Detailed biostratigraphy of the Santonian/Campanian boundary interval in Northern Israel

One of the best continuous and fossiliferous Late Santonian-Early Campanian successions in Israel is the approximately 6m thick Kabri section in northern Israel. Its chalky marls were deposited in an outer shelf to upper slope environment with minor depth fluctuations. This Santonian/Campanian interval was studied examining calcareous nannoplankton, palynomorphs, ostracods and benthonic and planktonic foraminifera. The planktonic foraminiferal Dicarinella asymetrica - Globotruncanita elevata concurrent range zone was first observed in Israel in the Kabri section. The first occurrence of Aspidolithus parcus parcus herein is characterized by small specimens, difficult to determine by light microscopy. The lower boundary of the Campanian in this sequence was defined by the first occurrence of G. elevata, in accordance with the ammonite stage definition. This datum line nearly coincides with the first occurrence of the nannofossil marker A. parcus parcus and with the base of the Leguminocythereis dorsocostata (S-4) ostracod zone, both slightly above the foraminiferal boundary.

The Lucianorhahdus cayeuxii (CC 16) Zone is the lowermost nannofossil zone in our section. Here, nannofossils are common and moderately or poorly preserved, showing some etching and recrystallization. The CC 16 Zone was defined by Sissingh (1977) as the interval from the first occurrence (FO) ofL. cayeu.r.ii to the regular FO of Ca1culite.s ohscurus. Only the uppermost part of this zone, (Late Santonian) is represented in the Kabri section. This assemblage is overlain by the Calculites ohscurus (CC 17) Zone. The samples contain abundant coccoliths. The preservation of the fossils is, in general, poor to moderate, some etching or slight recrystallization is noted. The CC 17 Zone is defined as the interval between the regular FO of C. ohscurus to the FO of Aspidolithus parcus and as Late Santonian-earliest Campanian in age (Sissingh, 1977;Perch-Nielsen, 1985). The occurrence of C . obscurus in the Late Santonian (Sissingh, 1977, p.52;Doeven, 1983, pp.13, 24;but Campanian according to Perch-Nielsen, 1985, p.362) is confirmed also in the Kabri section. There, C . obscurus (PI.1, fig.15) occurs rarely, although it is present in most layers above sample AF 754. The dominating species in this zone are W. harnesae, E. eximius, P. cretacea and Thoracosphaera spp. These are accompanied by rare to few occurrences of A . furtivus, H. cuneatus, M . furcatus, Eprolithus floralis and Calculites ovalis. All these species are known in Santonian sediments from various parts of the world.
The Aspidolithus parcus (CC 18) Zone is the uppermost zone in our section. The samples contain abundant nannofossils and sometimes form nanno-ooze. The preservation of the fossils is usually good, although some etching and recrystallization is observed, especially in the lower part of this zone. The CC 18 Zone is defined as the interval between the FO of A . parcus and the LO of M. furcatus and as Early (not earliest) Campanian in age (Sissingh, 1977;Perch-Nielsen, 1979. Due to the lack of upper successive samples, its upper boundary in the Kabri section is not clear enough to accurately mark the LO of M . furcatus. The assemblage in our samples is dominated by W. harnesae, Zygodiscus spp., Thoracosphaera spp., E. e-t-imius and L. carniolensis. These fossils are accompanied among others by Arkhangelskiella specillata (PI.1, figs 7, 14), A . cymbijormis, A . furtivus, B , dentutu, R. anthophorus, A . parcus espansus (PI. I . fig.3), H . cuneatus, M . furcatus, Lithastrinus grilli (PI.1, figs 9, 17) and C. ohscurus. The most indicative Campanian nannofossil species Aspidolithus parcus parcus was found from sample AF 757 upwards. The specimens of this form in the lowest samples of the CC 18 Zone (AF 757-758) are about 5-6 microns in size (PI. I , figs 4-5) and difficult to determine by light microscopy. They attain an average size of 10-12 microns in the upper samples (e.g. AF 772; PI. I , figs 6, 13). thus confirming the evolutionary trend, as suggested by Lauer (1975). This species must be included in the genus Aspidolithus Noel arid not in Broinsonia Bukry. The latter genus, designated by the type-species B. dentutu (Bukry, 1969, P1.2, figs 1-3;Hattner & Wise, 1980, PIS, figs 6-8). has a tapering central cross and lacks the round pores in the central area (see PI. I , fig. 1 ). and is not appropriate for species such as purut.7. In the uppermost sample AF 774, forms already close to A . parc.rrs constrictus could be observed. Their subspecific designation. however, remains questionable. since their central area is somewhat wider (b/a ratio around 1.0, see Hattner et nl.. 1980: Wise, 1983. Samples higher up might provide more information on the evolutionary lineage of the As~idolithits-Br.oi~~.~orii~/ group along the Santonian-Campanian boundary interval (see suggestions and discussions in Lauer. 1975: Perch-Nielsen, 1979:    , 1980;Crux, 1982;Wise, 1983;Stradner & Steinmetz, 1984). Marthasterites furcatus (P1.1, figs 11-12) is also an important species, its LO is known to occur in the early Campanian, somewhat above the FO of A. parcus parcus. In our section, M . furcatus is found up to sample A F 772. Hexalithus gardetae, another indicative form for the Campanian stage (Perch-Nielsen, 1985, p.390) is found in s a m p l e A F 7 7 1 . Large specimens of Helicolithus (=Chiustozygusj cuneatus (Lyu'leva) Cepek & Hay (PI. I, fig. 16) are rare in the Kabri section, but occur together with A . parcus parcus. T h e species differs from Eiffellithus traheculatus (Gorka, 1957) of Albian-Maastrichtian age (Thierstein, 1976, p.339) by its larger form a n d the symmetrical cross. These forms usually accompany the Santonian nannofossil assemblages in central and southern Israel (Gvirtzman et ul. 1985(Gvirtzman et ul. , 1989

OSTRACODS
Ostracods are generally common to rare in the samples, only sample A F 754 yields abundant ostracods. The assemblages are relatively highly diversified and twenty-seven species, belonging to eighteen genera, were observed ( Fig.3; for taxonomy see Honigstein, 1984). The section can be subdivided into three parts: the S-3 ostracod Zone (AF 751), the S-3b Subzone (AF 753-757) and the S-4 Zone (AF 758-774). The exclusively Santonian species Cythereis cretaria occurs only in the lowermost sample and indicates, together with Limhurgina miarensis and Cythereis cretaria dorsocauduta, the L. rniarensis (S-3) a s s e m b l a g e zone of L a t e Santonian a g e (Honigstein, 1984;Honigstein et a/., 1987). Occurring above this level and upwards are, among other species, Cytherella aff. eliotti, Krithe solomoni (P1.2, fig. 14) and Bythocypris aff. howchiniana, which appear in the subzone S-3b of the hitherto undefined Santonian-Campanian boundary interval (see references above).
T h e s a m p l e s A F 7 5 8 -7 7 4 belong to the overlying Leguminocythereis dorsocostata (S-4) assemblage zone. The lower boundary of this zone in the Kabri section is defined by the FO of P. campania. Juvenile forms of this species were found from sample AF 758 upwards, already showing the development of subanterior ribs, typical for P. campania (Honigstein, 1984, p.17). Adult forms of P. campania (P1.2, fig.12) occur together with L. dorsocostata (P1.2, fig.11) from sample A F 76.5 and upwards. Eucytherura tetracornis (P1.2, fig.13) ranges in this section from AF 758 and upwards within the S-4 Zone.

FORAMINIFERA
The foraminifera1 assemblage composition in the Kabri marl section was first investigated by Baida (1964). Most of the species determined are benthonic foraminifera and several of them were left in open nomenclature. Only five planktonic foraminifera1 species were recognized in the section. The Early Campanian age determination (Baida, 1964) was based only on general ranges of the fauna and should be re-evaluated.
although slightly decreasing in abundance in the upper part of the section where the benthonic species are more frequent and the faunas are rather poorly preserved. Most of the planktonic species belong to the genera GlohiRerinelloides, Hedhergella and Heterohelix (Fig.4). Globotrucanids are diversified and common, but represent only a minor component of the planktonic foraminiferal assemblage. Twenty Globotruncanidae species were identified throughout the section, the maximal diversity of this family is observed in its middle part (fifteen species, sample AF 767). The ranges of Globotruncanidae species enable a division of the Kabri Marl section into three planktonic foraminiferal zones which are in accord with the Tethyan zonation (Kuhry, 1970;Barr, 1972;Wonders, 1980;Dowsett, 1984;Robaszynski et a/.. 1984). The lower Dicarinella asyrnetrica interval zone (Late Santonian) is determined by its index fossil (P1.2, figs 5-6) as from the base of the succession up to the FO of Glohotluncanita ele\.trru (P1.2, figs 8-9) at sample AF 755. From this sample up to sample AF 768, D. asyrnetriru and G. rle~nra occur together and define the D . a.7ymrtric.a -G. Elei.ata concurrent range zone. This zone was hitherto not observed in Israel (Reiss et al., 1985;Almogi-Labin et a/., 1986;Honigstein et a/., 1987). The overlying G. elevata interval zone (Early Campanian) starts above the extinction of D . asymutric.~ and ranges from sample AF 769 to the top of the section.        . . . . I1