Capel and Faust Basins - New Information from the Offshore Frontier Between Australia, New Zealand and New Caledonia

New geophysical and geological datasets have been acquired in water depths of 1300-2500m from the Capel and Faust basins located some 800 km east of Brisbane (Figure 1). Between December 2006 and January 2007 Geoscience Australia acquired ~6000 km of industry standard 2D seismic data using an 8 km solid streamer. The survey identified numerous depocentres, some up to 150 km in length and 40 km in width with up to 7 km of sediment fill. Initial interpretation has identified a potential pre-rift succession, three syn-rift phases (clastic/volcanic), and two post-rift carbonate packages. Episodes of post-rift igneous activity are also apparent. Possible correlations with the Capricorn, Great South and/or deepwater Taranaki basins are suggested.

In late 2007 the RV Tangaroa completed a marine reconnaissance survey of the Capel and Faust basins. Geophysical datasets acquired on this survey included gravity, magnetics, multibeam sonar, and sub-bottom profiler data. An accompanying seafloor sampling program acquired geological and biological samples from potential seepage sites and representative areas of the sea floor, to search for indications of active petroleum systems and to document marine biodiversity and habitats. These datasets are designed to better define the region's petroleum prospectivity and inform marine and environmental planning decisions.

The multibeam sonar revealed seafloor features that appear to reflect the underlying basin structure, such as fault-related slumps. The gravity and magnetic coverages are expected to significantly improve the delineation of depocentre boundaries. Seafloor sampling and camera footages provided information on the substrate composition and potential fluid escape sites. Current work involves the initial interpretation of these datasets and their integration to define the rift basin architecture and tectonostratigraphic history to better understand the region's petroleum prospectivity.

研究团队已在布里斯班以东约800公里的开普（Capel）盆地与福斯特（Faust）盆地，完成水深1300~2500米区间的地球物理与地质数据集采集工作（见图1）。2006年12月至2007年1月期间，澳大利亚地球科学局（Geoscience Australia）采用8公里刚性拖缆，采集了约6000公里的行业标准二维地震（2D seismic）数据。本次调查共识别出多个沉积中心（depocentre），其中部分沉积中心长可达150公里、宽达40公里，沉积物充填厚度最高达7公里。初步解释工作已识别出一套潜在的裂谷期前（pre-rift）层序、三个裂谷期（syn-rift）演化阶段（对应碎屑岩/火山岩组合）以及两套裂谷期后（post-rift）碳酸盐岩组合，同时还发现了裂谷期后火成活动的踪迹。研究同时提出，该盆地可与摩羯座（Capricorn）盆地、南大（Great South）盆地及深水塔拉纳基（Taranaki）盆地开展对比分析。

2007年末，“坦加罗阿号”（RV Tangaroa）科考船完成了开普与福斯特盆地的海洋普查工作。本次调查采集的地球物理数据集涵盖重力（gravity）、磁力（magnetic）、多波束声呐（multibeam sonar）及浅地层剖面仪（sub-bottom profiler）数据。配套开展的海底采样计划，从潜在油气渗漏点及典型海底区域采集了地质与生物样本，旨在寻找活跃油气系统（petroleum system）的相关迹象，并记录该区域的海洋生物多样性（marine biodiversity）与栖息生境。本系列数据集旨在更精准地刻画该区域的油气勘探潜力，同时为海洋与环境规划决策提供科学支撑。

多波束声呐探测发现了能够反映盆地深部构造的海底特征，例如与断层相关的滑坡体（fault-related slump）。重力与磁力数据有望大幅提升沉积中心边界的圈定精度。海底采样与摄像资料则提供了底质组成及潜在流体逸出点的相关信息。当前研究正围绕这些数据集的初步解释与整合分析展开，旨在明确裂谷盆地构造格架（rift basin architecture）与构造地层演化史（tectonostratigraphic history），从而进一步厘清该区域的油气勘探潜力。