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The Woolshed Creek fossil site near the Royal Military College, Duntroon, Canberra, contains brachiopods Atrypa duntroonensis (early Homerian, early Silurian, ca 430.5 Ma) within a mudstone of the Canberra Formation. Their discovery in 1844 by the Reverend William B. Clarke ("the Father of Australian Geology"), and subsequent comparison with other fossil collections from around the world, contributed significantly to the nineteenth century debate about the oldest rocks in Australia. The fossil site is now on the ACT Government Heritage List and recent site improvements make it readily accessible via a pathway from the sports grounds of the Royal Military College. [ABSTRACT FROM AUTHOR]

This paper investigates and quantifies the near-field and far-field contamination effects from Groupe de Recherche en Geodesie Spatiale GRACE products to assess whether or not they influence the accuracy with which hydrological signals in the Murray-Darling Basin, southeast Australia can be estimated. Far-field contamination was assessed by simulating some of the world's largest geophysical processes which generate major gravitational signals (e.g. melting of the Greenland icesheet, hydrology in the Amazon Basin) and measuring the proportion of the simulated signal detected in the Murray-Darling Basin. Near-field contamination from the Australian continent (excluding the Murray-Darling Basin) was also assessed. The sum of the near-field and far-field effects revealed a maximum of ∼10 mm (equivalent water height) of spurious signal within the Murray-Darling Basin. This equates to only one quarter of the formal uncertainty of the basin-scale estimates of changes in total water storage. Thus, GRACE products can be used to monitor broad-scale hydrological trends and variability in the Murray-Darling Basin without the need to account for contamination from external geophysical sources. [ABSTRACT FROM AUTHOR]

Isotope geology began in the Department of Geophysics, the Australian National University, Canberra, in the late 1950s. A K-Ar dating laboratory was set up in 1960, with development of Rb-Sr dating facilities taking place soon after. These laid the foundations for extensive programs of isotopic dating with emphasis on providing quantitative age information related to the geological evolution of the Australian continent. Demonstration of progressive younging of granite emplacement to the northeast in the Tasman Fold Belt of eastern Australia was a notable initial achievement. Early successes on broader questions included the demonstration of the ability to measure K-Ar ages on young volcanic rocks, leading on to a significant role in the establishment of the geomagnetic polarity time-scale. In the early 1970s, dating of returned lunar samples by the Rb-Sr method was another most notable success. The development of the SHRIMP ion microprobe, commencing in the mid-1970s, resulted in U-Pb dating of zircon (and other minerals) becoming possible on very small areas of single crystals, revolutionising the approach to dating, with wide application not only to rocks in Australia, but indeed worldwide. Isotope geochemical study of the Earth's mantle and crust was also an important activity, especially in the 1980s. Subsequently, emphasis has been redirected toward studies of the Quaternary, including U-series isotopic dating as well as high-resolution isotopic and element ratio measurements, especially on corals, to track climate change. Many other developments in isotopic dating and isotope geochemistry have taken place over the last 45 years with installation and, in some cases, development of appropriate instrumentation, facilitating the updating of capabilities and expanding the range of techniques, continuing to the present time. [ABSTRACT FROM AUTHOR]