single page item on stratigraphy issues relevant to Australian geologists. This column discusses international discussions on the global stratotype section and point (GSSP) concept, new developments in stratigrphic classification and upcoming opportunities to showcase Australian examples in 2012. Journal ISSN 0312 4711

GeoSciML is the international standard for transfer of digital geological maps and relational database data. GeoSciML was developed over the past decade by the IUGS Commission for the Management and Application of Geoscience Information (CGI), and was adopted as an Open Geospatial Consortium (OGC) standard in June 2016. Ratification as an official OGC standard marked a coming of age for GeoSciML - it now meets the highest standards for documentation and current best practice for interoperable data transfer. GeoSciML is the preferred standard for geoscience data sharing initiatives worldwide, such as OneGeology, the European INSPIRE directive, the Australian Geoscience Portal, and the US Geoscience Information Network (USGIN). GeoSciML is also used by OGC's GroundwaterML data standard [1] and CGI's EarthResourceML standard [2]. Development of GeoSciML version 4 learnt considerably from user experiences with version 3.2, which was released in 2013 [3]. Although the GeoSciML v3 data model was conceptually sound, its XML schema implementation was considered overly complex for the general user. Version 4 developments focussed strongly on designing simpler XML schemas that allow data providers and users to interact with data at various levels of complexity. As a result, GeoSciML v4 provides three levels of user experience - 1. simple map portrayal, 2. GeoSciML-Basic for common age and lithology data for geological features, and 3. GeoSciML-Extended, which extends GeoSciML-Basic to deliver more detailed and complex relational data. Similar to GeoSciML v3, additional GeoSciML v4 schemas also extend the ISO Observations & Measurements standard to cover geological boreholes, sampling, and analytical measurements. The separate levels of GeoSciML also make it easier for software vendors to develop capabilities to consume relatively simple GeoSciML data without having to deal with the full range of complex GeoSciML schemas. Previously mandatory elements of GeoSciML, that were found to be overly taxing on users in version 3, are now optional in version 4. GeoSciML v4 comes with Schematron validation scripts which can be used by user communities to create profiles of GeoSciML to suit their particular community needs. For example, the European INSPIRE community has developed Schematrons for web service validation which require its users to populate otherwise-optional GeoSciML-Basic elements, and to use particular community vocabularies for geoscience terminology. Online assistance for data providers to use GeoSciML is now better than ever, with user communities such as OneGeology, INSPIRE, and USGIN providing user guides explaining how to create simple and complex GeoSciML web services. CGI also provides a range of standard vocabularies that can be used to populate GeoSciML data services. Full documentation and user guides are at www.geosciml.org.

As interpretations of sequence stratigraphy are published in increasing numbers in the petroleum exploration literature, the potential for confusion also increases because there are no rules for the classification or naming of the identified sequences. At present it is difficult to apply databases and geographic information systems to sequence stratigraphy, particularly when organisations with different outlooks and approaches attempt to collaborate and merge their databases. Despite sequence stratigraphic concepts having been in the literature for over two decades, no scheme for standardisation has achieved consensus in the geoscientific community, either within Australia or internationally. Three areas in particular need to be agreed on: (1) how sequence units should be defined; (2) the hierarchy of those units, and on what basis; and (3) a standard scheme for naming units. The two basic ways of subdividing a succession into sequence units, the Vail-Exxon and Galloway methods, both rely on the enclosing boundaries being defined first. Various hierarchies of units have been proposed, in which there is often a clear desire to link the scale of sequence units to phases of geological evolution or stratal boundaries of different orders. In addition, most workers use informal names, but formal names are becoming more common. Consequently, it is essential that workable national guidelines be developed to ensure that communication and computer compatibility are not impeded.

Legacy product - no abstract available

In this age of state-of-the-art devices producing analytical results with little input from analytical specialists, how do we know that the results produced are correct? When reporting the result of a measurement of a physical quantity, it is obligatory that some quantitative indication of the quality of the result be given so that those who use it can assess its reliability. Without such an indication, measurement results cannot be compared, either among themselves or with reference values given in a specification or standard. It is therefore necessary that there be a readily implemented, easily understood, and generally accepted procedure for characterising the quality of a result of a measurement, that is, for evaluating and expressing its 'uncertainty'. The concept of 'uncertainty' as quantifiable attribute is relatively new in the history of measurement, although error and error analysis have long been part of the practice of measurement science or 'metrology'. It is now widely recognised that, when all of the known or suspected components of error have been evaluated and the appropriate corrections have been applied, there still remains an uncertainty about the correctness of the stated result, that is, a doubt about how well the result of the measurement represents the value of the quantity being measured. This presentation will discuss the latest practices for the production of 'reliable' geochemical data that are associated with small measurement uncertainties, and will provide an overview of current understanding of metrological traceability and the proper use of reference materials. Correct use of reference materials will be discussed, as well as the role of measurement uncertainty and how it is affected by such issues as sample preparation, sample heterogeneity and data acquisition.

single page item on Australian stratigraphy issues. This column discusses ongoing co-operation between the State and Territory Surveys; highlights of a trip to the Northern Territory and changes to GA web pages Journal ISSN 0312 4711

No abstract available

No abstract available

In establishing lithostratigraphic units, Australian geologists have been encouraged to follow the International Stratigraphic Guide since 1978. This Guide gives limited, and sometimes conflicting, advice when you try to apply it to the naming of igneous units in particular. The Guide strongly discourages the use of form terms like dyke, pluton or batholith, and adjectives used as nouns, such as volcanics, intrusives and extrusives. It deems the use of 'suite' to be inadvisable, having quite different meanings in different countries. The use of qualifiers such as plutonic, igneous, intrusive, extrusive should be minimised, except for clarifying the nature of a complex. Australia has chosen to make some exceptions to the Guide. We do use suites and supersuites, but only for grouping igneous units, unlike the lithodemic units of the North American Code. We also use volcanics, and volcanic groups, generally for mixed, or bimodal volcanics. We have resisted using intrusives, preferring 'igneous complex' instead. We have also resisted 'dyke swarm' in favour of simple lithological names such as Alcurra Dolerite, but existing, long-standing names such as Widgiemooltha Dyke Suite, make it hard to explain current guidelines to some geologists. Australia's interpretation of the Guide means that 'complex' is used in various ways, at various ranks, and for a very wide variety of sedimentary, metamorphic and igneous units. We are exploring the need to broaden the naming options for igneous units.

Quarterly column on issues in Australian stratigraphy