Catalog - Globoquadrina asanoi

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Globoquadrina asanoi

Citation: Globoquadrina asanoi Maiya, Saito, & Sato 1976

Type sample (& lithostrat): sample N-N-1. Nomura Mudstone Member, the upper part of the Funakawa Formation;

Type locality: Sea-cliff on the northern coast of Oga Peninsula, about 500 m, NE of Nomura, Oga City, Akita Prefecture, NW Japan

Type repository: Tokyo, Japan; National Science Museum

Test free, coiled in a low trochospire with 10 to 11 chambers in all, arranged in about two and one-half whorls, usually four in the final whorl; earlier whorls prominently high trochospiral, protruding conically on the spiral side; chambers subspherical or ovate, strongly inflated, gently embracing one another, gradually increasing in size as added; equatorial profile broadly subrhomboidal, moderately lobulate equatorial periphery, axial periphery subelliptical, broadly rounded; sutures of the umbilical side strongly depressed, almost becoming incised toward umbilicus, radial to gently curved; sutures on the spiral side almost indistinct in the earlier whorls, but becoming radial to slightly curved in the last whorl, slightly depressed; umbilicus distinct deep and widely open, roughly subquadrate opening; aperture interiomarginal, umbilical, lowarched, with no apparent apertural modification; wall calcareous, coarsely pitted.

Holotype (plate 3, figures 1 a- 1 c) 0.69 mm.; paratype (plate 3, figures 2a-2c. 3) 0.60 mm.; other unfigured paratypes range from 0.60 mm, to 0.69 mm.

Globigerina conglomerata Schwager.-TAKAYANAGI and SAITO, 1962, p. 84, pi. 24, figs. 10a-c. Not Globigerina conglomerata Schwager. 1866.

Remarks: In general appearance, this species somewhat resembles Globoquadrina conglomerata (Schwager). lt is distinguished from the latter, however, by its conspicuously protruding conical arrangement of the earlier chambers on the spiral side and by its more globular, inflated chambers. lt also differs from G. conglomerata in having a more lobulate equatorial profile and more narrowly opened umbilicus. The specimen described as G. conglomerata by Takayanagi and Saito (1962) from the Nobori Formation. Shikoku. Japan, is here referred to as G. asanoi because of its globular, inflated chambers and the high conical arrangement of the earlier whorls. Saito (1963) reported the occurrence of this species in Tsuchizaki R-7 well, drilled at latitude 39" 45' 41" N ., longitude 140" 03' E ., northwest of Akita City, Akita Prefecture, under the specific name of G. conglomerata.

Occurrences: This species ranges from the middle part of the Gauss Epoch to the base of the Olduvai Event in North Pacific deep-sea cores ( RC1 0-161. RC1 0-164) . In the oil-producing region of Japan, it is restricted to the Globigerina pachyderma (dextral) I Globorotalia orientalis Zone, lt occurs abundantly in the upper part of the Funakawa Formation (Nomura Mudstone Member) of the Oga Peninsula, in the middle part of the Tentokuji Formation of the Akita oil field, and in the middle part of the Nishiyama Formation.

References:

Maiya, S., Saito, T. & Sato, T. (1976). Late Cenozoic planktonic foraminiferal biostratigraphy of northwest Pacific sedimentary sequences. In, Takayanagi, Y. & Saito, T. (eds) Progress in Micropaleontology. Micropaleontology Press, New York 395-422. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globoquadrina asanoi Maiya, Saito, & Sato 1976

Globoquadrina asanoi

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