison,1981], Quaternary offshore andmiddle Eocene onshore Peru [Dunbaret al., 1990; Garrison andKastner, 1990], the Upper Cretaceous La Luna and Villeta formations in South America [Macellari and De Vries, 1987], andthe Upper Cretaceous andRecent