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Samples from Upper Jurassic and Lower Cretaceous sediments at Site 511 were analyzed for palynomorphs. Three palynological assemblages were identified: Upper Jurassic (presumably Tithonian), Neocomian-Aptian, and lower Albian. These were correlated to synchronous assemblages in Argentina, South Africa, and Australia and were compared with Jurassic palynoassemblages from Hole 330, Leg 36. INTRODUCTION At Site 511, on the Falkland Plateau (western part of the Maurice Ewing Bank), Upper Jurassic and Lower Cretaceous sediments were penetrated by Hole 511, drilled to a depth of 632 meters some 10 km from Site 330 (Leg 36). Within the Jurassic-Lower Cretaceous interval, two lithological units (Units 5 and Unit 6) were identified. The upper unit (Unit 5) is composed of calcareous claystones. Their oxidation state did not favor the preservation of organic matter: the sediments contain no spores, pollen, dinoflagellate cysts, or plant detritus. The lower unit (Unit 6) is composed of black shales containing 1.7-4.1% organic carbon. In this unit, only 47 of all samples taken contained spores, pollen, dinoflagellate cysts, and great amounts of plant detritus. The samples were treated with hydrochloric acid, potassium sodium hydroxide, hydrofluoric acid, and cadmium liquid. The results of the palynological analysis are summarized in Table 1, which shows the percentage of spores and pollen. Figure 1 shows the stratigraphic distribution of the most characteristic species and genera. Photographs in Plates 1-15 were made with a Biolam microscope and a MNF-12 microphotographic device. DISTRIBUTION OF SPORES AND POLLEN IN UPPER JURASSIC AND LOWER CRETACEOUS SEDIMENTS AT SITE 511; AGE OF PALYNOASSEMBLAGES Organic remains of plant origin in the interval between 498 and 632 meters (Unit 6, Cores 70-56) consisted of plant detritus, spores, pollen, and dinoflagellate cysts. The last were not examined in this study. Plant detritus in Cores 70-59 is in the form of amorphous sapropelic material and fragments of cuticles and tracheids belonging to terrestrial plants. The distribution of pollen and spores in this interval is variable. They are abundant in Cores 70-68 and 63-60 but not numerous in Cores 6764 and 59. In some samples from the uppermost parts of Ludwig, W. J., Krasheninnikov, V. A., et al., Init. Repts. DSDP, 71: Washington (U.S. Govt. Printing Office). this interval (Cores 63, 61, 59), amorphous detritus is coagulated into rounded yellow brown aggregates with an admixture of pyrite. Traces of pyrite are seen on the surfaces of spores and pollen. The available sapropelic material enables us to assume that black shales in this interval were formed under anaerobic conditions. The uneven distribution of pollen and spores suggests an alternation of anaerobic conditions with slightly oxidizing environments. However, low abundances of spores can be due to unfavorable climatic conditions for ferns on the nearby land. Amorphous sapropelic material disappears at the beginning of Core 58. In Sample 511-58-3, 53-55 cm, the plant detritus consists of large, bright orange, cuticular remains. The content and diversity of fern spores sharply increase. From Sample 511-58-2, 142-144 cm to Sample 511-56-4, 142144 cm the plant detritus contains fragments of middlesized cuticles and tracheids, brown to black in color, with an admixture of crushed micrinitic material. Disappearance of sapropelic material may denote the beginning of oxidizing processes, and the admixture of micrinitic material may suggest a certain remoteness from a source area. Diverse and numerous fern spores lead us to assume that climatic conditions for the existence of ferns were favorable on the nearby land. The palynological analysis allowed us to distinguish three assemblages within the interval from 495 to 632 meters. Assemblage I Assemblage I was identified in the interval from 632 to 555 meters (Cores 70-63). Of 31 samples analyzed, 18 contained spores and pollen. The assemblage abounds in gymnosperm pollen in which Classopollis predominates (45.5-78%) and Vitreisporites pallidus (7.5-38%) is abundant. Bisaccate and trisaccate conifer pollen and pollen of the genus Callialasporites (C. dampieri, C. trilobatus, C. turbatus, C. segmentatus) are always present. Less frequent is monosaccate conifer pollen (Monosaccites sp. 1), Sulcosaccispora sp., and Araucariacites australis. Spores are not numerous (2.0-8%) and are represented mostly by Antulsporites saevus, A. varigranulatus, Converrucosi-

Palynological Study of Upper Jurassic and Lower Cretaceous Sediments, Site 511, Deep Sea Drilling Project Leg 71 (Falkland Plateau)