‘Amber’ is a general term used to describe the fossilised resin of trees. It is most familiar as a precious substance used for jewellery, but also highly prized by scientists and collectors because it sometimes contains the remains of small invertebrate animals, including insects, mites and spiders. It may also contain plants, fungi and, rarely, small vertebrate animals or evidence of them, such as hairs or feathers.
Acacia flowers (2014) by Geoff Thompson, Queensland MuseumQueensland Museum Network
Amber is rare in the fossil record of
Australia, but small amounts are known from the Cenozoic-aged coals and lignites in
Victoria and Tasmania and from older Cretaceous sites. A fossil spider has also
been described from fossil resin in Victoria. Despite these examples, when
amber like material was discovered on a distant beach on Cape York in 2003, it
was initially dismissed by some researchers as having been misidentified.
The Cape York amber includes tiny insects and plant material, including flowers, such as the group of Acacia-like flowers.
The source tree of the Cape York amber is not known. It was initially thought to be a conifer, perhaps related to hoop pine of Kauri Pine (Araucariaceae), but while Kauri Pines occur in Australia, the evidence for this identification is inconclusive. Most recently, it has been suggested that the amber may be from the flowering plant family, Dipterocarpaceae. However, although this family occurs in Indonesia and Papua New Guinea, it is not found in Australia and there is no fossil record of it from this continent. For this reason, it has been suggested that the amber may have been carried on ocean currents to the Cape York area. As the amber has been found in lignites on Cape York, this indicates that the source of trees were growing locally.
The uncertainty about the botanical origin of the Cape York amber may seem surprising, but the source trees of Baltic amber from northern Europe, (the most studied and largest deposits of fossil resin on Earth), are still being debated. Recent detailed research, using infrared spectroscopy and the study of conifer leaves occurring in the amber, suggests the source trees of Baltic amber were conifers of the family Sciadopityaceae. Today, this group is represented by a single surviving species, the Japanese Umbrella Pine, Sciadopitys verticillata.
The amber from Cape York is translucent to opaque and comes in many colours, including red, yellow and fluorescent blue. Interestingly, some of the Cape York amber has been bored by molluscs, which indicates it has been in the sea for an extended period of time. It is possible that the source of the amber lies offshore in beds of sedimentary rock on the sea floor. The age of the amber also remains uncertain but, it is thought to be Miocene (23-5.3 million years ago).
Diptera (2014) by Geoff Thompson, Queensland MuseumQueensland Museum Network
Diptera, Cape York Amber Collection
Phanuromyia sp.(Platygastridae s.l.: Telenominae) (2015) by Geoff Thompson, Queensland MuseumQueensland Museum Network
Wasp in Dark Cape York Amber
Salticidae (2014) by Geoff Thompson, Queensland MuseumQueensland Museum Network
Jumping spider in Cape York Amber
Images and text from: In Search of Ancient Queensland.
Principal Authors: Dr Alex Cook and Dr Andrew Rozefelds.
Published by the Queensland Museum, 2015.
Photographers: Geoff Thompson, Paul Tierney
The Queensland Museum has been able to acquire and carry out research on the Cape York amber thanks to the generous support of Queensland Museum Foundation donors, Phil Creaser and Paul and Sue Taylor.