1.1 About this site

1.2 Committee on the Stratigraphy of Svalbard: Organisation and purpose

1.3 How to use this site – important user information

• All recommended stratigraphic units are contained in the lexicon parts of the main chapters. These units have ID numbers with prefixes indicating the related era (CP for Late Palaeozoic or Carboniferous/Permian, M for Mesozoic, T for Cenozoic, Q for Quaternary). The ID numbers are used throughout the site and can be used to quickly find and identify a respective unit on tables, lists, log diagrams, type localities, etc.
• Previous names that are not recommended for future use by SKS are written in quotation marks throughout the site. These have short explanations and are listed at the end of each chapter.

• All type sections in this site are redrawn from the originals according to a technical standard established for this purpose at Norsk Polarinstitutt.
• A fold-out legend for all type sections is contained at the inside of the back cover.
• The extremely varying standards, quality and scientific foci of the original sections made it impossible to redraw them according to a scientifically uniform standard. This means that differentiation made in some sections (e.g. sandstone, silty sandstone, siltstone, sandy shale, shale) may not be made in others (e.g. sandstone, siltstone, shale). In most cases, the original quality of information is maintained, although generalisation was undertaken where the purpose of technical standardisation required this.
• As a result of this, for instance, some original sections show a very rough grain size classification, different ways of particle classification (e.g. for carbonate rocks), or none at all which would satisfy the presently accepted standard grain size scale. These sections are adapted to the standard scale, with the note "grain size approximate".
• Almost all redrawn sections have been checked and accepted by the authors of the originals or by a research partner or supervisor. For a few older sections, this was, of course, not possible.
• Where newer and more informative logs of a previously defined type section existed, these new sections are used here. The reference to the original definition is only shown in the text.
• Different kinds of type localities and sections used in this site:
• Stratotype: The main type locality and section which presently define the unit. Due to the often poor documentation of other previously defined type localities, the term neostratotype is not applied, but previously defined stratotypes are mentioned in the text.
• Hypostratotype: The second or third type locality of a unit that documents major regional variations. Hypostratotypes for some units in Svalbard are defined herein for the first time.
• Boundary stratotype and Unit stratotype: If a unit does not have a documented locality where both its base and its main body are sufficiently represented, type localities for the lower boundary and the main unit body are defined separately. The use of boundary and unit stratotypes is here introduced to Svalbard stratigraphy.
• The name-giving localities of stratigraphic units in Svalbard rarely coincide with their type localities. The reason for this is that unit names mostly have not been changed since their first appearance or definition in the geological literature, when type localities were not sufficiently documented. Later, better type localities were often found and documented in different places. Another reason may be the lack of geographical names in the area of the type locality, or the use of the same type locality for several units.
• Availability of cores from type wells: For most Mesozoic type wells, apply to the Norwegian Petroleum Directorate (NPD). For cores from wells containing the letter U in the well number, apply to SINTEF Petroleum Research. For cores from Cenozoic type wells, apply to Kings Bay A/S in Ny-Ålesund, Svalbard.

• During the committee's work on the lithostratigraphic nomenclature, correlations with the stratigraphy of the western Barents Sea Shelf were considered important. Hydrocarbon prospecting in the western Barents Sea has been going on since 1980, and with the expected future developments there, the amount of stratigraphic names will increase. Svalbard is often used as a reference and training area by offshore geologists working in the Barents Sea. It is the committee's opinion that the lithostratigraphic nomenclature systems should clearly show the relationship between the onshore and offshore development and that the framework of stratigraphic groups should reflect this relationship.
• The Late Palaeozoic stratigraphic nomenclature of the offshore areas is presently being worked on by another committee in close co-operation with NSK. Its work is not yet concluded, but there is a general consensus that the framework at group level will be applied from Svalbard, while an additional group is defined in the western Barents Sea, with only one formation represented onshore on the island of Bjørnøya. Available data points on the Upper Palaeozoic of the Barents Sea Shelf are still sparse.
• The nomenclature of the Mesozoic stratigraphy in the western Barents Sea has preliminarily been established in connection with the present work. Abundant data are available, although published data are mainly restricted to the Hammerfest Basin. The overall group framework proposed here will probably be applicable for a long time ahead, while adjustments or additions at lower levels are expected. Work on the offshore Mesozoic nomenclature has made significant progress and Mesozoic offshore formations are included in the present volume.
• The stratigraphy of the Cenozoic offshore basins is not yet well enough known. Cenozoic offshore basins probably developed separately from those exposed onshore.

• Place names in Svalbard have changed significantly throughout history. One reason is the international use of Svalbard through the last centuries. Norway did not start to execute her sovereignty earlier than 1925 (according to the Svalbard Treaty of 1920), when names from other languages gradually started to be translated into Norwegian. Even later, Norway started to pursue the policy of naming – and renaming – places according to spelling in the less wide-spread of the two Norwegian languages, Nynorsk. Many modern, revised spellings did not occur on maps or publications previous to the 1990s. For these reasons, many place-name segments of stratigraphic units do not coincide with the spelling of the respective place names on modern maps, which is disadvantageous.
• SKS has adopted the new spellings for those place names where changes were minor, and where the original name is easily recognised (e.g.: Petrelskardet Formation – Petrellskaret Formation).
• SKS has changed incomplete place names into complete ones in order to avoid formation names with a first segment reflecting, for instance, a person rather than a mountain (e.g.: Vegard Formation – Vegardfjella Formation).
• SKS has not adopted translations of names from, for instance, original English place names (ex.: Wood Bay – Woodfjorden, for a Devonian formation), or other major changes where the original place name would then not be easily recognised.

• This lexicon is attempting to standardise descriptive data from a huge variety of original sources and authors. The various geological units have been investigated and described for different purposes and with a varying quality in the geological literature. It was therefore not always possible, on the basis of existing data, to achieve a consistent way of description. So, for instance, while some units may lack a reference to an interpretation of the depositional environment, others may lack sufficient data on lateral facies variations, etc.
• To avoid much repetition, some features may be described for a superior rank unit (e.g. formation), without being repeated in the description of the inferior rank units (members), or vice versa, depending on what appeared to be most appropriate. The user of the lexicon is therefore asked always to check superior and inferior rank units in order to find the requested information.
• A good definition of its lower boundary is an important property of any geological unit. The great variety of authors of different nations defining these units in Svalbard may result in an inconsistent quality of lower boundary definitions. In many cases, geological units were defined without a proper definition of their lower boundary. These units may still have survived history and be accepted by present geologists as "good" units, simply because they designate characteristic rock successions. Many lower boundary definitions, a demand of modern lithostratigraphy, have therefore been added by the authors of this lexicon as precisely as possible from the existing data. For a number of units, especially for those with interfingering contacts or transitional boundary features, these definitions may appear rather arbitrary.

• Place names in Svalbard which have been used for stratigraphic unit names, have either a descriptive meaning, or are from persons, vessels, etc. Descriptive meanings are translated in the lexicon part of the site, because these names may have geological implications.
• For other place names, and for more information about the names, the reader is referred to 'Place names in Svalbard', Norges Svalbard- og Ishavsundersøkelser (1942) and Orvin (1958), both reprinted by Norsk Polarinstitutt (1991).

1.4 Outline of the geological history of Svalbard