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31. FROM THE NORWEGIAN , LEG 38 OF THE DEEP SEA DRILLING PROJECT Kjell R. Bj^rklund, Geological Institute Department B., University of Bergen, 5014-Bergen-University, Norway

INTRODUCTION North Atlantic , Benson (1972) was able to use the established radiolarian stratigraphy for an age The high latitudes of the were first determination of the sediments. Thus, one of the main visited by D/V Glomar Challenger in 1974, on Leg 38 of objectives of this paper was to search out the radio- the Deep Sea Drilling Project, to the . larian stratigraphy, and see if the already established Seventeen sites were selected, and 17 holes were drilled zonation from lower latitudes could be used with faunal during this leg (Figure 1, see Table 1 in Chapter 1, this assemblages recovered from the Norwegian Sea. volume) Based on reports from Russian workers, Lipman For radiolarian studies, the Norwegian Sea is a virgin (1950), Kozlova and Gorbovetz (1966), and Bjprklund area, as no information is available on either radio- and Kellogg (1972), the present author recognized larian stratigraphy or biogeography from pre-Holo- similarities in the faunal assemblages from and cene sediments. The distribution of radiolarians in the the V^ring Plateau. Since these faunal assemblages are surface sediments of the Norwegian- Sea is quite different from the assemblages reported by Ben- discussed in only four papers. Stadum and Ling (1969) son (1972) and Petrushevskaya and Kozlova (1972), reported on the recent distribution of phaeodarians and DSDP Legs 12 and 14 from the northern and equatorial their state of preservation, Petrushevskaya (1969) and Atlantic, respectively, the author concludes that the Petrushevskaya and Bjyfrklund (1974) dealt with the radiolarian population in the North Atlantic and the distribution of radiolarians from surface Norwegian- must have somehow been sediments. isolated. Most likely this was due to a landbridge, the Only one paper, Bj^rklund and Kellogg (1972) deals Iceland-Faeroe Ridge, present during the early phase of with the stratigraphy of Tertiary (late Eocene) the development of the Norwegian-Greenland Sea. Re- sediments, from a site located near the top of one of the cent data from the Aleutian Islands also lead to the diapiric structures on the V^ring Plateau southwest of conclusion, that during early Tertiary, the North the Lofoten Peninsula. R/V Vema of Lamont-Doherty Pacific was isolated from the by a land- Geological Observatory has made several cruises (V 23, bridge, due to an elevation of the Aleutian Islands. V27, V 28, and V 30) into the Norwegian-Greenland The foregoing suggests that the Arctic in the early Sea, taking nearly 200 piston cores. The Tertiary Tertiary was an isolated ocean, which explains why it is sediments were recovered during the two latter cruises. only in the early Tertiary that the Siberian and V^ring Tertiary continental outcrops from northern Plateau faunas have common species. such as Denmark, North Germany, North Poland, and Goll and Bj^rklund (in press) show that the oc- Franz Josephs Land—Novaja Semlja discussed in currence of radiolarians in the surface sediment of the Heiberg, 1863; Hustedt (in O. Wetzel, 1935); Schulz, Norwegian-Greenland Sea is associated with the high 1927; Grundow, 1884, respectively, are all similar in an productive areas in the western Norwegian Sea and absence of radiolarians. However, from other land sec- with the areas in the eastern Norwegian Sea underlying tions on the USSR eastern territories, radiolarian the Norwegian-Atlantic Current (the continuation of assemblages of and Eocene ages have been the Gulf Stream). The Greenland Sea is barren or very described by different Russian authors—Borisenko poor in radiolarians. This distribution pattern is not yet (1960a, b), Krasheninnikov (1960), Kozlova and Gor- fully understood, but the main conclusion must be that bovetz (1966), and Lipman (1950). the North Atlantic Current passing over the Iceland- DSDP Leg 12 went to the area south of the Faeroe Ridge, into the Norwegian Sea, greatly in- Norwegian-Greenland Sea, the Sea, Rockall fluences this distribution pattern, together with dissolu- Basin, and the . Here, Benson (1972) tion and masking effects. reported on radiolarian assemblages with good preser- The main objectives of this study were: to try to es- vation, recovered from sediments of Pliocene to tablish a radiolarian stratigraphy for the Norwegian- Oligocene age, while strongly corroded faunas were - Greenland Sea; to compare the radiolarian fauna tained from Eocene and Paleocene sediments. recovered in the North Atlantic during DSDP Legs 12 Generally no information is available on Tertiary and 14 with that of Leg 38, in an attempt to test the radiolarian stratigraphy in the Norwegian-Greenland hypothesis that the North Atlantic and the Nor- Sea. A well-established Quaternary-Tertiary radio- wegian-Greenland Sea were not connected in the early larian stratigraphy has been established by Riedel and Tertiary; to search for the time when the North Atlantic Sanfilippo (1970, 1971) for DSDP Legs 4 and 7, respec- Current swept over the Iceland-Faeroe Ridge, in other tively, and Moore (1971) for Leg 8 in lower Atlantic words, when did the ridge submerge. Finally, could the and Pacific latitudes. During DSDP Leg 12 to the results of Leg 38 provide information regarding

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PROFILES 65' CONTOUR DEPTHS ARE IN 65° NOMINAL FATHOMS (SOUND VELOCITY 800 fms/fcec.)

DEPTH GREATER THAN IδOOfms. . • EARTHQUAKE EPICENTERS •fc•DRILL SITES EDGE OF j". Base Map from Talwani β Eldholm (in prep) 60' 60° 30° 25° 20° 15° IOe 10° 15° 20° 30° Figure L Location of Leg 38 drilling sites, and bathymetry and structure of the Norwegian - Greenland Sea. (Note: Site 351 was occupied but was not drilled. Its location has not been shown on this map. The inset map shows the track of Glomar Challenger between Sites 338 and 343 on the Voring Plateau. Portions be- tween Sites 339 and 343 correspond to line of composite profile illustrated in accompanying diagram. Also shown are position of Voring Plateau Escarpment, and corrected bathymetry of the area, in hundreds of meters, constructed principally from records taken by R/V Vema of Lamont Doherty Geological Observatory, supplemented by Glomar Challenger data. RADIOLARIA climatic shifts during Pleistocene time, and did the R: Rare—one to five fragments were observed on Pleistocene coolings have any influence on the current half the slide; circulation in the North Atlantic? F: Few—more than five fragments or tests were ob- served on half the slide; MATERIAL AND METHODS C: Common—mostly complete tests. 1-30 tests per All samples used in this study were cleaned using traverse were observed using the 63 X objective; standard procedures. It is of importance to describe in A: Abundant—mostly complete tests, greater than detail how the samples were processed, because an un- 30 tests were observed using the 63 × objective. known "microfossil" was frequently found at Sites 338, These designations are only of limited value due to 344, and 349. In the literature, they are described as the fact that the faunal slides were made in a semi- Anellotubulates. Recently they have been described as quantitative way. For this study, about 700 samples being artifacts, produced by reaction of H2O2 with were processed and examined for radiolarians. pyrite (Pickett and Scheibnerova, 1974, and Richard- son et al., 1973). Perch-Nielsen (1975) reported on and BIOSTRATIGRAPHY illustrated similar "microfossils." The procedures were During Leg 38, Cenozoic sediments were cored from as follows: the Arctic region for the first time, and as similar 1) An equal amount of sediment was used for easier material never has been available, it was now possible observation of fluctuations in the radiolarians per to do a detailed study on Cenozoic radiolarian stratig- volume units of sediment. raphy and paleoecology. Due to time limitations, the 2) Water was brought to the boiling point in a major emphasis of the present contribution is to es- beaker, sample was introduced, then concentrated tablish a northern high-latitude radiolarian biostratig- H2O2 and sodium hexametaphosphate (Calgon) was raphy. It is hoped the biostratigraphic framework out- added. lined in this paper will be useful for the scheduled 3) The suspension was treated with an ultrasound I POD Leg 49. probe for about 10-15 sec, then sieved on a 44 µm The radiolarian assemblages recovered during this screen. leg had very few species in common with holes drilled 4) Residue was treated with HC1, and the ultra- further south in the . As no key fossils, sound probe was used for 5 sec. upon which the lower latitude Atlantic and Pacific 5) The fine fraction of the residue was brought into are based, could be found in sufficient numbers, suspension in the beaker and decanted.. The suspension it was necessary to develop a local Norwegian Sea was allowed to settle out in a clean beaker, and from radiolarian stratigraphy. Again, due to time limita- this fine fraction the fauna slides were made. tions, the taxonomic chapter will only deal with those 6) 0.5 ml was pipetted out and put on a 25 × 50 mm species being significant for this local biostratigraphy. coverslip. Sample was spread out with a toothpick and However, species of little or no value for the dried on a hotplate. stratigraphy, but of value for information on the faunal 7) Caedax (N = 1.56) was put on the slide, a drop or assemblages, are illustrated. two of xylene was put on the coverslip, which was No absolute or good age determination of the sedi- placed on the slide. ment was possible by radiolarians. Therefore, the 8) Slide was allowed to boil for about 30-45 sec to radiolarian stratigraphy obtained had to be correlated dry out the Caedax. to a time scale by correlation with diatoms (Recent- 9) Slide was put on a cold table to get rid of the gas middle Miocene) and silicoflagellates (late Miocene- bubbles faster. Eocene), as reported elsewhere in this volume by The investigations were carried out with a Zeizz Schrader, and Martini and Muller, respectively. Standard RA microscope, normally using the 25 × ob- Species known to be short ranging in equatorial jective and the lO× wide-angle ocular. All micro- sediments are usually lacking in Cenozoic radiolarian photographs were taken with an automatic Leitz assemblages from latitudes higher than about 45°N in Orthomat camera using the lO× objective. the Atlantic Ocean (compare Benson, 1972). This is Comments on abundances and the state of preserva- most likely due to major changes in the ecological con- tion of radiolarians have to be very subjective, especial- ditions at different latitudes. The recent faunal ly the preservation, as this is a mechanism, which is assemblage in the Norwegian-Greenland Sea surface poorly understood and cannot be measured by any in- sediments varies greatly from the assemblage obtained strument. from surface sediments from Rockall Basin. The input Three stages of preservation were used: of radiolarians transported with the North Atlantic P: Poor preservation—when the tests were strongly Current are surprisingly low in the Norwegian Sea sedi- corroded and fragmented; ments underlying this major current system. Also, dur- M: Moderate preservation—when more than 50% of ing Neogene time this transportation effect seems to the tests are fragmented or some corrosion could be ob- have been negligible. Therefore, the majority of the served; radiolarians accumulated in the sediments are believed G: Good preservation—when more than 50% of the to have been endemic to the Norwegian-Greenland Sea. tests were unbroken, and no corrosion could be ob- served. Definition of Radiolarian Zones Five stages of abundances were used: Sediments ranging in age from Recent to early (?) B: Barren—no radiolarians were found on half the Eocene were recovered during Leg 38. To put together slide; a radiolarian stratigraphy was difficult, as no one site

1103 K. R. BJ0RKLUND contained a continuous sediment column, where Cyrtocapsella eldholmi Zone (Samples 338-13, CC radiolarians were present throughout the hole. Thus, to to 12, CC), Early Miocene obtain a stratigraphy ranging from Recent to early (?) Base: Coincident with the top of the Gondwanaria Eocene, data from various sites had to be compiled. japonica Zone. Site 338 turned out to be most important for the es- Top: Extinction of Gondwanaria japonica and the tablishment of the radiolarian stratigraphy, as this site first occurrence of Cyrtocapsella eldholmi, Hexalonche contained radiolarian-bearing sediments ranging from late Miocene to late (?) Eocene. From this site, 10 sp. B, Stichocorys biconica, and Heteracantha dentata. radiolarian zones were recognized. Stichocorys biconica Zone (Samples 338-12, CC to 11-2, 115-117 cm), Early Miocene Calocyclas talwanii Zone (Samples 338-29, CC to 27-3, 76-78 cm), Late Eocene Base: Coincident with the top of the Cyrtocapsella eldholmi Zone. Base: Not defined, radiolarians absent below 29, Top: Extinction of Velicucullus oddgurneri. CC. Top: First appearance of Lophocorys norvegiensis Actinomma holtedahli Zone (Samples 338-11-2,115-117 cm and the extinction of Calocyclas talwanii and Phaco- to 10-2, 146-148 cm), Early-middle Miocene discus testatus. Base: Coincident with the top of the Stichocorys General: Lithomitra sp. B and Botryostrobus sp. P biconica Zone, and the first occurrence of Ceratocyrtis (Petrushevskaya and Kozlova, 1972) are present histricosus and Hexalonche sp. A. throughout the zone. Top: Extinction of Stichocorys biconica, Hexalonche Lophocorys norvegiensis Zone (Samples 338-27-3,76-78 cm sp. B, Actinomma holtedahli, and Cyrtocapsella to 25, CC), Late Eocene eldholmi. Base: Coincident with the top of Calocyclas talwanii Lithomelissa stigi Zone (Samples 338-10-2,146-148 cm to 8-2, Zone. 53-55 cm), Middle Miocene Top: Not well defined, as radiolarians are strongly Base: Coincident with the top of the Actinomma corroded above 26-3, 76-78 cm. holtedahli Zone. General: Lithomitra sp. B and Botryostrobus sp. P Top: Not well defined, as the sediments above 8-2, (Petrushevskaya and Kozlova, 1972) are present 53-55 cm have a low radiolarian species diversity and throughout the zone. are barren above 7, CC. A radiolarian assemblage from Site 337 of an early Phorticium sp. A Zone (Samples 338-24-3,62-64 cm (?) Oligocene age was recovered. Lithomitra sp. A was to 21, CC), Oligocene frequently found, and as this species was found in the Base: Not well defined, as sediments below 24-3, 62- upper late Eocene, but not in the Oligocene sediments 64 cm are strongly corroded. at Site 338, the Site 337 radiolarian assemblage is be- Top: Coincident with the first occurrence of Cerato- lieved to be stratigraphically between the two assem- cyrtis robustus, Actinomma (?) sp. A, and a very char- blages as reported from Site 338. One radiolarian zone acteristic, not identified Nassellaria (only fragments of was suggested based on the faunal assemblage recov- cephalis and thorax), Nassellaria sp. A. ered. General: Ceratocyrtis mashae present for the first time in 23-3, 72-74 cm. Lithomitra sp. A Zone (Samples 337-9-3, 20-22 cm to 11, CC) Early (?) Oligocene. Ceratocyrtis robustus Zone (Samples 338-21, CC to 19-3, 80-82 cm), Oligocene Base: Not defined. Base: Coincident with top of the Phorticium sp. A Top: Not defined. Zone, and the first occurrence of Ceratocyrtis robustus. A radiolarian assemblage from Site 339 of a middle Top: Extinction of Nassellaria sp. A and Spongo- (?) Eocene age was recovered. As this site was near the melissa sp. Chen, 1975. top of a diapir, it is questionable how valuable this site will be for stratigraphic purposes. However, one radio- larian zone was suggested based on the faunal assem- Velicucullus oddgurneri Zone (Samples 338-19-3,80-82 cm blage recovered. to 18, CC), Oligocene Base: Coincident with the top of the Ceratocyrtis Artostrobus (?) quadriporus Zone (Samples 339-12, CC robustus Zone. to 9, CC), Middle Eocene Top: Extinction of Phorticium sp. A and the first oc- Base: Not defined. currence of Gondwanaria japonica and Eucyrtidium sp. Top: Not defined. The oldest radiolarian assemblage recovered during Gondwanaria japonica Zone (Samples 338-18, CC this leg was obtained from Site 343. Here, a radiolarian to 13, CC), Early Miocene composition quite different from that at Site 339 was Base: Coincident with the top of the Velicucullus recovered. Compared with the faunal assemblages de- oddgurneri Zone. scribed in Kozlova and Gorbovetz (1966) from Top: Extinction of Ceratocyrtis robustus. Komissarovo, Well 4-K, and from Ingalinsk, Well 1-K,

1104 RADIOLARIA

Archnocalpis (?) tumulosa was frequently found in 5, during Leg 28 (Chen, personal communication). As the CC, but was also present in 6, CC. An early Eocene age range of Antarctissa whitei is not definitely stated, the was based on the recovered silicoflagellate assemblage, base of the Cycladophora davisiana Zone may not have and a radiolarian zone is suggested even if the base and been correctly placed. However, at this stage, the base top are not defined. is suggested to be near or closely equal to the Pliocene- Pleistocene boundary. Archnocalpis (?) tumulosa Zone (Samples 343-6, CC In summary, a list of the Norwegian Sea radiolarian to 5, CC), Early Eocene zones is given in Table 1. The zones are listed from Base: Not defined. younger towards older. Top: Not defined. Late Miocene, Pliocene, and Pleistocene sediments TABLE 1 were recovered from Sites 341 and 348, and it was dif- Norwegian Sea Radiolarian Zones ficult to put this upper zonation together. In Sample 338-7, CC, there was a high concentration of Hex- Cycladophora davisiana Zone alonche sp. A. This species was hardly observed in Sam- Antarctissa whitei Zone Unzoned ple 338-8-2, 53-55 cm, the latter believed to be close to Lithomelissa stigi Zone the middle-late Miocene boundary. The high occur- Actinomma holtedahli Zone rence of Hexalonche sp. A is, therefore, believed to be Stichocorys biconica Zone close to the base of the late Miocene. This species was Cyrtocapsella eldholmi Zone also found in high numbers at Site 341 (Sample 15-2, Gondwanaria faponica Zone Velicucullus oddgurneri Zone 30-32 cm), and Site 348 (Sample 31-5, 17-19 cm). In Ceratocyrtis robustus Zone those sites Hexalonche sp. A had a very short time Phorticium sp. A range of mass abundancy, and most likely this species Lithomitra sp. A had a "bloom" all over the Norwegian Sea in early late Lophocorys norvegiensis Zone Calocyclas talwanii Zone Miocene, and may, therefore, serve as a good time Artostrobus (?) quadriporus Zone marker. Above this Hexalonche sp. A peak at Site 348, Acronocalpis (?) tumidula Zone a complete sediment column was suggested based on the diatom and silicoflagellate zonations. For Site 348, a radiolarian zonation from late Miocene to Recent SITE DESCRIPTIONS could be defined. In the following section, all sites drilled during Leg Antarctissa whitei Zone, Late Miocene-Pliocene 38 will be discussed. Sixteen sites were drilled, but only a few were of stratigraphic importance for establishing Base: Coincident with the first occurrence of Ant- a radiolarian zonation for the area. Therefore, range arctissa whitei. tables will be presented for only the selected sites, and Top: Extinction (?) of Antarctissa whitei. generally only radiolarians of stratigraphic significance Remarks: The Antarctissa whitei Zone overlies an are included. Tables listing samples studied, but barren unzoned interval at both Sites 341 and 348. This zone of radiolarians are given for each site. may be extended both upwards and downwards, as sediments above and below are characterized by having Iceland-Faeroe Ridge a low radiolarian diversity of a moderate to poor Ruddiman and Mclntyre (1973) showed that the preservation. However, Antarctissa whitei has a very polar front during the maximum of the last glaciation robust test, and have most likely survived dissolution. was situated almost east-west, along 45°N latitude. At this stage, the Antarctissa whitei Zone ranges from This implies that the surface water circulation in the upper late Miocene to the Pliocene-Pleistocene bound- northern Atlantic during glacial periods was different ary. The last occurrence of Antarctissa whitei at Site from the present circulation system. During the last 348 is in Sample 5-5, 147-149 cm, and the Pliocene- glacial period, the North Atlantic Current did not flow Pleistocene boundary based on diatoms has been into the Norwegian Sea over the Iceland-Faeroe Ridge, placed within Core 5. (See Schrader, this volume.) but traveled eastward south of 45°N latitude, and turn- ed southward along the Spanish-West African coast. Cycladophora davisiana Zone, Quaternary From piston core studies in the Rockall Basin carried Base: Coincident with the top of the Antarctissa out by the author, it was observed that the occurrence whitei Zone. of radiolarians fluctuated, being abundant in inter- Top: Recent sediments. glacial, carbonate-rich sediments, and barren in glacial, Remarks: Generally the "Glacial" sediments recov- carbonate-poor sediments. Piston core studies from the ered during this leg are barren of radiolarians. Only Norwegian Sea show that the Recent sediments are from Sites 336, 341, 348, and 349 were a considerable relatively rich in radiolarians, but the species diversity amount of radiolarians obtained. Cycladophora is low compared to lower latitudes. It was also ob- davisiana was present in all "Glacial" samples con- served that, throughout the Norwegian Sea, the radio- taining radiolarians at Site 336, but was only scattered larians disappear from the sediments close to the 18 K throughout the Pliocene-Pleistocene sediments at Site level, and have, so far, not been obtained from deeper 348. C. davisiana seems to occur for the first time in the sediments. The questions which arise are: why are North Atlantic near the base of the Pliocene. This is in radiolarians absent in earlier interglacials in the agreement with the studies carried out in the Antarctic Norwegian Sea sediments? Is it because of dissolution,

1105 K. R. BJ0RKLUND

masking effect by terrigenous sediments, or lack of pro- TABLE 2 duction? These complex questions are still not solved, Pliocene-Pleistocene but one of the sites on the Iceland-Faeroe Ridge Samples Studied for brought new information on the occurrence of radio- Radiolarians - Site 336 larians in the "glacial" sediments. Interval Core Section (cm) Site 336 In the Pliocene-Pleistocene sediments recovered, 1 1 49-51 1 1 131-133 radiolarians are present in the interglacial periods, nor- 1 2 35-37a mally of a good preservation in the upper half of the 1 2 4547a sediments, and moderate to poor in the lower part. 1 2 124-126a 1 3 4042a Radiolarians are absent in the glacial period sedi- a ments. 1 4 40-42 1 5 61-63 It has been noted that radiolarians from the 1 5 131-133 Norwegian Sea had been found only in the Holocene 1 CC sediments, and it was still questionable whether 2 1 92-94a radiolarians were present in earlier interglacial periods. 2 2 20-22a Site 336 showed that at the northern flank of the 2 2 88-90 2 3 3-5 Iceland-Faeroe Ridge a repetition of radiolarian-rich 2 3 84-86 intervals occurred (compare Table 2). These intervals 2 4 64-66 with high radiolarian content and low input of ice- 2 4 119-121 rafted material are believed to reflect better ecological 2 CC conditions during interglacial periods. The species 3 1 76-78 3 1 138-140a diversity is much lower than in sediments of the same 3 2 61-63a age from the Rockall Basin, indicating that the North 3 CC Atlantic Current transported very limited amounts of 4 1 133-135 radiolarians from the North Atlantic into the Nor- 4 2 84-86a wegian Sea. However, it is of interest to observe the 4 CCa high percentage of Cycladophora davisiana (65% and 5 1 77-79 5 2 63-65 58% in Samples 1-4, 40-42 cm and 2-1, 92-94 cm, 5 3 53-55 respectively), while Cycladophora davisiana only makes 5 4 20-22 up 2%-3% in the surface sediments. 5 4 125-127 a Late (?) Oligocene radiolarian-bearing sediments 5 5 70-72 5 5 125-127a were recovered from 15-1, 33-35 cm to 19, CC (Figure 5 6 55-57 2, Table 3). The biogenous silica in this part is generally 5 6 13O-132a made up of broken sponge spicules. The radiolarian 5 CCa species diversity is relatively high, with a majority of 6 0 27-29 unidentified Lithomitra spp., Stylodictya spp., and 6 1 40-42a 6 2 25-27a members of the family Spongodiscidae. Velicucullus a 6 2 145-147 oddgurneri and Ceratocyrtis mashae were present in 6 3 33-35 Samples 15, CC through 17, CC (see Table 3). Siliceous 6 3 135-137 microfossils are lacking in the sediment column from 6 4 35-37 6 4 145-147a Samples 20-3, 70-72 cm to 40, CC. a Table 4 lists the Glacial-Recent radiolarian species. 6 5 25-27 6 5 145-147 No attempt was made to observe the stratigraphic 6 6 35-37 range for all the Recent species. Only those sites having 6 6 135-137 a reasonable amount of species are included in Table 4. 6 CC 7 CC Site 352 8 1 25-27a 8 1 33-35 This site was drilled on the southern flank of the 8 2 35-37a Iceland-Faeroe Ridge. Radiolarians from the Pleisto- 8 2 125-137 cene section (Samples 1-3, 30-32 cm to 3, CC, Table 5, 8 3 20-22 Figure 3) were recovered, having a rare abundance, and 8 3 115-117 8 4 25-27a generally a moderate to poor preservation. a 8 4 115-117 Radiolarians were also present in middle(?)-late 8 5 50-5 2a Oligocene sediments (Samples 352A-1, CC to 3, CC, 8 5 130-132a Table 5, Figure 3). 8 6 20-22a In Hole 352A, radiolarians were not recognized, as 8 6 90-92 8 CCa the material was very fragmented and strongly corrod- a 9 1 125-127 ed. Also at this site, as at 336, the majority of bio- 9 2 30-32 genous silica consisted of broken sponge spicules. One 9 2 75-77a of the main objectives from a paleontological point of 9 3 4042a view was to compare the faunas on both sides of the

1106 RADIOLARIA

TABLE 2 - Continued Site 336 Interval c o (O • - Core Section (cm) •r- +J σ> S- 3 o>, 9 a > 'o •i- IΛ O C 3 75-77 Depth αj o cu ^fe ^5 to Radiolarian 9 4 10-12 (m) o cu •?'£>, ? zonation 9 4 120-122a 9 5 33-35 s A/G 9 5 135-137 mmmm•g - -1.8 9 CC >, a -σ 10 1 75-77 c CD E r^ O Radiolarians observed. - 250 '£ -o" O LJ-1 c

1107 K. R. BJ0RKLUND

TABLE 3 TABLE 4 Pre-Glacial Samples Radiolarians Separated from Studied for Upper "Glacial" Sediments Radiolarians - Site 336

Interval Sites

Core SectiorI (cm) >sD oo ro ro ro ro ro «t ro 15 1 33-35a ro a 15 CC Arachnosphaera dichotoma X X 15 3 13-15a a Cladococcus viminalis X X X 16 CC Cromyechinus borealis X X X X X 17 CCa X X 18 3 30-32a Drymyomma elegans 18 cca Echinomma leptodermum X X X X X 19 1 130-132a Echinomma sp. X X X X X 19 CCa Hexaconthium enthacanthum X X X X 20 3 70-72 Hexaconthium pachydermum X X 20 cc Larcospira minor X X X X Cores 21-40 core catchers. Lithelius spiralis X X Phorticium clevei X X X X X Radiolarians observed. Rhizoplegma boreale X X X X X Spongodiscus osculosus X X X Spongodiscus resurgens X X X X X V^ring Plateau Spongotrochus glacialis X X X X The V^ring Plateau is a relatively flat (about 1200 m) Streblacantha circumtexta X X X X X submarine plateau. The plateau is a prominent feature Stylodictya tenuispina X X of the continental slope off Norway (Figure 1), and its Stylodictya validispina X origin and age have been a subject of considerable speculation. Talwani and Eldholm (1972) described the Nassellaria V^ring Plateau Escarpment, which is a buried escarp- ment with a roughly northeast-southwest trend. This Amphimelissa setosa X X X X X Androcyclas gamphonycha X X escarpment divides the V^ring Plateau in an outer and Artostrobus annulatus X X X X X an inner part. A considerable thickness of sediments, Artostrobus joergenseni X X X X perhaps up to 8 km, may extend into the Mesozoic or Botryostrobus plathycephalus X X X even Paleozoic. Botryostrobus tumidulus X Campylacantha cladophora X Outer V0ring Plateau Ceratocyrtis glaeus X X X Ceratocyrtis histricosus X X X Site 338 Ceratospyris hyperboreus X This site is located on the inner part of the Cladoscenium tricolpium X X topographic "high," and was the only site having Corocalyptra craspedota X X radiolarian-bearing sediments ranging through most of Cornutella profunda X X X the late Eocene to late Miocene (Figure 5, Table 7). Cycladophora davisiana X X X X X Dictyoceras acanthicum X Miocene and Eocene radiolarians are characterized by Euscenium (?) corynephorum X X good preservation and a high species diversity, while in Gonosphaera primordialis X X the Oligocene sediments, the species diversity is low, Litharachnium tentorium X X preservation moderate to poor, with an increase in the Lithostrobus cuspidatus X X Trissocyclidae. Lithomelissa hystrix X X The "Glacial" sediments are generally barren in Lithomelissa setosa X X X X X radiolarians, only in Sample 1-1, 0-2 cm was a rich Lithomitra arachnea X faunal assemblage recovered, the preservation being Lithomitra lineata X X X X good. All the rest of the Pliocene-Pleistocene sedi- Peridium longispinum X X X ments are barren of radiolarians (Table 8). Hexalonche Phormacantha hystrix X X X X X X sp. A are abundant in Sample 7, CC, being absent Plagiacantha arachnoides Plectacantha trichoides X above and rare below this sample. This peak of Hex- Pseudodictyophimus gracilipes X X X X alonche sp. A, based on silicoflagellates, occurs in the Stichocorys seriatus X X late Miocene, but close to the middle-late Miocene Theocyrtis borealis X X X boundary. Very few species being key fossils for the lower latitude radiolarian stratigraphy were observed. Stichocorys diploconus, Cyrtocapsella tetrapera, and characterized by a relatively low species diversity and Cannartus violina were found only at a few horizons. rare to poor preservation in the lower part. Phorticium One specimen of C. violina was observed in Sample 10, sp. A is characteristic for the Oligocene sediments. CC, while C. tetrapera was found in Sample 17, CC, as- Eocene radiolarian-bearing sediments (Samples 26-3, sumed to be in the lower part of the early Miocene. 62-64 cm, through 29, CC) do have a high species diver- The Oligocene sediments (Samples 18-1, 110-112 cm sity and good preservation. Lophocorys norvegiensis, through 24-3, 62-64 cm, Figure 5, Table 8) are Calocyclas talwanii, Peripyramus magnifica, Lithomitra

1108 RADIOLARIA

TABLE 5 TABLE 6 Pliocene-Pleistocene Samples Studied for Samples Studied for Radiolarians — Site 337 Radiolarians - Site 352 Interval Core Section Interval Core Section (cm)

Hole 352 1 3 30-32a 1 CCa 1 CC 2 3 100-102a cc 2 a 4 CC cc a 5 3 3 110-112 cc 3 CCa Hole 35 2A 4 3 4042 4 CC 1 cc 5 3 80-82 2 cc 5 CC 3 cc 6 2 65-67 6 CC 7 3 83-85 7 CC 8 2 20-22 SITE 352 & 352A 8 CC 9 3 20-22a c c o 9 cca •I- 4-> a S. 3 10 3 20-22 S- a αj O i. 10 cc a Depth £ S Radiolarian 11 3 25-27 a (m) S £ Litholog y Ag e αS zonation 11 cc R/M 12 3 20-22

a ,ia l 12 CC i— 3 davisiana •c CD E R/P aRadiolarians observed. - 50 Site 342 This site is located on the outer part of the topographic "high," and only early Miocene sedi- R/P — 100 Nann o ooz e ments had considerable amounts of radiolarians of a R/P liddl e Oligoce n Unzoned good preservation (Figure 6, Table 10). Cyrtocapsella R/P tetrapera (Plate 17, Figures 19, 20) occurred in rela- tively high numbers in Sample 3, CC, correlated to Site Figure 3. S#e summary - Site 352, Holes 352 and 352A. 338 with an upper early Miocene age. C. tetrapera are not common in the Norwegian Sea sediments, but were reported by Benson (1972) as abun- dant in upper early Miocene at Site 116, Leg 12. It is SITE 337 worth mentioning that the occurrence of C. tetrapera in c c o the Norwegian Sea most likely is a result of trans- fC •r- >> •r- +> >, CT> S_ 3 portation by the North Atlantic Current, and is, there- S- O rri n O O i- fore, taken as evidence for a definite submergence of Depth t 8 5 αj ÷S to Radiolarian the Iceland-Faeroe Ridge during the upper late Mio- Im) _J cc OL -σ zonation cene. R/M CyaladoTphova '^•σ R/G Velicucullus oddgurneri was observed in Sample 6,

Plei . davistana 5 E F/P CC. Basement (?) was recovered directly under these I early Miocene sediments, while early Eocene sedi- - 50 Pli o ments were recovered at Site 338. Both sites are on the

Barre n same topographic "high," and the difference in age between the two sites may be due to either: (1) that F/M Lithomitva basement is a sill, or (2) that Site 342 had a more C/G sp. A Terrigenou s — 100 mud , sand y mu d effective submarine erosion than Site 338. Two zones, defined at Site 338, were recognized at Site 342 (Figure E- M Oligo . 6).

i Barre n Basal t Site 343 Figure 4. SzYe summary - Site 337. This site is located at the eastern margin of the Lofoten Basin, at the foot of the V0ring Plateau, and sp. A, and Botryostrobus joides are characteristic this site yielded the oldest sediments, early Eocene. The species. Older Eocene sediments are barren of siliceous sediment is generally terrigenous, and biogenic silica microfossils (Table 9). Ten radiolarian zones were sug- was observed, having a good preservation, only in gested for this site (Figure 5). Samples 5-3, 55-57 cm through 6, CC. However, some 1109 K. R. BJ0RKLUND

TABLE 7 SITE 338 Pliocene-Pleistocene Samples Studied for Radiolarians - Site 338 Core Section Interval (cm)

a Depth Radiolarian 1 1 0-2 On) zonation 1 1 84-86 1 1 127-129 1 1 136-138 1 1 143-145 1 2 80-82 1 2 110-112 - 50 1 2 130-132 1 2 141-143 C/G Lithomelisβa 1 3 23-25 stigi 1 3 69-71 1 3 118-120 -100 A/G Aatinomma holtedahli 1 4 45-47 Stiahoaorys hioonioa 1 4 93-95 Cyvtocapcella eldholmi 1 4 126-128 1 CC 2 1 77-79 - 150 C/G Gondwanaria japonica 2 1 121-123 2 2 70-72 2 2 127-129 Veliouauilus oddgurneri 2 3 43-45 -200 Ceratocyrtis robustus 2 3 133-135 C/G 2 4 10-12 2 4 77-79 R/M • Phovticium sp. A 2 CC 3 2 52-54 I R/P Unzoned - 250 3 2 122-124 Lophoaorys novvegieneis 3 3 132-134 A/G Caloeyolas taZwanii 3 3 136-138 C/G 3 4 17-19 3 4 35-37 — 300 3 4 102-104 3 4 130-132 3 CC 4 1 116-118 4 2 35-37 - 350 4 2 116-118 4 3 96-98 4 4 29-31 4 4 108-110 4 CC -400 5 2 53-55 5 3 76-78 5 3 135-137 5 4 81-83 5 5 10-12 5 5 78-80 5 6 30-32 5 6 120-122 Figure 5. Site summary - Site 338. 5 CC

a strongly corroded fragments were found in Samples 12, Radiolarians observed. CC and 13, CC (Figure 7, Table 11). Sediments younger than early Eocene, but older than the "Glacial" are ab- transported from the Atlantic by the North Atlantic sent, most likely due to submarine erosion. Current. Substantial submarine erosion is believed to have taken place at Sites 342 and 343. Conclusion, Outer V^ring Plateau The best site for biostratigraphic purposes turned out Inner V^ring Plateau to be Site 338. Radiolarian-bearing sediments were This part of the plateau is located on the landward present from late Eocene to lower late Miocene. The side of the V^ring Plateau Escarpment. Basement was Norwegian Sea radiolarian stratigraphy is basically not noted on seismic profiles, and the sediment compiled from Site 338, with additional information thickness is assumed to be as much as 8 km. It was in from a few other sites. these sediments that the prime biostratigraphic site was Cyrtocapsella tetrapera in the Norwegian Sea to be drilled. sediments is taken as evidence for a definite sub- Closer to land, the plateau has a very "mountainous" mergence of the Iceland-Faeroe Ridge during late early appearance due to a number of diapiric structures. Miocene, as C. tetrapera is understood as being These were drilled in an attempt to find sediments older mo RADIOLARIA

TABLE 8 Radiolarian Species Distribution, Abundance and Preservation - Site 338

.o. S3 te ._ -S3 ^ Mi? ! lit if!\t\la tllii!**!!*!* }\\h -* iijifi Hiijiuπif iiuiffi1111i11 tit • (Interval | g S ! ^ I I H ^ «l " " •S 2 ^ ^ ill^^l^H^III••&lMl 7,CC C/G A F 8-2,53-55 C/G FFFARCRR 8-2, 120-122 C/G F F F A R F R 8-3,45-47 C/G FFFARFRR 8-3, 135-137 C/G R F A R F R . 84,55-57 C/G " R F A R F 8-4, 145-147 C/G F A F R 8,CC C/G R F A F R R 9-1,85-87 R/G R C F R 9-1,145-147 R/G R R C 9,CC C/G ~ C C R F 10-1,115-117 C/G RRFCRCRFR 10-2,60-62 C/G R FRF RA RRA 10-2, 146-148 A/G F R F R R C F R F R R 10, CC A/CT C R A R F R 1- R F , 11-1,145-147 C/G " R F C R R R F C R F F F R R 11-2,115-117 R/G R R R C R F F F 11-3,135-137 C/G CF RRR RRACRCFR RR 11, CC A/G RRR R R F A C R F R R R 12-2, 145-147 C/G R^ji RRRR CRl•RCR 12, CC A/G R RRRCRFCRR 13-1, 145-147 C/G C R F C R R R 13-3, 145-147 R/G C R R C F F R 13-5, 125-127 A/G R F R R R F F R R 13, CC C/G RRR R F F F F 14-2, 140-142 C/G R R R R C F F R R 14, CC C/G R R R R C F F R 15-2, 145-147 R/G R RRRCCRRR 154,130-132 R/G R RRRCCRFR 15, CC C/G R RRR FCRC R 16-2,60-62 C/G R R R R C F R F R 16-5,20-22 C/G R R R C F R R 16, CC C/G R RRRFRRR 17-2, 140-142 C/G R R R F F R R R 17, CC R/G R R RRRR F 18-1,110-112 R/G " RRRRFRFRR 18, CC R/G R RRRRRRR 19-3,80-82 R/M R R R R R R 19, CC C/G R F R C 20-5,60-62 R/P R RJ? 20, CC C/M F R R F R 21-1, 100-102 C/G C R R R F C F R 21.CC C/G C R R R R C F R 224,79-81 R/M R RRR 22, CC C/G F^ C^ F R R 23-3,72-74 C/M F R F R R 23, CC R/M F R 24-3,62-64 R/M R 24, CC B 25-1,134-136 B 25, CC B 26-3,67-69 A/G R R R A F R 26 CC C/G R R F R R 27-3,76-78 C/G RRRRRRRR 27, CC A/G RRRRRRRR 28-2,54-56 C/G R R F R R R R 28, CC C/G R R R R R 29-1,148-150 C/G R R R R R R 29, CC C/G RRRR

1111 K. R. BJ0RKLUND

TABLE 9 Pre-Glacial Age Samples SITE 343 Barren of Radiolarians-Site 330

rcσ or- >l •r- +J Core Section Interval (cm) cn S- =J O rσ _Q CD r— i— 'r— > o o s- 30 2 42-44 Depth £ S , ,J2 T3 , T3 Cn O S_ 3 o 'o E N CD Depth s- u αi ^ "S Radiolarian O O CD CD cn - 150 13 (m) <_> i~ 'Z < ai -5 zonation O c/1 o R/M CD O cn , Q- O T3 CD C -200 r— rσ - 50 rσ c/1 rσ •r- CO s- c rσ >, sE r— O 3 >, C/G .a rö

Figure 6. £#

1112 RADIOLARIA

TABLE 11 TABLE 12 Samples Studied for Pliocene-Pleistocene Radiolarians - Site 343 Samples Studied for Radiolarians - Site 339 Interval Core Section (cm) Interval Core Section (cm) 1 2 4749 1 CC 1 3 6 3-65 a a 2 3 66-68 1 CC 2 CC 2 3 70-72 3 3 80-82 2 CC 3 CC 3 3 90-92 4 2 53-55 3 CC 4 CC 4 3 83-85 5 3 55-57a 4 CC 5 CCa 5 2 94-96 6 1 145-147a 6 4 84-86 6 CCa 6 CC 7 3 35-37 7 3 79-81 7 CC 7 CC 8 2 60-62 8 1 23-25 8 CC 8 1 130-132a 9 2 4547 8 2 110-112a 9 CC 8 3 80-82a 10 2 55-57 8 4 98-100a 10 CC 8 CC 11 2 60-62 9 CCa 11 CC 10 2 140-142a 12 2 80-82 10 CCa 12 cca 11 1 117-119a 13 cca 11 CCa 14 cc 12 2 110-112a 15 2 80-82 15 CC aRadiolarians observed.

Occurrence of early Eocene radiolarians. SITE 340 c £= O >, •r- -£ SITE 339 >, cn s_ =3 S- O «X1 c o >> ••- +J Depth £8 5 , σ>• t. a 1 S- O o J3 (m)

C/G

- 50 A/G Lophooorys Barre n Siliceou s ooz e Pliocene - Pleistocen e i norvegiensis Glacia l mud , sand y mu d — 100 C/G Lat e Eocen A/G Artostrobus quadripo~fus -100 C/G Figure 9. Site summary - Site 340. Eocen e M & L Siliceou s ooz e

Figure 8. Site summary - Site 339. Miocene age for these redeposited sediments (Figure 10). The Pliocene-Pleistocene sequence directly overlying margin. The hole drilled through a Pliocene-Pleisto- late Miocene sediments has a high radiolarian species cene section, nearly five times as thick as at Site 338. diversity, and all siliceous microfossils are of a good Radiolarians are not generally present in this section. preservation (Figure 10, Table 15). Antarctissa whitei, Only in Samples 4-2, 94-96 cm to 7, CC was a re- Ceratocyrtis mashae, C. compacta, Heteracantha den- worked radiolarian assemblage of good preservation tata, Triceraspyris sp., Hexalonche sp. A, Gondwanaria obtained (Figure 10, Table 14). Velicucullus odd- japonica, and Velicucullus oddgurneri were frequently gurneri, Stichocorys biconica, Eucyrtidium sp., and observed. Hexalonche sp. A are abundant in Sample 31- Hexalonche sp. A do indicate an upper middle to late 5, 17-19 cm, assumed to correspond to Sample 338-7,

1113 K. R. BJ0RKLUND

TABLE 13 Late Eocene Samples SITE 34 Studied for c o Radiolarians - Site 340 ro •i- •i- +-> σ> S- 3 o ro -Q Interval CD > >o> O i- CD O JZ Core Section (cm) Depth CD T3 w Radiolarian Os- CuD (m) c_> !- ü < c? T3 zonation 1 3 85-87 1 CC • αi s- c C> T3 c 8 3 45-47 - 150 (T3 8 CC l/> α> 9 3 35-37 T3 9 CC o +-> 10 3 45-47 —O 'r- c 10 CC oππ c CD α> CΛJKJ α> S- 11 3 σi Q- 45-47 s_ α> fθ CO 11 3 CC α) α> j— u o

All samples contain radio- D- larians, but sh ow a reversed - 250 (?) stratigraphy.

CC. Two radiolarian zones were suggested from this site. -300 Conclusion, Inner V0ring Plateau • Sediments from both Sites 339 and 340 are com- - 350 posed of Tertiary biogenous siliceous oozes, which are α> C/M α> believed to be the principal material of the diapir cores. u o A principal question is what is causing the relatively CD '^L G/M wnte% o O- thick layer of displaced Tertiary material in the o α> Pliocene-Pleistocene section. Since this site is only a —400 c A/G o α> α> short distance northwest of the diapiric area, and the u α> o A/G Unzoned diapir cores are Tertiary biogenous siliceous oozes, it is - fθ •r- CD A/G assumed that this body of displaced Tertiary material CD £= Lithomelissa Ti—3 αU> represents the time of principal diapirism. As the T3 O - 450 C/G stigi Pliocene-Pleistocene sediments are without radio- I £ £ larians they cannot indicate the time for the onset of the diapirism. Figure 10. Site summary - Site 341.

Knipovich Ridge Mohns Ridge Site 344 It was assumed that this site would be of great value Site 345 from a paleontological point of view, as it was the This site was located in the western part of the northernmost site drilled. However, as the sediments Lofoten Basin, near the eastern flank of the Mohns were barren of any kind of siliceous microfossils, and Ridge. Pliocene-Pleistocene sediments were character- the fact that "Glacial" sediments were not penetrated, ized by being barren in radiolarians (Figure 12, Table information on whether the preglacial siliceous oozes 16). Early Miocene radiolarian assemblages were recov- were present that far north was not obtained. It will be ered in Samples 6-1, 43-45 cm to 10-5, 30-32 cm (Figure of great interest to learn whether the Paleogene 12, Table 17). Other preglacial sediments were also siliceous oozes, occurring further south in the barren of radiolarians (Figure 12, Table 18). No zona- Norwegian Sea, did extend into the Arctic Ocean. Only tion was done for this site, but the occurrence of Heter- core-catcher samples were prepared and studied for acantha dentata in Sample 6-1, 43-45 cm may indicate radiolarians (Figure 11). that this sample belongs to the Stichocorys biconica

1114 RADIOLARIA

TABLE 14 (Figure 13, Table 19). This section is unzoned, but Samples Studied, Either Barren or again, as at Site 345, Heteracantha dentata are present, Having Displaced Radiolarian Assemblages — Site 341 indicating a maximum age for Sample 4-2, 95-97 cm of upper early Miocene. However, the age is probably Core Section Interval (cm) younger. The rare radiolarians and their bad stage of preservation do not allow a more exact date. In addi- 1 3 88-90 tion, Velicucullus oddgumeri and Ceratocyrtis mashae 1 CC 2 2 64-66 were observed. 2 CC Site 347 3 3 88-90 3 CC This site is located a short distance southwest of Site 4 2 94-96 346. Only core catchers were studied for radiolarians. 4 CCa a An abundant, modern radiolarian assemblage of good 5 3 88-90 5 CCa preservation was recovered from Sample 1, CC. The 6 2 92-94a rest of the samples were barren of radiolarians (Figure 6 CCa 14). 7 3 92-94a 7 CCa Site 349 8 3 83-85 8 CC This site is located on the Jan-Mayen Ridge, 9 3 86-88 southeast of Sites 346 and 347. Nearly all core-catchers 9 CC samples were barren of any kind of siliceous 10 3 120-122 10 CC TABLE 15 11 3 100-102 Radiolarian Species, Abundances, Preservation - Site 341 11 CC 12 3 95-97 12 CC Cores 13-15, Core-catcher samples

16 1 105-107 E? to SU .- 16 CC K £S 0 17 2 0 70-72 •~ 17 CC 1 'v •s < f T3 0 à .§, "•s ė 18 1 30-32 S (3 σ3 "1 fit X 18 CC δ • 8.2 S is. -2 19 1 145-147 o 53 SJ - 19 CC Sample •o > 0 p O 2 '- : fi

1115 K. R. BJ0RKLUND

''; SITE 34'I SITE 345 CD -P π (O CO'— c o 1— •i- +-> Cn c>n> Z3 >> o>> >> o +J αj i— •- O α> 1— •I— o o O U- •— o o s- r— cu o CD >O Depth s. u +J rö •r- £= o α> cn to i- (m) C_> S- zonation (m) H <

03 i -p i +-> α> (J O •l- O •i- s_ •r- CD •r- CD Q- Q- CS E Q_ Q. O3

- 50 - 50 CD α> — c A/G o α> CD O 1 cn o C/G fα =J Unzoned I o o F/M CD CJ s- C/G — 100 -100 ••• Lü CJ> LO 1 F/M •ar α> T3 α> α> c u ε CD O - 150 o cn >> - 150 o •<- T3 C Σ O

T3 rt3 • cu T3 — 200 CJ -200 ε o r i ,— ' ~ OS Q_ ——- EQ

T3 E 1 - 250 - 250 • —— >> T3

T3

E — 300 — 300 t CD -5 CD 1 C o α> αi CD £= U CD U CD O cn o O •!- cn O i— • S- "r" CD o >> I - 350 CD i— - 350 +-> S- _J CD |

— 400 — 400 = CO

Figure 11. Site summary - Site 344. - 450 microfossils. However, Samples 1-1, 10-12 cm and 1, CC had a good, well preserved, modern radiolarian fauna. One specimen of Amphimelissa sp. was recog- Figure 12. Site summary - Site 345. nized in Sample 13, CC. This was also found at Site 338, indicating a late Eocene age (Figure 15). Iceland Plateau Site 350 This site is the southernmost site on the Jan-Mayen Site 348 Ridge. All core-catcher samples, except for 1, CC and This site is located west of the Jan-Mayen Ridge and 3, CC, where few radiolarians of a bad preservation is characterized by having a relatively rich, and well to were observed, are barren of any kind of siliceous moderately preserved radiolarian fauna from Recent to microfossils (Figure 16). One specimen of Heter- middle Miocene (Figure 17, Tables 20 and 21). The acantha dentata was present in Sample 3, CC, and using abundance and preservation of radiolarians vary great- its range from Site 338, this sample may be referred to ly throughout this section. However, two zones could the upper early Miocene-middle Miocene. However, be identified, the Cycladophora davisiana Zone, ranging this is not accurate dating, as all other key species are throughout the Pleistocene, and the Antarctissa whitei missing. Zone, ranging throughout the Pliocene and slightly into

1116 RADIOLARIA

TABLE 16 TABLE 18 Pliocene-Pleistocene Samples Pre-Glacial Samples Barren Studied for Radiolarians — Site 345 for Radiolarians - Site 345

Core Section Interval (cm) Interval Core Sectioni (cm) 1 1 0-2 1 1 103-105 5 1 88-90 1 2 65-67 5 2 66-68 1 3 52-54 5 3 35-37 1 4 71-73 5 4 11-13 1 CC 5 4 105-107 2 1 49-51 5 CC 2 1 69-71 10 6 30-32 2 2 47-49 10 CC 2 2 94-96 11 1 30-32 2 3 44-46 11 2 20-22 2 3 109-111 11 3 35-37 2 CC 11 4 30-31 3 1 106-108 11 5 30-32 3 2 82-84 11 6 20-22 3 3 39-41 11 CC 3 3 129-131 Cores 12-30, Core-catcher 3 CC samples 4 I 60-62 4 2 52-54 CC

SITE 346 c c o >, -2 '43 TABLE 17 >, en S- 3 s- o ro js Selected Radiolarians from Site 345 Φ i— i— •r- > o o s- Depth 2!S 5 Φ 5 "^ Radiolarian (m) (SS ü 5* 5x3 zonation IHIIII•IIIIIIII I A/G ! Cyaladophora davisiana B Plio . Plei . Glacia l mu d CO S si R/M •S < •§ c-•s - 50 K d T••• ft, 1 d Unzoned •8 1 a d •a. g d R/M (L> c o ε •5 fit U o

l s Silic . ooz e (Interval C o +«^ — 100 Terr , sand y mu d —j 1 CS ik ?? in cm) ,£> o s1 i 0 δ a 0 < 0. 01 i. IH & I 1 fi tS ?? 6-1, 43-45 R P R 6-1, 80-82 R P - 150 6-1, 126-128 F P R Barre n

6-2, 17-19 C G R R F R Eocen e 6-2, 96-98 A M A F F

F Terr , mud sand y mu d 6, CC A G R A F F A R 7-2, 88-90 C G A R F R R R Figure 13. Site summary - Site 346. 7, CC R P R R 8-1, 125-127 C M R R R R R R R R 8-2, 118-120 C M F I F R the late Miocene. From Samples 12, CC to 18, CC there 8-3, 121-123 F M R R F is an unzoned interval, corresponding with a similar un- 8-4,58-60 F M R R R F zoned interval at Site 341. The mass occurrence of Hex- 8, CC C G R R F R C R F alonche sp. A is believed to be a good time indicator, 9-1, 141-143 R M R R and is present at Site 338 (Sample 7, CC), Site 341 9-2, 40-42 F M R R R (Sample 31-5, 17-19 cm), and Site 348 (Sample 15-2, 30- 9-3, 50-52 R M R R R 32 cm) of lower late Miocene. This site is also peculiar 9-4, 40-42 R P in having a high occurrence of phaeodarians in Samples 9, CC F M R R 5, CC through 7, CC (Plate 13, Figures 15-21). 10-0, 30-32 C G R R R R c 10-1, 35-37 C M c 10-2, 30-32 F M R R c F Ecological Interpretations 10-3, 45-47 F M R F From the site summaries (Figures 2-17), it was seen 10-4, 30-32 F M R F F that the "Glacial" sediments varied considerably in 10-5, 30-32 F M R F F thickness. It is of interest to observe that the "Glacial" sediments are principally barren of radiolarians at sites

1117 K. R. BJ0RKLUND

TABLE 19 Samples Studied for Radiolarians — Site 346 SITE 349 Φ C (O c o •— Core Section Interval (cm) ca •r- ^

O ro -Q +-> 1 1 Φ i— i— r- O 30-32a O O i- '— 1 CC Depth £ 8 5 Φ T3 to "αj Radiolarian 2 3 10-12 1 \ O Φ _i •=c et T3 < zonation 2 CC A/G Cyoladophora davisiana ••i c 3 3 130-132 Φ (J 3 CC O 4 2 95-97* 4 CCa Φ - 50 Q. 5 2 60-62a a 5 CC O 6 3 3O32a σ> a 6 CC _ o 7 3 35-37a 7 CCa a 8 3 25-27 1 O • CD O •r- 8 CC O r— LU O c 9 3 130-1323 Φ V. 9 CCa - 150 _l UJ 10 3 15-17a ca 10 CCa 11 3 95-97a 11 CCa 12 3 110-112 — 200 - 12 CC 13 3 20-22 Φ 13 CC U Cores 14-20, Core-catcher samples O - 250 Lu Φ aRadiolarians observed.

SITE 347 — 300 R/M Unzoned C O •i Figure 15. ^Ye summary - Site 349. Depth ^ w Radiolarian recover y Cor e Litholog y (m) Ag e S. T3 zonation respectively. The sediments have a relatively rich and Plei. A/G Cycladophova davisiana well-preserved radiolarian fauna. These radiolarian dis- tribution patterns are most likely explained by a com- bination of masking, dissolution, and production. For the Jan-Mayen area sites there is no nearby source of - 50 mu d terrigenous sediments, assuming that the sediments derived from Greenland are trapped on the western side sand y of the present spreading axis. However, on the V^ring Plateau and at the Knipovich Ridge, the buried V^ring

-100 rre n s mud , CO Plateau Escarpment and the Knipovich Ridge have trapped sediments being derived from Norway and the and Spitzbergen, respectively. Therefore, rigeno u the high influx of glacial-derived terrigenous material at Te r - 150 en e Sites 341 and 344 may be masking the radiolarians. It o should also be kept in mind that as a great deal of terrigenous material is put into suspension in the oceanic environment surface production might have Figure 14. Site summary - Site 347. been decreased. For the Jan-Mayen sites, as a consequence of the fact that most of the terrigenous sediments are trapped to located in the eastern and in the northern parts of the the west, the masking effect is less pronounced. The Norwegian Sea, Sites 341 and 344, having 323 meters water has less suspended material, allowing a higher and 320 meters of "Glacial" sediments, respectively. production, and therefore generally a better preserva- However, at most of the sites in the western part of the tion of siliceous microfossils in the sediments. Norwegian Sea (Sites 346, 347, 348, and 349), the Antarctissa whitei is generally rare in the eastern "Glacial" sediments average 50 meters in thickness, Norwegian Sea (Site 341), while it is abundant at Site varying from 32 to 64 meters at Sites 346 and 348, 348 in the western Norwegian Sea. This might indicate

1118 RADIOLARIA

SITE 348 SITE 350 Φ rπ E s= o i— c o fO i- >> S- ^ >, S_ 3 "§ >> o S- cu o O S- Φ i •r— o o > o o s- Depth cu o ^3 cu >> -St! Radiolarian 1 Depth £ S Φ "D LO Φ Radiolarian O S- < E c2 T3 zonation cn rα r- (m) ü > davisiana B ••• O T3 σ> 1 - 50 ro c cp s- c CU to R/M - 50 Φ fC O r- °- 1— c/) •r- Φ cTcI C/G F/M a αi C/G -100

h- CO _l O ε -200 •L o3 •r- R/P E: S: ••• C/G Unzoned o Φ c Φ S- Φ C Φ - 250 •£ £ O

- 250 -_, — 300 •

Φ T3 O ü> ε Φ CU -σ — 300 MM o Φ ^^rθ C - 350 CO s; Φ cu O >> -σ t- 1 HL ε « h- Φ <—1 π3 o et - 350 CO -400 __ σi "E Figure 16. Site summary - Site 350. h-

- 450 — that A. whitei is associated with cold water, and therefore, reflects a cold water current system in the o western Norwegian Sea. This system, only to some ex- tent, influences the radiolarian distribution further east Figure 17. 5/fó summary - Site 348. in the Norwegian Sea. The preglacial sediments again show an interesting terpreted as a transportation effect from the north distribution pattern. All sites in the Icelandic Plateau Atlantic water-masses which at this time got free access and Jan-Mayen area are characterized by being almost to the Norwegian Sea. barren, or by having rare radiolarians of moderate to As learned from Sites 338 and 342, only traces of key poor preservation. However, in the V^ring Plateau, species of importance for the lower latitude radiolarian preglacial sediments are characterized by rich faunas of zonation were observed. This is taken as evidence that a good preservation. This distribution pattern is a result faunal transportation by the North Atlantic Current, of active spreading and a high input of terrigenous from the North Atlantic into the Norwegian Sea, was material causing a suspension of loaded water. This, in very limited. Therefore, biogenic siliceous oozes that effect, reduced the productivity in the western Nor- accumulated in the Norwegian Sea, are concluded to wegian Sea during most of the Oligocene and Miocene. have been produced by a native fauna and flora. The The eastern Norwegian Sea is receiving limited well developed Eocene siliceous oozes on the V^ring amounts of terrigenous sediments, and is accumulating Plateau present another problem. What was the circula- biogenic siliceous oozes. tion system in the Norwegian Sea during the Eocene? The submergence of the Iceland-Faeroe Ridge is be- There was apparently no connection with the Atlantic lieved to have been definite in the lower early Miocene, Ocean to the south, but fauna similarities between the as the occurrence of Velicucullus oddgurneri and Cyrto- V^ring Plateau and different wells in Siberia (Kozlova capsella tetrapera in the Norwegian Sea sediments is in- and Gorbovetz, 1966) leads to the conclusion that the

1119 K. R. BJ0RKLUND

TABLE 20 TABLE 21 Pliocene-Pleistocene Samples Radiolarian Species, Abundances Studied for Radiolarians - Site 348 and Preservation - Site 348 Core Section Interval (cm)

1 1 65-67a 1 2 iakae 85-87a "5 M 1 3 75-77 T3