Campbell - Kaikorai Leaf Bed megafossils

skip to content skip to navigtion accessibility statement

Home < Publications < Our Journals < New Zealand Journal of Botany < 1985

New Zealand Journal of Botany abstracts

Casuarinaceae, Fagaceae, and other plant megafossils from Kaikorai Leaf Beds (Miocene) Kaikorai Valley, Dunedin, New Zealand

J. D. CAMPBELL

Department of Geology, University of Otago
P.O. Box 56, Dunedin, New Zealand

Abstract Fruiting cones (infructescences) of Casuarinaceae and fruits of more than five further angiosperms are preserved in diatomite at Frasers Gully, Kaikorai Valley, Dunedin district. The flo- ral assemblage also includes possible immature cones of Casuarinaceae, and many leaves. The majority of the leaves belong to Fagaceae but Pro- teaceae and other families are present. The beech leaf fossils for which the form-genus Nothofaga- phyllites is proposed are all denticulate and acu- minate. They include rare notophylls but most are large microphylls. Their secondary veins are regu- larly spaced, straight, or slightly curved. Tertiaries are orthogonal reticulate or percurrent forked. Cuticular details are unknown. Leaf form is remi- niscent of living New Caledonian species of Notho- fagus with which one of the fossil fruits is also compared. All Fagaceae fossils from the deposit show some affinities with the brassii (pollen) sec- tion of Nothofagus. Kaikorai Leaf Beds are a lacustrine deposit within the Dunedin Volcanic Complex of Miocene age (Waiauan local stage at the base) within the range 10-13 Ma.

Keywords Casuarinaceae; Fagaceae; Notho- fagus; Nothofagaphyllites; Carpolithus; Proteaceae; Kaikorai Leaf Beds; Dunedin Volcanic Complex; Miocene of plant fossils, no fructifications were described. Along with leaves, the fruiting cones and fruits reported here were found recently in the course of recollection in the section from which Oliver's material came. The beds from which the new col- lection was made are exposed in earthworks asso- ciated with the construction of a foot bridge over Frasers Stream. Collecting was done through a sec- tion of about 1 m. The beds have a very low sea- ward dip. The dominant lithology is white- weathering diatomite which is moderately well laminated. Some horizons show bioturbation. Terminology of leaf form follows Dilcher (1974), that of leaf size derives from Webb (1959). STRATIGRAPHIC SETTING Benson (1959) used the term Kaikorai Leaf Beds for that part of his Older Flood Plain Conglom- erate with leaf fossils. The sediments were consid- ered by him to have accumulated in "shallow synclinal valleys" during a phase of explosive erup- tion within Dunedin petrographic province. Oliver (1936) and Benson (1959, 1968) recorded the occurrence in the leaf beds at Frasers Gully of diatoms mostly of the Melosira group and spicules of a fresh-water sponge. The fish Galaxias brevi- pinnis Gunther was recorded from Frasers Gully by McDowall (1976) in the course of a review of the species G. kaikorai Whitley (1956) erected for fossil material collected by G. S. Thomson and housed in the Geology Department, University of Otago (see also Stokell 1945, Whitley 1956).

PDF file of entire paper: medium quality (1893K); (scanned from paper original: notes about this process)

This year's abstracts | Journal home page | All abstracts | Publishing home page