Stratigraphy and vertebrate fauna of the Otibanda Formation, New Guinea  

Authors / CoAuthors

Plane, M.D.

Abstract

Late Tertiary intermontane lacustrine and fluviatile deposits in the Morobe District of New Guinea contain vertebrate fossils in association with dated pyroclastic rocks. Metamorphic rocks ranging in age from probable Palaeozoic to middle or late Cretaceous form a complex basement into which granodiorite plutons were intruded in the late Cretaceous or early Tertiary. From probable Oligocene or Miocene time porphyritic rocks intruded the metamorphics and granodiorite; this activity culminated in explosive vulcanism which produced vast quantities of agglomerate. The agglomerate blocked the drainages, and lacustrine and laterally restricted floodplain deposits formed behind the dams during the Pliocene. A formation, the Otibanda Formation, which includes lacustrine sediments, f100dplain deposits, and interbedded tuffs is formally defined. Its thickness cannot be estimated, but a measured section is more than 2500 feet thick. The type section at 'Sunshine' contains fossiliferous sandstone and mudstone with conglomerate and intercalated pyroclastic rocks which yield Potassium/Argon dates from below the mammal horizons of 6.1 and 7.6 million years. A 5.7 million year date higher in the section is associated with the type faunal locality, which has produced an incisor of the earliest known rodent from the Australian region and new representatives of the marsupial families Ma«ropodidae and Diprotodontidae. The fauna also includes gastropods, crocodilians, snakes, birds, and a dasyurid. Fossil vertebrates have been collected from 21 widely scattered localities.

Product Type

document

eCat Id

165

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Keywords

• GA PublicationBulletin

( Theme )

• stratigraphy

• PG

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_External

Publication Date

1967-01-01T00:00:00

Creation Date

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Access - license

Use - license

Status

Purpose

Maintenance Information

unknown

Topic Category

geoscientificInformation

Series Information

Bulletin 086

Lineage

Unknown

Parent Information

Extents

[-7.0, -5.0, 144.0, 145.5]

Reference System

Spatial Resolution

Service Information

Associations

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Download the Bulletin (pdf)  

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