Surface Geology of Australia 1:2.5 million scale dataset 2012 edition

The 1:2.5M scale geology of Australia data documents the distribution and age of major stratigraphic, intrusive and medium to high-grade metamorphic rock units of onshore Australia. This edition contains the same spatial content as the previous edition, but its geological attribute data is more complete than the 2010 edition. The dataset was compiled to use at scales between 1:2.5 million and 1:5 million inclusive. The units distinguished/mapped mainly represent stratigraphic supergroups, regional intrusive associations and regional metamorphic complexes. Groupings of Precambrian units in the time-space diagram are generally separated by major time breaks; Phanerozoic units are grouped according to stratigraphic age i.e. System/Period. The time-space diagram has the added benefit that it provides a summary of units currently included on the themes. The method used to distinguish sedimentary and many volcanic units varies for each geological eon as follows: - Cainozoic units are morphological units which emphasise the relationship of the sedimentary fill to the landscape. - Mesozoic units are regionally extensive to continent-wide time-rock units which emphasise the System of Period(s). - Paleozoic units are stratotectonic units that emphasise either the dominant System or Period(s) or the range of Periods. - Proterozoic units are commonly regional stratotectonic units - separated by major time breaks and split into the Paleoproterozoic, Mesoproterozoic and Neoproterozoic Eras - which are generally unique to each cratonic region. - Archaean units are regional lithological units grouped into broad time divisions.Metamorphic units are lithological units which emphasise the metamorphic facies and timing of the last major metamorphic event.

1:250万比例尺的澳大利亚陆上地质数据集，记录了澳大利亚陆上主要地层、侵入岩以及中高级变质岩单元的分布与形成年代。本版数据与前版拥有相同的空间内容，但地质属性数据较2010版更为完备。本数据集的适用比例尺范围为1:250万至1:500万（含两端）。本次识别/填绘的单元主要包括地层超群、区域侵入岩组合以及区域变质岩杂岩。时空图中的前寒武纪（Precambrian）单元分组通常以重大时间间断为界；显生宙（Phanerozoic）单元则按地层年代（即系/纪）进行分组。该时空图的额外优势在于，可对当前主题下包含的所有单元进行汇总梳理。区分沉积岩与多数火山岩单元的方法因不同地质宙而异，具体如下：
- 新生代（Cainozoic）单元为地貌单元，着重体现沉积充填物与地表景观之间的关联。
- 中生代（Mesozoic）单元为区域延展至大陆范围的时间岩石单元，着重体现其所属的系/纪。
- 古生代（Paleozoic）单元为地层构造单元，着重体现其主导系/纪或纪的分布范围。
- 元古宙（Proterozoic）单元通常为区域地层构造单元，以重大时间间断为界，并进一步划分为古元古代（Paleoproterozoic）、中元古代（Mesoproterozoic）与新元古代（Neoproterozoic），且各单元通常仅对应特定克拉通区域。
- 太古宙（Archaean）单元为区域岩性单元，按宽泛的时间划分进行分组。变质岩单元为岩性单元，着重体现其变质相（metamorphic facies）与最后一次重大变质事件的发生时间。