A narrow lamprophyre dyke, dated at 85 Ma, intrudes Early Carboniferous sediments at Mount Woolooma in northeast New South Wales. The lamprophyre contains megacrysts of titanbiotite (Mg18-21, 7-8% TiO2) and rare Ti-Al salite (Mg67-72 , 6-9% Al2O3), ilmenite (5% MgO), titanphlogopite (Mg61 , 9% TiO2) and apatite. The host rock consists of lamprophyric-textured titanphlogopite (Mg62-70, 7-8% TiO2), diopside-salite, olivine, kaersutite, and Ti-magnetite in a K-feldspar-rich base. The rock resembles a minette (mica-lamprophyre), but its bulk composition is richer in SiO2 and Al2O3 (53-54% SiO2 anhydrous, ~ 16% AI2O3), and poorer in MgO (3%), Ni and Cr (30 ppm) than many minettes elsewhere. The Mount Woolooma minette forms part of a diverse assemblage of alkaline igneous rocks from the Scone-Gloucester area. These include alkali olivine basalt, teschenite, biotite alnoite, kimberlite, and leucite monchiquite, many of which carry mantle xenoliths/xenocrysts and/or megacrysts.

Pollen and spore assemblages have been recovered from coaly lenses and marginal facies of Tertiary lacustrine sediments at Lake Bunyan, north of Cooma, southern New South Wales. Remains of lake sediments in the area are extensive , and a variety of facies has been recognised. Clays are dominant, but volcanogenic conglomerates, sands, silts , coals, diatomites , and a marginal quartzose facies also occur. Palynological assemblages have been recovered from coaly lenses and from the marginal facies. The pollen and spore suite is poorly diversified. Pollen of Nothofagus dominates, and that of podocarpaceous conifers is well represented. Myrtaceous pollen is common in a few samples only, proteaceous pollen is very rare , and there is occasional local dominance by aquatic taxa. Dating is made difficult by a lack of known stratigraphic marker species. In general, the assemblage resembles microfloras of the Proteacidites tuberculatus Zone, which spans the early Oligocene through early Miocene interval in the Gippsland Basin. The presence of Haloragacidites haloragoides, however, is more in accord with the Triporopollenites bellus Zone, of late early to late Miocene age. Detailed comparison with other palynological suites from highland sites dated by association with basalts suggests an age for the Lake Bunyan deposit of 12-21 m.y. , i.e. late early to middle Miocene. In comparison with other Miocene pollen floras from southeastern Australia , the Bunyan assemblage lacks forms indicative of subtropical rainforest, and forms indicative of cool temperate rainforest are poorly diversified. These features, combined with the relative abundance of conifer pollen in the assemblage, may reflect conditions somewhat cooler than other areas of southeastern Australia during the Miocene. An interpretation of pollen spectra from the deposit suggests that a variety of lake edge and bog communities successively surrounded the sites examined.

The Lithgow earthquake of magnitude ML 4.3, which took place on 13 February 1985, was the largest earthquake to have occurred in the Blue Mountains region of New South Wales since the Kurrajong earthquake of 1919. It caused minor damage in Lithgow and Wallerawang and was felt as far away as Parkes and Dubbo, 200 km from the epicentre. The total damage was estimated at approximately $65 000. Macroseismic and instrumental evidence suggests that, for this earthquake, the attenuation to the northeast in and under the Sydney Basin was much greater than the attenuation to the southwest through the Lachlan Fold Belt.

The eastern margin of the Australian continent was the site of convergent plate interaction for much of the Palaeozoic Era. The Tamworth Terrane, a forearc complex resulting from this interaction, occurs in the northeastern corner of New South Wales. This forearc basin, now preserved as a complex erosional and tectonic remnant in the Tamworth belt and Hastings block, originally formed a relatively linear belt before terrane dispersal resulting from Permian orogenesis. Tectonic-subsidence curves derived from thirteen well-exposed sections show that subsidence began abruptly, continued for approximately 50 Ma, and then ceased just as abruptly. Total tectonic subsidence was 4- 6 km at either end of the basin, and 2- 3 km in the intervening areas of the southern Tamworth belt. Depositional patterns were controlled largely by sediment supply and subsidence; the preserved sedimentary rocks form a large-scale upward-shallowing succession. In detail, the effects of eustatic sea level change are also apparent, particularly around the basin margins and in the shallower water associations. The continuous interaction among these three major variables produced a basin that changed in morphology both spatially and temporally.

An earthquake occurred without warning at 10:27 am on 28 December 1989 (local time) causing loss of life in the city of Newcastle, New South Wales, Australia, the first earthquake to cause fatalities in Australia since European settlement. The magnitude is estimated to have been 5.6 on the Richter scale. Earthquakes of this size occur on average about once every eighteen months in Australia. A single aftershock was recorded on a network of ten seismographs installed on 29 December in and around Newcastle; it had a magnitude of 2.1. The focal depth of the mainshock was 11.5±0.5 km and of the aftershock 13.5±0.8 km, which is beneath the Permian sediments of the Sydney Basin. The epicentres of both earthquakes are coincident within the error bounds and are some 15 km from the centre of damage in the City. The damage in Newcastle was made worse by an underlying thin layer of alluvium which magnified the ground motion substantially. A fault-plane solution indicates that the earthquake had a thrust mechanism with nodal planes striking in a NW-SE direction, parallel to the mapped surface faults in the region. Limited strong motion data were recorded, but not close to the epicentre.

Seismic exploration throughout the Eromanga Basin has identified several regionally-extensive seismic reflection horizons. The C horizon, at the boundary of the Wallumbilla and Cadna-owie Formations, is one of the most significant. A difference in the petrophysical properties of these two formations is evident from sonic, density, gamma ray and resistivity well log data, and indicates that the amplitude of the C horizon reflection is related to a sequence of low-density (undercompacted) shales in the basal part of the Wallumbilla Formation. The properties of the shales appear to be a consequence of rapid subsidence (undercompaction) and burial. The empirical relationships between the C horizon reflection amplitude, formation density and reflection coefficient are discussed, and geological implications for petroleum prospectiveness of the Eromanga Basin are outlined.

Radial drainage centred on Brown Mountain suggests that the Monaro basalts are remains of a former shield volcano, here called the Monaro volcano. At the time of the volcanos eruption the Great Escarpment did not exist and relief was probably low about 50 Ma ago. The volcano diverted original north-flowing drainage to the west, via the Snowy River. Rivers near Jindabyne and Adaminaby (indicated by the Kiandra basalts) that originally flowed northwest were reversed by tectonic uplift (possibly 1 km vertical) of the Snowy Mountains post-22 Ma. The reversed rivers were deflected by the Monaro volcano, one to the Murrumbidgee, the other to the Snowy River. Uplift was therefore in two phases: the first, post-50 Ma; the second, post-22 Ma.

Acid drainage from the abandoned base-metals mine at Captains Flat, New South Wales, is the main contributor of zinc to the Molonglo River in low flow conditions. In 1982, zinc was detectable in the river for 50 km downstream of Captains Flat. Rehabilitation works at the mine site have effectively stabilised tailings dumps, and neutralised them as a source of major pollution.