The Miocene Era: A Time of Transformation in Earth's History
The Miocene Era (or Miocene Epoch) is one of the most important periods in Earth’s geological and biological history. Lasting from approximately 23 million to 5.3 million years ago, it was an era of dramatic environmental change, shaping the continents, oceans, and life forms we recognise today.
During the Miocene, mountain ranges rose, grasslands expanded, and climate cooling paved the way for modern ecosystems. For Australia — including what is now Victoria — this period was crucial. The continent drifted northward, its climate became drier, and its flora and fauna evolved toward the distinctive Australian biota we know today.
Geological Context
The Miocene is part of the Neogene Period, following the Oligocene Epoch and preceding the Pliocene. Tectonic activity continued to reshape the planet.
Global Geology
The Himalayas, Alps, and Andes were actively rising due to tectonic collisions (Scotese, 2015).
Volcanic activity increased in the Pacific Ring of Fire, influencing global climate.
Sea levels fluctuated as polar ice expanded and melted repeatedly.
Australia’s Position
Australia had fully separated from Antarctica by the early Miocene, continuing its northward drift (McGowran et al., 2004).
The separation intensified the Antarctic Circumpolar Current, leading to global cooling.
In Victoria, volcanic plains began forming — especially across the Western District — laying the groundwork for what became the largest volcanic field in the Southern Hemisphere (Joyce, 2010).
Climate and Environmental Change
The Miocene climate was a bridge between the warm, tropical conditions of earlier epochs and the cooler, more arid world of today.
Early Miocene
Warm and humid; forests dominated much of the Earth.
Sea levels were high, supporting extensive coastal wetlands.
Middle Miocene
The Middle Miocene Climatic Optimum (17–15 million years ago) brought brief warming, then a major cooling phase.
Antarctic ice sheets expanded, reducing sea levels and drying global climates (Zachos et al., 2001).
Late Miocene
Global cooling and drying intensified.
Grasslands replaced forests in many regions.
Deserts began forming in central Australia, marking the start of the continent’s modern aridity.
Life During the Miocene
Plants
The spread of grasses and flowering plants (angiosperms) transformed global ecosystems.
In Victoria, fossil evidence from Lorne, Torquay, and Gippsland shows the presence of rainforest flora, later replaced by open woodland species (Christophel & Greenwood, 1989).
Animals
Mammals diversified, including early ancestors of elephants, horses, camels, and apes.
In Australia, marsupials thrived — ancestors of modern kangaroos, wombats, and possums evolved in this period.
The Diprotodon, the world’s largest marsupial, had early relatives during the late Miocene.
Marine life also flourished — giant sharks like Carcharocles megalodon roamed ancient seas.
Birds and Reptiles
The Miocene saw the rise of large flightless birds (precursors to the emu and cassowary).
Crocodiles and snakes adapted to cooling, variable climates.
Miocene in Victoria
Victoria’s landscape bears many traces of Miocene activity:
Volcanic Activity: The Newer Volcanic Province, stretching from Ballarat to the Otways and Port Fairy, began erupting in the late Miocene, forming lava plains, cones, and maar craters (Joyce, 2010).
Marine Deposits: Miocene marine fossils found along the Otway and Mornington Peninsulas reveal ancient seas teeming with corals, shells, and whales.
Climate Shifts: The transition from lush Miocene rainforests to dry woodlands marks the beginning of Victoria’s modern ecology.
Great Dividing Range: Erosion during this era shaped valleys and rivers like the Moorabool and Barwon, foundational to later Aboriginal Country.
Human Evolution and the Miocene
Although humans did not yet exist, the Miocene was critical to our evolutionary story.
Early apes (hominoids) appeared in Africa about 20 million years ago, diverging from Old World monkeys (Begun, 2004).
By the late Miocene, several ape species — including Sahelanthropus tchadensis and Orrorin tugenensis — show traits leading toward the human lineage.
The changing climate and expanding grasslands of the Miocene may have driven bipedal adaptation.
Global Significance
The Miocene marked a transition toward modern ecosystems:
Formation of major deserts (Sahara, Australian interior).
Spread of grasslands and savannas, supporting grazing animals.
Establishment of modern ocean currents that shaped global weather patterns.
Evolutionary radiation of mammals and birds that define today’s fauna.
Legacy and Connection to Aboriginal Country
For First Peoples of Victoria, the landscapes shaped during the Miocene — mountains, volcanic plains, and river systems — became the foundation of Country. These ancient geological features are reflected in Dreaming stories that speak of fire, water, and creation (Neale, 2017; Rose, 1996).
The Lava Plains of the Western District, for instance, are connected to stories of Budj Bim, the Creator, whose transformation of land and water mirrors the volcanic energy of the Miocene. Such parallels show how Indigenous stories preserve deep geological memory — knowledge of Earth’s transformation encoded in oral traditions long before Western science confirmed it.
Conclusion
The Miocene Era was a turning point in Earth’s history — a time when continents shifted, climates cooled, and life adapted to a changing world. In Victoria and across Australia, it laid the geological and ecological foundations for the landscapes that Aboriginal peoples would later inhabit, shape, and understand through story.
By studying the Miocene, we see how ancient forces — volcanic fire, water, wind, and time — converged to create the Country we live upon today.
References
Begun, D. R. (2004). The Earliest Hominins: Morphology and Ecology. Annual Review of Anthropology, 33, 345–368.
Christophel, D. C., & Greenwood, D. R. (1989). “Changes in vegetation and climate through the Tertiary of southeastern Australia.” Review of Palaeobotany and Palynology, 58, 99–129.
Joyce, E. B. (2010). The Western Victorian Volcanic Plains: A Field Guide to the Newer Volcanics Province. Geological Society of Australia.
McGowran, B., Li, Q., Cann, J., & Padley, D. (2004). The Cenozoic of the Australian Southern Margin: Evolution of a Rifted Continent. Journal of Australian Earth Sciences, 51, 125–145.
Neale, M. (2017). Songlines: The Power and Promise. Canberra: National Museum of Australia.
Rose, D. B. (1996). Nourishing Terrains: Australian Aboriginal Views of Landscape and Wilderness. Canberra: Australian Heritage Commission.
Scotese, C. R. (2015). The Paleomap Project: Paleogeographic Maps of the Miocene Epoch. University of Texas.
Zachos, J., Pagani, M., Sloan, L., Thomas, E., & Billups, K. (2001). “Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present.” Science, 292(5517), 686–693.
Written, Researched and Directed by James Vegter 16/09/2025
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