River elevation, Kangaroo Point House, Kangaroo Point, Brisbane

As seen from jetty, looking back towards house and crow's nest.

Geochronology of weathering and landscape evolution, Dugald River valley, NW Queensland, Australia

40Ar/39Ar laser incremental heating analyses of individual grains of supergene jarosite, alunite, and cryptomelane from weathering profiles in the Dugald River area, Queensland, Australia, show a strong positive correlation between a sample’s age and its elevation. We analyzed 125 grains extracted from 35 hand specimens collected from weathering profiles at 11 sites located at 3 distinct elevations. The highest elevation profile hosts the oldest supergene minerals, whereas progressively younger samples occur at lower positions in the landscape. The highest elevation sampling sites (three sites), located on top of an elongated mesa (255 to 275 m elevation), yield ages in the 16 to 12 Ma range. Samples from an intermediate elevation site (225 to 230 m elevation) yield ages in the 6 to 4 Ma range. Samples collected at the lowest elevation sites (200 to 220 m elevation) yield ages in the 2.2 to 0.8 Ma interval. Grains of supergene alunite, jarosite, and cryptomelane analyzed from individual single hand specimens yield reproducible results, confirming the suitability of these minerals to 40Ar/39Ar geochronology. Multiple samples collected from the same site also yield reproducible results, indicating that the ages measured are true precipitation ages for the samples analyzed. Different sites, up to 3 km apart, sampled from weathering profiles at the same elevation again yield reproducible results. The consistency of results confirms that 40Ar/39Ar geochronology of supergene jarosite, alunite, and cryptomelane yields ages of formation of weathering profiles, providing a reliable numerical basis for differentiating and correlating these profiles. The age versus elevation relationship obtained suggest that the stepped landscapes in the Dugald River area record a progressive downward migration of a relatively flat weathering front. The steps in the landscape result from differential erosion of previously weathered bedrock displaying different susceptibility to weathering and contrasting resistance to erosion. Combined, the age versus elevation relationships measured yield a weathering rate of 3.8 m. Myr−1 (for the past 15 Ma) if a descending subhorizontal weathering front is assumed. The results also permit the calculation of the erosion rate of the more easily weathered and eroded lithologies, assuming an initially flat landscape as proposed in models of episodic landscape development. The average erosion rate for the past 15 Ma is 3.3 m. Myr−1, consistent with erosion rates obtained by cosmogenic isotope studies in the region.

Wall detail, Powell House, Noosa River, Sunshine Coast

External wall and alcove.

Internal hallway, Powell House, Noosa River, Sunshine Coast

View down hall to living room.

Dining and living room areas, Powell House, Noosa River, Sunshine Coast

View through dining and living room areas to external deck.

Dining and kitchen areas, Powell House, Noosa River, Sunshine Coast

View from living room to kitchen.

Powell House, Noosa River, Sunshine Coast

Timber deck with sliding timber shutters off the master bedroom

Timber-framed windows, Powell House, Noosa River, Sunshine Coast

Folding timber windows and roof over.

Powell House, Noosa River, Sunshine Coast

As seen from neighbouring property.

Union for Civil Liberties Demonstration 1967 Brisbane Australia

People listening to speakers during the Union for Civil Liberties Demonstration September 1967 in Brisbane. The demonstration was called by the Trades and Labour Council of Queensland to protest against police treatment of university students and staff in Roma Street, Brisbane during a protest march. The march, from the University of Queensland to the city, had been held a few days earlier.

Combined Railways Union float during Mayday procession 1965 Brisbane Australia

Combined Railways Union float during Mayday procession in 1965, Brisbane, Australia. Banners read Stop menacing hand of Vietnam War and 50,000 people used Beenleigh Southport line in 1963.

Members of the Union of Australian Women with banner during Hiroshima Day 1964, Brisbane

Members of the Union of Australian Women with banner during Hiroshima Day 1964, Brisbane, Australia. The Union of Australian Women is a national organisation that was formed in 1950. Its aim is to work for the status and wellbeing of women across the world. It has been involved in a wide variety of campaigns that concern women. The Union of Australian Women networks with other women's community and union groups on such issues.