M. HAJOS 34.5. THE MEDITERRANEAN DIATOMS Marta Hajos, Hungarian Geological Institute, Budapest, Hungary INTRODUCTION species. The relevant information has been obtained from the references cited at the end of this chapter and from Ten washed samples taken at eight levels from the drill investigations of Hungarian fossiliferous localities. cores of the Mediterranean expedition of the Deep Sea The 175 taxa investigated belong primarily to the phyla Drilling Project were sent for study to the present writer by Chrysophyta and Bacillariophyta, and are accompanied in Paulian Dumitrica of the Geological Institute, Bucharest, subordinate numbers by representatives of Phytolitharia, Rumania. He had found these samples to be the richest Acritarcha, Radiolaria and Porifera. diatom-bearing sediments both in terms of species and The paleoecological assignments shown in Table 1 and individuals. the complete floral spectrum allow three paleo-ecological Two samples from Core 13 of Site 124—Balearic Rise1 divisions, representing three areas of the Mediterranean and were selected near levels of finely laminated dolomitic three different sedimentary facies, to be distinguished. marls with dark green to black interbeds. This dolomitic unit is part of the evaporite series cored in the deep Balearic Division 1 — Siliceous Dolomitic Marls of Site 124 Basin. All six samples from Sites 127 and 128 in the 2 Hellenic Trench of the Ionian Basin are from layers of The sediments of the two samples from Site 124 dark sapropelitic ooze, where the siliceous microfauna is (124-13-2, 89-90 cm and 124-13-2, 127-129 cm) were particularly abundant. The remaining two samples are from apparently deposited under the same ecological conditions. Site 130 on the Mediterranean Ridge in the Levantine 3 The predominantly littoral planktonic forms are accom- Basin , and represent the siliceous microfossil content of panied by brackish water, and even freshwater, euryhaline, dark blue black terrigenous clays believed to have been benthonic, and epiphytic species in considerable numbers. transported to this site from the Nile Cone (see Conclusions of Chapters 11, 25.2, and 35 of this volume). Taxa characteristic of stagnant brackish waters and landlocked salinas and lagoons are present in such great Procedures numbers as to suggest reduced salinity, shallow water The author's study has been restricted to investigating depth, and a landlocked, stagnant sedimentary environ- the available washed samples. It must be taken into ment. As for salinity, it may have been upper brackish (0 to consideration that because a sizable portion of the flora 5°/oo) or possibly lower brackish (5 to 20°/oo). Since the may have been lost in sample preparation, the assemblages species indicative of low salinity are benthonic, they must reported here may not be representative of the original be mutochthonous rather than allochthonous. The littoral thanatocoenosis, nor of the original depositional environ- brackish water forms living in salinas and stagnant waters ment. The investigations were carried out on strewn slides found in these samples include: mounted in Caedex with the aid of an Opton binocular photomicroscope; the documented taxa were photographed Achnanthes brevipes (epiphytic) with the same instrument. Campylodiscus clypeus var. bicostata (benthonic) Sali- nity: 0-5%o) Cocconeis pediculus (epiphytic) DISCUSSION Diploneis didyma (benthonic). Salinity: 5-20°/QO. In the plates enclosed herewith (Plates 1-9) only a few Diploneis ovalis. Salinity: 0-5°/oo characteristic species of the rich floral assemblages are Epithemia Sorex (epiphytic) shown. The complete floral list is shown on Table 1, with Grammatophora angulosa var. islandica (epiphytic). indication of the characteristic ecologies and ranges of the River-mouth-dwelling form Mastogloia brauni (epiphytic). Frequent Mastogloia elliptica var. dansei (epiphytic). Frequent Mastigloia sp. I, sp. II, sp. HI (epiphytic). Frequent Navicula humerosa. River-mouth-dwelling form ^ite 124, Latitude: 38° 52.4'N; Longitude: 04° 59.7'E; water Nitzschia granulata (benthonic) depth 2726 meters; Core 13 at 417 meters below the sea floor. Nitzschia parvula 2Site 127, Latitude: 35° 43.9'N, Longitude: 22° 29.8'E; water Rhopalodia gibbetula var. Van Heurckii depth 4654 meters; Core 5 at 101 meters and Core 14 at 380 Rhopalodia musculus. River-mouth-dwelling form meters below the sea floor, respectively. Surirella striatula. Salinity: 5-20°/oo Site 128, Latitude: 35° 42.6'N; Longitude: 22° 28.1'E; water depth 4640 meters; Core 3 at 88 meters, Core 10 at 418 meters, and Core 11 at 474 meters below the sea floor, respectively. The presence of freshwater and river-mouth-dwelling 3Site 130, Latitude: 33° 36.3'N; Longitude: 27° 52.0'E; water species indicates a considerable influx of fresh waters into a depth 2979 meters; Core 3 at 86 meters and Core 4 at 150 meters landlocked basin at the time of formation of the dolomitic below the sea floor, respectively. marls. These species include: 944 34.5. MEDITERRANEAN DIATOMS TABLE 1 The Distribution of Siliceous Microfossils in the Samples Studied Locality m UI m m UI UI c O c ε c 0 O O I 9 7 2 OS 4 f= 15 : s 1 - 0 ü 3 0 1 OO 27- 6-1 9-9 44- -10 2cie 59-6 148 ex co r~ on ?1 CO m <T> co m <O *"? ò ò i-H u u ^H 10 •H u u co >—' "―1 en •43 P- r- 00 OO OO OO ò 0 Species X Ecologiesa c l CN (N CN <N (N (S CO Ages W CHRYSOPHYTA ARCHAEOMONADALES: Archaeomonadapsis cfr. lagenula Defl. + M,p X Upper-Eocene, — ? Archaeomonas califomica Defl. + M,p X X Miocene inconspicua Defl. + M,p X X Upp.-Cretaceous—Pliocene faponica Defl. + M,p X X X Miocene mangini Defl. + M,p X Upp.-Cret.-Miocene? melo Defl. + M,p X X Miocene sp. + M,p X IMicrampulla sp. M,p X SILICOFLA GELLALES: Cannopilus cfr. sphaericus Gemein. + M,p X Miocene — ? Dictyocha fibula Ehr. M,p X X X X Upp.-Cret. — Recent speculum Ehr. M,p X X X X X X Eocene - Recent Mesocena binonaria Ehr. + M,p X Fossil Guano (Chile) Mesocena elliptica (Ehr.) Ehr. var. pentagona Bachm. & Teh. + M,p X Miocene elliptica (Ehr.) Ehr. var. quadrangula Bachm. & Teh. + M,p X X Miocene — ? polymorpha Lemm. var. bioctonaria (Ehr.) Lemm. M,p X Miocene - Recent EBRIIDALES: Hermesinum cfr. adriaticum Zach. M,p X X Miocene — Recent BA CILLARIOPHYTA: Achnanthes brevipes Ag. B,e,l,s © Miocene - Recent fimbriata (Grun.) Ross M,B X Miocene — Recent, Med. sp. X Recent? Actinocyclus octonarius Ehr. M,B,n,l,p X X Miocene — Recent octonarius Ehr. var. crassa (W. Sm.) Hust. M,B,p,n,l X Miocene — Recent octonarius Ehr. var. minuta (Pant.) Hajós M,B,l,p,eu. X Miocene - Recent, Med. octonarius Ehr. var. tenella (Brëb.) Hajbs M,B,p,l,eu X X X Miocene - Recent, Med. Actinoptychus reinholdii Hajbs + M,p X Neogene — ? senarius (Ehr.) Ehr. M,n,l,p,st X X Upp.-Eocene — Recent, Med. senarius (Ehr.) Ehr. var. minor (A. Cl.) Hajbs + M,n,l,p,st X Upp .-Eocene — Pleistocene Amphora cfr. angusta (Greg.) Cl. M X Miocene — Recent holsatica Pant. B Miocene - Recent minuta Pant. var. interrupta Hajbs + B ® 0 Miocene - ? proteus Greg. M,l,b X Miocene —Recent, Med. sp. X Asterionellz sp. M X Asteromphalus robustus Castr. M,o,p,sh X X X Miocene — Recent, Med. comosum Pavillard M,p,n,st X Fossil ? - Recent, Med. sp. M,p X X clypeus Ehr. var. bicostata (W. Sm.) Hust. M,B,l,s,b <s> Fossil ? - Recent echeneis Ehr. B,l,s,b <s> Pliocene — Recent Campylosira sp. M,p X Diatom Zone 945 P. DUMITRICA TABLE 1 — Continued Locality m m m m c c c m 9 m m c 0 7 c 9 c c m 0 2 0 s c 8 89-9 127-12 5- 148-15 59-6 144-14 ; ; ; ; ; ; 136-13 97-10 Specie ; ; t C C C C 4 3 Extinc Ecologies Ages Species 124-13-2 124-13-2 127-5-6 127-14-4 128-3-6 128-10-3 128-10-3 128-11-3 130- 130- Chaetoceros gastridium Ehr. M,p,st X Fossil Guana (Peru) — Recent louden Ralfs M,p,n X Pleistocene — Recent sp. I M,p X sp. II M,p X sp. Ill M,p X XX sp. IV M,p X sp. V M,p X sp. VI M,p X Cocconeis britannica Naeg. M,l,e X Miocene — Recent, Med. costata Greg. M,l,e,b X Miocene — Recent, Med. ornata Greg. var. signata Perag. M,l,e,b,st. X Fossil ? Recent pediculus Ehr. B,t,e,l,s Fossil ? Recent placentula Ehr. var. klinoraphis Geitl. F,e • Pliocene — Recent pseudomarginata Greg. M,l,e,b X Miocene — Recent scutellum Ehr. M,B,e,s,b,n X X Lower Miocene — Recent sp. I e X sp. II e X ?Cocconeis sp. e X X Coscinodiscus apiculatus Ehr. var. ambigua Grun. M,p XX Miocene — Recent curvatulus Grun. M,o,n,p X Miocene — Recent curvatulus Grun. var. arcuata Hajbs M,p X Miocene — ? X curvatulus Grun. var. macropunctata Hajbs M,p XX Miocene — ? X curvatulus Grun. var. minor (Ehr.) Grun. M,p X Miocene - Recent divisus Grun. M,o,n,l,p X Miocene — Recent X excentricus Ehr. X X Miocene — Recent B,B,p,r X X excentricus Ehr. var. macropora Grun. M,B,p,r X Miocene — Recent globosus Hajbs X Miocene — ? M,p XX hustedtii Jousë M,p Paleocene-Miocene — ? kützingii A. Schm. 0 M,p,l X Miocene — Recent ? lineatus Ehr. M,o,n,p,r 0 Miocene — Recent marginatus Ehr.