radiolaria - Marum

Bibliography - 1992 Radiolaria 14
older part of, the Dictyomitrella(?) kamoensis-Pantanellium
foveatum assemblage zone.
Nagai, H. & Zhu, S. 1992. Permian Radiolaria from the
Gufeng formation of Anhui Province and the Dalong
formation of the Nanjing Area, China. Bull. Nagoya Univ.
Furukawa Mus., 8, 1-11.
Permian radiolarians were extracted from chert samples
collected in the Gufeng Formation of Anhui Province and the Dalong
Formation of the Nanjing area in China. The radiolarian assemblage in
the former sample includes abundant Pseudoalbaillella fusiformis
Holdsworth and Jones, assignable to the Middle Permian, The latter
one includes Hegleria ? sp., Octatormentum ? sp., Pseudoalbaillella
sp. aff. P. longicornis Ishiga and Imoto, and Latentifistula sp cf. L
patagilaterala Nazarov and Ormiston, and they are Late Permian in
age.
Nanayama, F. 1992. Stratigraphy and facies of the
Paleocene Nakanogawa Group in the southern part of central
Hokkaido, Japan. J. geol. Soc. Japan, 98/11, 1041-1059.
(in Japanese)
Nigrini, C. & Caulet, J.P. 1992. Late Neogene
radiolarian assemblages characteristic of Indo-Pacific areas of
upwelling. Micropaleontology, 38/2, 139-164.
Comparison of radiolarian faunas in Late Neogene sediments
from the Peru margin, the Oman margin and from beneath the
Somalian gyres allowed definition of an assemblage characteristic of
areas of upwelling. We describe the stratigraphic and geographic
ranges of 12 previously studied and 10 new or newly described taxa.
These forms fall into 3 categories: (1) endemic upwelling (14
species); (2) displaced temperate (3 species); and (3) enhanced
tropical (5 species). Not all elements of the assemblage are present,
or in like abundances, in each upwelling area studied, but there is
sufficient matching to allow identification of the assemblage. Eight
long ranging species exhibit diachronous first appearances up to 7
my older in the Oman material than in the Peru material.
Nishimura, A. 1992. Paleocene radiolarian
biostratigraphy in the northwest Atlantic at Site 384, Leg 43,
of the Deep Sea Drilling Project. Micropaleontology, 38/4,
317-362.
Two zones, Bekoma campechensis and B. bidartensis Zones,
were recognized and three new subzones, Peritiviator (?) dumitricai,
Orbula discipulus and Stylotrochus nitidus-Pterocodon (?) poculum
Subzones are newly defined based on the Paleocene samples from
DSDP Site 384. A new genus and 35 new taxa are described herein.
Nishimura, A.A. & Ikehara, K. 1992. Deep-Sea
sediments in the southern part of the central Pacific basin
(GH82-4 area). Geol. Surv. Japan, Cruise Rep., 22, 85-96.
(in Japanese)
During the GH82-4 Cruise, areal distribution of sediments and
sedimentary history were studied in the south of the Nova-Canton
Trough, central Equatorial Pacific (Fig. VI-1) in relation to the
genesis of manganese nodules. A small area was selected for smallscale
sampling in the eastern margin of the whole survey area (Fig.
VI-2). Sampling methods of sediments and manganese nodules are
as follows; double spades box corer (15 sites), piston corer (20
sites), and free-fall grab with a small sediment sampler (39 sites).
Box and piston core sites are shown in Tables VI-1 and Vl-2 and in
Figures VI-I and VI-2. Sediments collected by a box corer, piston
corer, and free-fall grab sampler were treated in the same manner as
in previous works (Nishimura, 1984 and 1986). Sediment lithology
was classified according to the compositions of sediments
determined on smear slides under a microscope. The framework of
sediment classification is shown in Table VI-3. Age estimation of the
core sequences are based on preliminary micropaleontologic
analysis and a study of remnant magnetism of sediments (Yamazaki,
chapter Vll of this volume). This chapter describes lithology of
sediments and discusses sedimentary history concerning surface
sediments and core sequences.
Noble, P. 1992. Biostratigraphy of the Caballos
Novaculaite-Tesnus Formation boundary, Marathon Basin,
Texas. In: Significance and application of Radiolaria to
terrane analysis. (Aitchison, J.C. & Murchey, B.L., Eds.),
vol. 96/1-2. Special Issue: Palaeogeogr. Palaeoclimatol.
Palaeoecol., Elsevier, Amsterdam. pp. 141-153.
The Caballos Novaculite is a radiolarian/sponge spicule chert
and siliceous mudstone which represents the final episode of a 200
- 86 -
Ma span of dominantly biogenous hemipelagic sedimentation in
Marathon Basin. It is overlain by the Tesnus Formation, an upwardcoarsening
flysch sequence produced during the Ouachita Orogeny
by the collision of Laurasia and Gondwana. Detailed radiolarian
biostratigraphy of the boundary between these two units has
provided greater age control as to the onset of flysch deposition and
provides a greater understanding of the sedimentary patterns
produced in Ouachita basinal facies when switching modes of
sedimentation from a passive to an active regime. Radiolarians and
conodonts recovered from this interval show a hiatus equivalent to
much of the Early Mississippian occurring in the vicinity of the
boundary between the Caballos and Tesnus formations. In three
sections, Late Mississippian (Meramecian) radiolarians overlie
earliest Mississippian (early Kinderhookian) radiolarians in an
apparently conformable sequence of siliceous shale. In a fourth
section, Meramecian radiolarians overlie Late Devonian (Famennian)
radiolarians and conodonts, separated by a conglomerate layer.
These data indicate that a hiatus equivalent to the late
Kinderhookian to Osagean time period is present and that local
erosion into the Famennian part of the section occurred.
Lithostratigraphically, this hiatus is coincident with the
Caballos Novaculite-Tesnus Formation boundary in the central part
of the basin, while at the western margin, it occurs 8 m above the
base of the Tesnus Formation, immediately above a clastic zone
containing olistoliths. Results from this investigation show that
localized deposition of olistoliths occurred in the western basin
margin during the Famennian (Late Devonian), followed by an interval
of non-deposition in the Early Mississippian. Finally, basin-wide
flysch deposition began in the Meramecian.
Ogawa, Y., Ashi, J. & Fujioka, K. 1992. Vein
structures and their tectonic implications for the development
of the Izu-Bonin forearc, Leg 126. In: Proceedings of the
Ocean Drilling Program, Scientific Results. (Taylor, B.,
Fujioka, K. et al., Eds.), vol. 126. College Station, TX
(Ocean Drilling Program), pp. 195-207.
Samples with vein structures were taken from Sites 787 and
793 in the forearc basin of the Izu-Bonin island arc off Aoga Shima
and Sumisu Jima, respectively, between the present volcanic front
and me outer arc high. The samples were studied by thin section, Xray
radiograph, and magnetometer; they are discussed with respect
to the tectonic implication of the vein structures to the island-arc
development. Vein structures are developed in finer, more clayey,
preferentially radiolarian-bearing mudstone, subvertical to the
bedding plane, which is mostly horizontal. The veins are restricted to
certain horizons: in the upper Oligocene at Site 787 and in the lower
Miocene at Site 793. The veins are filled with a dominant clay
mineral (montmorillonite), which flowed into the vein when the
fracture and concomitant stress drop occurred. Some clay mineral
was deposited from the fluid that invaded the vein. Some veins might
have occurred as hydraulic fractures. The shape, mode of
occurrence, and other structural features indicate that the veins
originated either as extension fractures or shear cleavages, and
then were rotated by the following shearing parallel to the bedding.
Sometimes the bedding-parallel slip planes are dislocated by the
veins, and sometimes vice versa. This suggests that the vein
formation and bedding parallel slip alternately occurred within the
same stress environment. Vein attitude was measured by a
magnetometer, after alternating field demagnetization; we interpret
that they originally formed as subvertical planes, the trends of which
average to N45W. The quantity of samples studied was small, but
the trends suggest that the stress field for veining might have had a
relative extensional stress axis mat lay subhorizontally and trended
generally northeast. This stress orientation might be attributed to
either bending or normal faulting in the forearc basin, at a time when
the arc trended northwest.
Ogawa, Y., Nishiyama, T., Obata, M., Nishi, T.,
Miyazaki, K., Ikeda, T., Yoshimura, Y. &
Nagakawa, K. 1992. Continental margin tectonics in
Kyushu, southwest Japan- Mesozoic paired metamorphic
belts and accretionary complexes. In: Paleozoic and
Mesozoic Terranes: Basement of the Japanese Island Arcs.
29th IGC Field Trip Guide Book. (Adachi, M. & Suzuki, K.,
Eds.), vol. 1. Nagoya University, Nagoya, Japan. pp. 261-
315.
Ogg, J.G., Karl, S.M. & Behl, R.J. 1992. Jurassic
through Early Cretaceous sedimentation history of the central
equatorial Pacific and of Sites 800 and 801. In: Proceedings of
the Ocean Drilling Program, Scientific Results. (Larsen, R.L.,
Lancelot, Y. et al., Eds.), vol. 129. College Station, TX
(Ocean Drilling Program), pp. 571-613.
Sedimentation in the central Pacific during the Jurassic and
Early Cretaceous was dominated by abundant biogenic silica. A