South Australian geology and the State Heritage Register: an example of geoconservation of the Naracoorte Caves complex and karst environment

South Australia’s State Heritage Register contains 2294 listed places, the majority of which are from the ‘Built’ environment, ranging from settlers’ huts, community buildings, historical industrial sites to magnificent stone mansions. Only 96 places are linked to the ‘Natural’ environment. The Register listings protect heritage places from alteration, damage or removal without formal prior consultation, compulsory under the South Australian Development Act. ‘Natural’ environments are landscape-based and oriented towards Geological, Archaeological, Palaeontological and Speleological heritage (‘GAPS heritage’). A process to provide a greater balance between ‘Natural’ and ‘Built’ listings has initiated a series of State Heritage ‘Natural’ environment assessments, mostly of single sites. Two individual caves in the Naracoorte Caves National Park are already entered in the State Heritage Register as single sites. However, an innovative broader multiple-site nomination has focused on the many different but significant GAPS features contained within the 25 caves of the Naracoorte Caves National Park, providing a further level of protection for the land and the caves’ exteriors and interiors. The example of the Naracoorte Caves draws attention to the number of important land and coastal karst (limestone) features across South Australia that were generated by steady geological uplift of three large sections of Oligocene–Miocene limestone—the Nullarbor Plain, the Murray Basin and the Gambier Karstfield (which includes Naracoorte and Mount Gambier), resulting in specific karst forms worthy of a broader coordinating management approach across South Australian karst parks.     

Sedimentary and drainage evolution of the Condamine Valley Transition Zone (eastern Australia)

The basal succession of the Condamine Valley, which overlays the boundary between the Surat and Clarence-Moreton basins (eastern Australia), contains a clay-rich horizon ‘the Transition Zone’ that marks a pronounced unconformity between the Jurassic Walloon Coal Measures and the Quaternary Condamine Alluvium. This paper provides insights into the tectonic and drainage evolution of the Condamine Valley through integrated analysis of U–Pb ages of detrital zircon from three samples (494 concordant analyses), stable oxygen isotope analysis on eight authigenic clay samples, X-ray fluorescence of primary and trace elements, and hyperspectral mineral analysis from two drill cores (Lone Pine 17 and Daandine 164). The Transition Zone is interpreted to consist of both weathered Jurassic sediments and Cenozoic clay deposits. Two sequential cycles of erosion, deposition and pedogenesis, related to geomorphological and climatic conditions are recognised. Distinctive oxygen isotope signatures of the two weathering fronts demonstrated an initial Early Cretaceous phase (δ¹⁸O?=?11.9–15.7‰ VSMOW) associated with laterisation and possible uplift, followed by Paleogene (δ¹⁸O?=?16.4–17.3‰ VSMOW) silcretisation of reworked Jurassic sediments. Detrital zircon geochronology yielded Jurassic maximum constraints for the age of deposition of three samples that are indistinguishable within error, the oldest of which (163?±?8?Ma from the lateritic profile) corresponds to the age of the underlying Walloon Coal Measures. The two overlaying samples from a silcrete profile and granular alluvium yielded overlapping yet younger ages of 150?±?6?Ma and 156?±?9?Ma, respectively. Vitrinite reflectance used as a proxy for the thermal condition of the coal strata enabled an estimated 2–3?km of burial and subsequent (likely Early Cretaceous) uplift. Geochemical insights from the Condamine Valley correspond to broad-scale climatic and tectonic conditions, suggesting that ‘transition zone equivalents’ and corresponding groundwater dynamics may occur in similar sedimentary settings throughout eastern Australia.     

Saving and conserving the caves: reflections on 37 years of listings,disputes, submissions and court cases

In order of impact, the main anthropogenic threats to caves in eastern Australia are and have been for the European history of Australia: mining, inundation, vandalism, wear and tear, lampenflora, lint and dust, scientists and poorly informed decisions. Destruction of caves by natural processes is not a focus of this paper as it occurs over a geological time scale and there are few historical accounts of natural catastrophic cave failure. Saving and protecting caves are difficult due to the reliance and insistence on conservation by secrecy used by cavers and the organisations that represent them. Other issues that inhibit cave conservation are: limited public exposure, perceptions of land managers and farmers about caves, a shortage of research-based information on caves and difficulties with establishing the significance of a cave. Cave monitoring and the education of managers and cave guides are known to enhance the conservation of show caves. Actions that would help to save and conserve caves throughout Australia include: changes to planning legislation, establishment of a cave conservation organisation, introduction of specific cave protection legislation and the establishment of a Research Centre for Caves, Karst and Geoheritage.     

澳大利亚冷空气活动对西北太平洋热带气旋生成的影响

利用1980—2012年NCEP/NCAR再分析资料及中国气象局的最佳台风路径资料,研究澳大利亚冷空气活动对西北太平洋热带气旋生成的影响。研究发现,北半球夏季925 h Pa经向风超过6 m/s的频数在澳大利亚东北部海域最高,达40 d/a。为此,确定澳大利亚冷空气侵入南北半球低纬的关键区为澳大利亚东北部所罗门海地区,并用该区域经向风风速定义了一个澳大利亚冷空气活动强度指数。该指数与越赤道气流及赤道西风都有很好的相关关系,还与同期的SOI(Southern Oscillation Index,南方涛动指数)显著相关。当SOI偏低(高)时,关键区经向风风速偏强(弱)。合成分析和相关分析结果表明,澳大利亚冷空气活动强、弱年西北太平洋热带气旋生成的位置的变化与季风槽的变化一致,西北太平洋热带气旋生成总数则无显著差异。澳大利亚冷空气活动强年季风槽偏强偏东,热带气旋生成位置偏东偏南;而弱年季风槽偏弱偏西,热带气旋生成位置偏西偏北。低层涡度场、水汽输送、风垂直切变以及低纬地区对流活动的分布表明,澳大利亚冷空气活动强年有利于热带气旋生成位置偏东、偏南;弱年偏西、偏北。     

Management Challenges for Aboriginal Cultural Heritage in Peri-urban Queensland

It is often assumed that places of cultural significance to Aboriginal and Torres Strait Islander peoples are protected under cultural heritage legislation such as the Aboriginal Cultural Heritage Act 2003 in Queensland. Such Acts are improvements on previous policies, which all but neglected Aboriginal cultural heritage. Nevertheless, the aims of policies developed at wider geographic scales, such as States within the Australian system, continue to be disconnected from the experiences of some local Traditional Owners. In this paper, we examine conflicts between non-local policy and on-ground management decisions for Aboriginal cultural heritage in peri-urban Queensland. We focus on the challenges of local Traditional Owners in peri-urban landscapes, basing our discussion on recent experiences conducting research on Indigenous land management in southeast Queensland. We examine three case studies: one in which colonial heritage values were prioritised over existing Aboriginal cultural heritage values, a second where local government failed to support a private landholder’s attempt to identify and protect a cultural heritage site, and a third where a cultural heritage site was protected but in a way that restricts the continuation of cultural practices. Developing more productive and equitable relationships between Traditional Owners and non-Indigenous decision makers, with regards to Aboriginal cultural heritage, requires new locally developed processes for engagement and we suggest how this could be achieved.     

两广地区夏季降水异常与澳大利亚东侧海温异常的联系及可能机制

广东省和广西壮族自治区(两广地区)夏季降水时空分布很不均匀,存在显著的年际变化。利用站点观测降水资料、海洋及大气再分析资料,研究了近40 a两广地区夏季降水年际异常与澳大利亚东侧海温异常的联系及机理。在年际时间尺度上,两广夏季降水异常与澳大利亚东侧的海温异常存在显著的负相关关系。当澳大利亚东侧海温异常偏高时,一方面,部分水汽由热带中太平洋向澳大利亚东侧海区辐合,部分沿西太平洋副热带高压边缘向东亚地区输送,两广地区为水汽辐散区域,另一方面,澳大利亚东侧海区的对流活动增强,该地区上空的上升运动异常增强,通过"大气桥"遥相关使得海洋性大陆地区的异常上升运动增强,从而加强了东亚地区的局地Hadley环流,使得两广地区下沉运动增强,二者共同作用致使两广地区夏季干旱少雨;反之亦然。     

“Clusters” or “communities”? Analysing the spatial agglomeration of video game companies in Australia

In this paper, I question whether agglomerations of video game companies in Australia function as clusters (spatially bound) or rather as communities (not spatially bound). The two case studies included in the analysis are the main agglomerations of video companies in Australia—Brisbane and Melbourne. The data have been collected through 21 semi-structured interviews performed between 2012 and 2014. The main findings are as follows: (1) the primary reason that video game companies come together is to share tacit knowledge and skilled labour; (2) these agglomerations do not have the attributes of “creative clusters”; and (3) new technologies enable experienced game developers to operate at the geographic periphery of the main agglomeration of developers. Therefore, to paint a more accurate picture of why some video game companies are successful—beyond simply positive externalities associated with co-localization—I propose the term “networked communities.” This recognizes that social networks at varying scales (local, national, international) are being developed by video game firms in order to thrive and reach a global audience.     

Exploitation or 'Wise Use' of the Coongie Lakes,South Australia: Issues arising from a petroleum exploration proposal

The exploitation of natural resources within areas that are valued for their environmental qualities raises competing emotions. This paper considers a proposal to undertake petroleum exploration in an area of recognised environmental value, namely, the Coongie Lakes of far north-east South Australia. In development cases such as this, the level of inquiry needs to address environmental, social, cultural and economic issues from a range of interest groups; therefore, the process of assessment is a crucial factor in minimising conflict and meeting the wishes of the stakeholders. In the example of Coongie Lakes, the chosen method failed. This paper discusses the perspectives of the major stakeholders, the process of assessment undertaken, and the criticisms directed at this process. The apparent inadequacies of the assessment process undertaken are then highlighted, and an alternative assessment procedure suggested.     

Deep crustal structure and rheology of the Gascoyne volcanic margin,western Australia

Interpretation of deep seismic reflection data across the Gascoyne Margin reveals six distinct seismic facies units related to the tectono-magmatic breakup history. On the outer Exmouth Plateau four large scale units are identified: (1) an extensively block-faulted upper crust; (2) a middle-crustal unit of discontinuous, undulatory reflectors; (3) a reflection-free deep crustal unit; and (4) a lower-crustal band of low-frequency, high-amplitude reflectors. Two additional units are found near the continent-ocean boundary (COB); (5) seaward-dipping reflectors (SDR); and (6) landward-dipping reflectors in the lower crust below the SDR. The lower-crustal high-reflectivity band, located near the top of a high-velocity unit (V_p > 7 kms^–1), is interpreted as magmatic underplating. There is a spatial correlation between the underplated area and the presence of extensive upper-crustal block-faulting and intrusive rocks in the shallow crust. The undulatory middle-crustal reflector unit is also only identified in the outer plateau area, and is interpreted as a zone in which the upper-crustal faults terminate. The inner parts of the margin consist of a deep basin showing little upper-crustal faulting and no evidence of middle crustal deformation or underplating. Theoretical modeling of the effect of rifting and magmatic underplating on crustal strength profiles suggests that the brittle-ductile transition may migrate at least 5 km upwards during several million years after the underplating event. Based on the seismic interpretation and crustal strength modeling we propose that the seismic structure of the outer Exmouth Plateau is severely modified by a transient change in the crustal rheological structure associated with magmatic underplating.     

Organochlorine Pesticide Residues in Soils and Sediments of the Herbert and Burdekin River Regions, North Queensland – Implications for Contamination of the Great Barrier Reef

Organochlorine pesticides were widely used in the Australian sugarcane industry from the early 1950s until the late 1980s. Erosion of sugarcane soils and subsequent transport of sediment bound contaminants in river run-off to the Great Barrier Reef lagoon is a growing concern as the cane industry continues to expand. Organochlorine pesticide residues can be used as tracers to examine the worst-case scenario of the spatial extent to which currently used, though less persistent, organic agricultural pesticides might extend. The coastal alluvial flood-plains of the Herbert and Burdekin Rivers in North Queensland have sugarcane growing as the major coastal land-use. Sediment cores and surface sediment samples were collected from near-shore coastal regions of the Herbert and Burdekin Rivers. In addition, soil samples from cane-fields in the two catchments were collected. Analyses of the marine surface sediment samples and three sediment cores revealed the absence of detectable concentrations of organochlorine pesticides (<5 pg/g). However, easily detectable concentrations were found in the sugarcane soil samples (0.01–45 ng/g).