The Proterozoic Mount Isa terrain records the effects of four periods of intraplate tectonism. The
c
. 1870 Ma Barramundi Orogeny was characterized by a massive felsic magmatic event, and global correlations suggest a physical link between Australia and Laurentia at this time. Thereafter, the terrain underwent an extensional history spanning 200 Ma involving repeated episodes of rifting, post-rift subsidence and associated depositional and magmatic phases. This protracted rifting history resulted in a cumulative stratigraphic thickness of up to 25 km above attenuated continental crust. Rifting was interrupted prior to the formation of ocean crust by the compressional Isan Orogeny (1590–1500 Ma). The Isan Orogeny was synchronous with low-pressure high-temperature metamorphism and widespread metasomatism. In the waning stages of shortening, the Mount Isa terrain evolved into a wrench system characterized by an extensive network of strike-slip faults. The current level of exposure in this terrain provides spectacular examples of superimposed rifts, basin inversion, and wrench geometries developed at middle to upper crustal levels.
The Mt Isa Rift Event is a Palaeoproterozoic intracontinental extension event that defines the beginning of sedimentation into the Isa Superbasin in the Western Fold Belt, Mt Isa terrane. In the mildly deformed Fiery Creek Dome region, on the northwest flanks of the Mt Isa Rift, elements of the Mt Isa Rift Event rift architecture are preserved without being intensely overprinted by later deformation. In this region two discrete generations of northwest-dipping normal faults have been identified. Early generation normal faults were active during the deposition of fluvial and immature conglomerate and sandstone of the Bigie Formation. Renewed rifting and the development of late-generation normal faults occurred during deposition of shallow-marine sandstone and siltstone of the lower Gunpowder Creek Formation. Differential uplift between tilt blocks formed an array of spatially and temporally discontinuous synrift unconformities on the crests of uplifted tilt blocks. Applying the domino model yields ~28% crustal extension for the entire Mt Isa Rift Event. Northwest-striking transverse faults facilitated differential displacement along normal faults and formed boundaries to normal fault segments, creating smaller depositional compartments along half-graben axes. Three large domes were formed during laccolith emplacement. These domes produced palaeogeographical highs that divided the region into sub-basins and were a source for the coarse fluvial synrift sequences deposited during the early Mt Isa Rift Event. The basin architecture in the Fiery Creek Dome region is consistent with northwest-southeast-directed extension.
The 4th International Polar Year featured a range of large international research projects and included a focus on Education and Public Outreach (EPO). ANDRILL (the ANtarctic geological DRILLing Project) was a large international (USA, New Zealand, Italy, Germany) multidisciplinary research project investigating the sedimentary record of Cenozoic ice sheet dynamics that brought approximately 160 scientists to McMurdo Station in the 2006 and 2007 field seasons, during which two > 1000 m sediment cores were successfully retrieved from the floor of the Ross Sea. ARISE (ANDRILL Research Immersion for Science Educators), the EPO arm of ANDRILL, deployed an international team of six to eight educators each season to Antarctica and embedded them with science teams. ARISE was unique in the EPO spectrum because it deployed a team of international educators together with an EPO coordinator, offered an on-ice geoscience course for the educators, and supported educator participation at both pre-ice and post-ice meetings. Conservative estimates indicate that at least 314,700 individuals have been reached directly through the wide range of ARISE EPO endeavours.Educator field research immersion is a small subset of educator professional development (PD) opportunities, with little quantitative or qualitative evaluation of polar immersion experiences having been reported. Here, surveys of ARISE educators and scientists are used to evaluate the efficacy of the ARISE program as PD in the context of research on educator PD. Persistent and recurring themes emerging from the surveys are: (1) the positive and reinforcing impact of deployment as a team; (2) the importance of access to scientists across an extended period of time and venues; (3) the importance of ‘doing science’ as a means of learning; and (4) recognition of the senses of excitement, engagement and inspiration displayed by both educators and scientists − about drilling progress, core interpretation, and outreach plans – and the EPO audience. Key components of the program are shown to be (1) deployment of a multi-educator team; and (2) guidance and support of the EPO coordinator at all phases of the ARISE experience.
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