OFR 151.pdf - CRC LEME

6. TIME SLICE K-6
Age Range: Late Campanian-Maastrichtian [~70-65 Ma]
Zones: Tricolporites lilliei to Forcipites longus Zones
Isabelidinium korojonense to Manumiella druggii Zones
6.1 Macrofossil Floras
Unidentified plant cuticle usually is a major component in microfossil preparations.
6.2 Microfossil Floras
Tricolporites lilliei and/or Forcipites longus Zone palynofloras are preserved in the offshore
basins along the southern and northwestern margins and, less commonly, in central Australia.
These provide evidence for massive adaptive radiation of the Proteaceae during the Late
Campanian, and a marked north to south provincialism in the composition of the dryland
vegetation during the Maastrichtian.
Examples of species that are common to abundant along the southern margin but only
sporadically recorded in correlative microfloras from northern and central Australia are:
Dacrycarpus (Dacrycarpites australiensis), Dacrydium (Lygistepollenites balmei, L. florinii),
Lagarostrobos, Agathis/Wollemia (Dilwynites), Gambierina and Nothofagidites senectus.
Many of these taxa first evolved or migrated into Australia from high latitude remnants of
western Gondwana during the Campanian and it is reasonable to assume that all had strong
preferences for humid-perhumid habitats and were adapted to seasonally cool-cold
(microtherm range) temperatures and low light intensities. However the relative abundance
of ancestral Nothofagus remains the primary indicator of seasonal humidity.
Fossil pollen types that are extremely rare (or absent) on the southern margin but which
routinely occur in the North West Shelf assemblages include a robust variant of Tricolporites
lilliei (Neoscortechinia-type), Longapertites (Palmae), Integricorpus (Triprojectacites), and
Anacolosidites sp. cf. A. acutullus (Anacolosa). Most of these have NLRs that are confined to
coastal and/or wet forest types in tropical Africa, Madagascar and Asia and it is reasonable to
assume that the taxa indicate seasonally warm (mesotherm range) and seasonally perhumid
(possibly monsoonal) conditions.
This conclusion is supported by distribution data. For example, Anacolosidites and
Integricorpus do not reach the southern margin basins until the Palaeogene whilst
Longapertites is not recorded south of central Australia. One fossil spore type which first
appears in the Campanian (Cyathidites splendens) is nearly identical to spores produced by
the tropical mangrove fern Acrostichum aureum, although it is premature to assume the taxon
is evidence for saline environments.
Many northern microfloras include significant numbers of very small (