radiolaria - Marum

Radiolaria 14 Bibliography - 1992
northwestern British Columbia. Geol. Surv. Canada, curr.
res., Pap., 92-1E, 107-116.
Nine age-diagnostic microfossil collections from the Stikine
terrane in northwestern British Columbia confirm the presence and
extend the distribution of several regionally mappable geological
units; they also place constraints on the timing of early Mesozoic
deformation affecting western Stikine terrane. Radiolarians are Early
Permian, Late Triassic, and Middle Jurassic in age, spanning a large
part of the stratigraphic range of Stikine terrane, and are found in
various lithologies, including siliceous siltstone, limestone, and
bedded chert. Conodonts are from carbonate and are Late Triassic
(Late Carnian, Late Norian) in age.
Cordey, F. & Read, P.B. 1992. Permian and Triassic
radiolarian ages from the Cache Creek Complex, Dog Creek
and Alkali Lake areas, southwestern British Columbia. Geol.
Surv. Canada, curr. res., Pap., 92-1E, 41-51.
Ten radiolarian chert localities from the Cache Creek Complex
on both sides of the Fraser Fault in Dog Creek and Alkali Lake areas
range in age from Early Permian (late Asselian-late Sakmarian)
through Middle Triassic (late Anisian-early Ladinian) to Late Triassic
(Early Carnian, Early-Middle Norian, Late Norian). This age range is
similar to that of the Cache Creek cherts in their type locality, 150
km to the south. The newly discovered localities come from one or
more slices of the complex which were thrust northeastward over
Early Jurassic rocks. Chert-bearing units underlie undated clastic
rocks that may represent a regional(?) overlap assemblage.
Diester-Haass, L., Meyers, P.A. & Rothe, P.
1992. The Benguela Current and associated upwelling on the
southwest African Margin: a synthesis of the Neogene-
Quaternary sedimentary record at DSDP sites 362 and 532. In:
Upwelling Systems: Evolution Since the Early Miocene.
(Summerhayes, C.P., Prell, W.L. & Emeis, K.C., Eds.), vol.
64. Geological Society of London, special Publication,
London, U.K. pp. 331-342.
Sediments cored at DSDP Sites 362 and 532 on the Walvis
Ridge provide a Neogene-Quaternary history of the development of
the upwelling system on the south-west African margin. Upwelling
occurs principally on the landward side of the Benguela Current. The
upwelling centres have shifted northward since the Middle Miocene
as the current has intensified and has flowed farther to the north.
Changes in productivity are recorded in the types, proportions and
preservation of foraminifera, radiolaria, diatoms, organic matter, and
clay minerals in the sedimentary record. Prior to the Late Miocene
(10 Ma), the Benguela Current did not reach the Walvis Ridge, and
enhanced productivity is not evident in the sediments at this
location. Between 10 to 5.2 Ma, upwelling was recorded in the DSDP
sites in glacial periods, indicating that the Benguela Current
intensified during glacial periods and transported evidence of
upwelling to Sites 362/532 from near-coastal areas. During
interglacial periods the current was not as strong and did not reach
the Walvis Ridge, turning instead to the west within the Cape Basin.
Strengthening of the current continued such that by the Pliocene and
Quarternary the upwelling signal is contained in interglacial
sediments. Sediments deposited in these more recent glacial times
contain a weak or absent upwelling signal because glacial
intensification shifts the Benguela Current system northward to
reach the Angola Basin before it turns westward away from its
coast-parallel direction.
El Kadiri, K. 1992. Description de nouvelles espèces de
radiolaires jurassiques de la Dorsale calcaire externe (Rif,
Maroc). Rev. españ. Paleont., Núm. Extra., 37-48.
The study of radiolaria obtained from the bottom of the Jurassic
radiolarian beds in the Rif "Dorsale calcaire externe" display the
study of some new species. Some one and two new genres are
described here. The presence of ammonites in the bottom of that
facies and the inmediately in the lower beds attribute an Upper Lias
or Lower Dogger age to the siliceous micro-faune recolted.
El Kadiri, K., Linares, A. & Olóriz, F. 1992. La
Dorsale Calcaire rifaine (Maroc septentrional): Evolution
stratigraphique et géodynamique durant le Jurassique-Crétacé.
Notes Mém. Serv géol. Maroc, 366, 217-265.
The reduced Jurassic-Cretaceous series of the "Dorsale
calcaire" with facies of ammonitico-rosso type and radiolarites are
dated by the main chronological markers: ammonites, Radiolaria,
Calpionellids and Foraminifera. The stratigraphic and geodynamic
evolution of the "Dorsale interne" appears to be clearly different
from that of the "Dorsale externe". In the first one, significant
episodes of emersion-karstification are made evident during the
Carixian, Dogger-Malm p.p. and the Cretaceous p. p. During the time
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between these episodes a reduced sedimentation which is preserved
in the paleokarstic cavities is expressed in the form of: 1)
ammonitico-rosso facies during the Domerian-Toarcian, 2)
radiolarites during the upper kimmeridgian-lower Tithonian and 3)
ammonitico-rosso/bianco during the Tithonian. At the end of the
Cretaceous the sedimentation starts again by the deposition
olistostromes during the Campanian. While the Jurassic
sedimentation in the "Dorsale externe" remains almost continuous.
Moreover, these different facies appear early: ammonitico-rosso
facies from the end of the Hettangian and continue during the
Sinemurian; radiolarites from the upper Toarcian-Aalenian. The
Olistostromes appear from the lower Cretaceous.
These reduced series which have to do with a subsiding
continental margin show that the "Dorsale interne" and "Dorsale
externe" correspond respectively: 1) to one or several half-grabens
tilted towards the internal side of the margin and 2) to crustal
blocks located at distal position. The relative movement of the
internal half-grabens in relation to the external blocks leads us to
put forward a kinematic model for the dynamics of the subsiding
continental margin: the movement of the balance. The global context
of this movement was the normal shearing of the crust.
The application of this model to the westhern front of the
Alboran plate (Rif) allows us to propose the existence of: 1) a basal
intralithospheric fault at the old boundary between the internal and
the external Zones diping towards the East, and 2) an astenospheric
dome which emerges below the Alboran plate starting from the lower
Lias.
Feng, Q. 1992. Permian and Triassic radiolarian
biostratigraphy in south and southwest China. Earth Sci., J.
China Univ. Geosci., 3/1, 51-62.
The study of Permian radiolarians in South and Southwest China
has been advanced in recent years . A well—preserved radiolarian
fauna of Triassic is recently found in Southwest China. Eight
radiolarian assemblage zones are recognized as follows in ascending
order: Pseudoalbaillella rhombothoracata assemblage zone (Qixian),
Pseudoalbaillella fusiformis assemblage zone (early—middle
Maokouan), Follicucullus assemblage zone (late Maokouan-
Wujiapingian). Cangyuanella assemblage zone (early—middle
Changxingian), Clavata assemblage zone (latest Permian),
Triassocampe yini assemblage zone (early Early Triassic),
Pseudoeucyrtis liui assemblage zone (late Early Triassic) and
Triassocampe deweveri assemblage zone (Middle Triassic) .The
Permo—Triassic boundary in chert mono—facial sequence of the
Muyinhe Formation is discussed.
Goto, H., Umeda, M. & Ishiga, H. 1992. Late
Ordovician Radiolarians from the Lachlan Fold Belt,
Southeastern Australia. Mem. Fac. Sci., Shimane Univ., 26,
145-170.
Gowing, M.M. & Garrison, D.L. 1992. Abundance
and feeding ecology of larger protozooplankton in the iceedge
zone of the Weddell and Scotia Seas during the austral
winter. Deep-Sea Res. Part A, oceanogr. Res. Pap., 39, 893-
919.
Biomass abundances and feeding ecology of larger (>50µm
diameter) protozoo plankton were studied in the upper 210 m in the
ice edge zone of the Weddell/Scotia Sea area in the austral winter of
1988. Sixty -liter water samples were taken at five depths at 17
stations, and organisms were concentrated by reverse flowfiltration.
Mean abundances of the total assemblages of larger
protozooplankton (radiolarians, foraminiferans, acantharian, the
heliozoan Sticholonche, tintinnid and aloricate ciliates, and thecate
and athecate dinoflagellates) ranged from 2040 to 3745 m -3 in the
upper 210m. Biomass ranged from 33 to 48 µg C m -3 in the upper
85 m, and from 32 to 54 µg C m -3 from 115 to 210 m. Phaeodarian
radiolarians larger than 1.6 mm (sampled with plummet nets)
contributed an additional 3 µg C m -3 in the upper 100 m and an
additional 7 µg C m -3 from 100 to 200 m. These abundances and
biomasses are lower than for other seasons in the Antarctic, but are
comparable to abundances reported for several of these groups in
lower latitude waters. We attribute the low winter abundances to
slower growth and reduced food, rather than to increased mortality.
The large protozooplankton are trophically diverse; in addition to
heterotrophy on a variety of organisms, we found apparent evidence
of mixotrophy and symbiosis in some of the groups. The large
protozooplankton fed on both autotrophic and heterotrophic
organisms in winter, although the biomass of smaller forms is
dominated by heterotrophs. Feeding on detrital particles also was
indicated by the presence of siliceous fragments in vacuoles. The
larger particles also was indicated by the presence of siliceous
fragments in vacuoles. The larger protozooplankton in the winter ice
edge zone may be important in reducing particle flux to the deep sea
and as a food source for larger zooplankton, especially form the
base of the euphotic zone to 210 m.