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Tertiary larger foraminifera from Guam

1963; United States Government Publishing Office; Linguagem: Inglês

10.3133/pp403e

2330-7102

William S. Cole,

Isotope Analysis in Ecology

The distribution and occurrence of larger Foraminifera ranging in age from Eocene, Tertiary b, to Pleistocene on Guam are given in this report.Species that have not been discussed in previous studies of this general area are illustrated and described in detail, but most of the well-known species are only listed.Twenty-one species were found in the Alutom Formation.These species, with the exception of Camerina fichteli which occurred at two localities, are known to be diagnostic of the Eocene, Tertiary b.Camerina fichteli is considered to be diagnostic of the Oligocene, Tertiary c and d, in the Malayan Archipelago.Certain localities on Guam, at which the limestone beds containing larger Foraminifera were known to be in their original position, and at which Camerina fichteli was not found, are assigned to Tertiary b.Other localities, at which Camerina fichteli was found in association with assumed reworked Tertiary b species, are assigned to Tertiary c. Certain other localities in the Alutom Formation could be either Eocene or Oligocene.The Maemong Limestone Member of the Umatac Formation, with a fauna of 18 species, is assigned to the Miocene, Tertiary e, and is divided into two paleontologic zones.This limestone correlates with the Tagpochau Limestone of Saipan.The Bolanos Pyroclastic Member, which overlies the Maemong Limestone Member, is either late Tertiary e or early Tertiary / (Miocene) in age, or both.The fauna obtained from boulders and matrix material in this conglomerate is the same as that from the Maemong Limestone Member.Fifteen species, of which all but one had been recorded previously from the Futuna Limestone of Lau, Fiji, were found in the Bonya Limestone of Tertiary / (Miocene) age.The lower part of the Alifan Limestone, in which Rotalia atjehensis and Miogypsinoides cupulaeformis were found, may correlate with the upper part of the Bonya Limestone or be slightly younger.The part of the Alifan Limestone that contains a Cycloclypeus-Operculina fauna may be still younger, and may be equivalent to the Barrigada Limestone of Tertiary g (Miocene) age.The Barrigada Limestone, which contained only three diagnostic species of larger Foraminifera, is assigned to Tertiary g (Miocene), because these species were found in drill holes on Bikini and Eniwetok Atolls in strata that were assumed to represent this stage.The fore-reef facies was the only part of the Mariana Limestone that contained recognizable larger Foraminifera.This facies, with abundant Calcarina spengleri, is Pleistocene or Recent in 3 C c Ii5 1 a Contains also reworked Eocene species: Camerina pengaronensis and Halkyardia bikiniensis.