LIST OF ILLUSTRATIONS
TABLES with unit names and type sections/localities
APPENDIX 1: Biostratigraphic tables
APPENDIX 2: Extract from 'Rules and recommendations for naming geological units in Norway'
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Extract from: 'Rules and recommendations for naming geological units in Norway' by the Norwegian Committee on Stratigraphy (Nystuen, ed., 1989)2 General rules for naming and defining geological units
2.1 Formal and informal units and names: definition
The Code distinguishes between formal and informal geological units. These have formal and informal names, respectively. Formally defined units are given protected status, affording priority to the specific proper or characterizing names used for them. Names of informal units do not have such protection, but can be protected following evaluation by NSK. Protection can be lifted if names are not in practical use. Formal and informal names can be distinguished in various ways in writing and orally.
2.2 Names of formal units
2.2.1 The reason for having formal units
Formal geological units are to be defined with the aim in view that the names given to them will be able to function for a long time retaining a stable, unambiguous geological significance. The name is to be used (a) on official geological maps, (b) in published scientific works and technical reports, and (c) in other reports and documents connected with business, public administration and administrative bodies of a political nature. The practical need for a unit, and a certain level of knowledge about it, will need to be demonstrated before the unit can be formally defined and erected.
2.2.2 Construction of formal names
Names of formal geological units are compound terms, usually made up of two or three parts. In the case of geological units that are looked upon as single, physical entities the first component of the name is the proper name. For geological units of a collective nature (see Section 1.3), such as a period of time, this is a distinguishing collective name. It may be a geographical term or some other sort of name representing the type section, type locality or type area/area of distribution. The second component of two part names may denote (a) the rank of the unit in the classification system (e.g. group, formation, lithodeme, biozone, etc.), (b) the principle lithology of the unit (e.g. sandstone, basalt, conglomerate, etc.), or (c) the rank and/or distinguishing character of the unit (e.g. nappe, fault, basin, plug, syncline, etc.). In three part names, the middle part can be a descriptive name placed between the proper or characterizing name and the part signifying rank or lithology. Such three part names should be used as little as possible. ...
2.2.3 Naming geological units on land
Geological units exposed on land are given a proper or characterizing name. This is a geographical name from the type section, type locality or type area for the unit. The geographical name should preferably be on an official topographical map and is to be written as it is spelt on the map except when this conflicts with rules for spelling compound names. However, the guiding principle when spelling geographical names should be that the long-standing, local pronunciation should form the basis for the spelling, as is the case in the rules for spelling official geographical names. ...
2.2.6 How to write formal names in Norwegian
Formal names are to be written in Norwegian in accordance with the rules for pronouncing and spelling compound Norwegian words. Compound names which can be pronounced as one word are also to be written as one word, using an initial capital letter and without hyphenating the individual components of the name. ...
2.2.7 How to write formal names in English and other foreign languages
In English, formal names must conform to English orthography and the rules given in ISSC (1976). The proper or characterizing name is to be written in full as it is spelt according to official Norwegian orthographical rules and approved forms of names. In contrast to the Norwegian way of writing the name, the Norwegian definite articles –en, -a, -et, -ene are to be retained if they are part of the official name (when the definite article "the" is used in front of the unit name it signifies that the entire unit name is to be understood in a definite form). In two part or three part unit names each part is written as a separate word with an initial capital letter. Rendalsformasjonen is therefore written in English as "the Rendalen Formation" and Sjodekket as "the Sjoa Nappe".
... If the formal name is to be written in other languages the way of writing it should be adapted in a corresponding manner to the national orthographical rules in question. The Norwegian letters æ, ø and å are, however, to be retained when the name is written in English or other languages. Exceptions can be made for typographical reasons. ...
Units which have been named after international waters or other large regional areas, can be spelt according to the rules of Norwegian, English or other desired languages, according to what is most appropriate. An example here is the Barents Sea Group (Barentshavsgruppen).
2.2.9 Changes in the official way of writing proper names
If a change takes place in the official way of spelling a geographical or other name that is being used as a proper or characterizing name for a formal geological unit, the new version is to be used provided the change is insignificant and will not lead to misunderstanding. If the type section, type locality or type area is given an entirely new name on new editions of topographical maps, the name originally assigned to the unit is to be retained.
2.3 Names of informal units
2.3.1 The reason for having informal units, their use and status
Informal units can be introduced for temporary use (a) when carrying out geological mapping, (b) during ongoing scientific, engineering or economic investigations, (c) when preliminary research results are being published, (d) when writing internal reports, theses, etc., that are not going to be published, and (e) for more lasting use when for various reasons it is not practical to erect formal units.
2.3.3 Ways of writing informal names
Informal names are written in Norwegian according to usual orthographical rules. If the name is understood and used as an ordinary type designation it is a collective name and is to be written with a lower-case initial. If the informal designation is understood and used as the name for a specific entity (unit), it is a proper name and is to be written with an upper-case initial. For example, the informal name Grefsensyenitt (the Grefsen syenite) which, when written in this way, is the proper name for a specific body (lithodeme) of syenite at Grefsen. The petrographic variety of this syenite is also found in other places and may then be called grefsensyenitt as a collective name (in English the collective name should include the word 'type' - Grefsen syenite-type), i.e. with a lower case initial letter in Norwegian, but not in English.
2.4 Rules for erecting formal geological units
The erection of any formal geological unit must always be based on certain fundamental information about the unit. This is crucial if unambiguous definitions are to be achieved. NSK advises authors to follow the recommendations listed in Sections 2.4.1 to 2.4.14, when erecting a formal unit.
2.4.1 Objective The reasons and practical need for erecting a new formal geological unit, changing the rank and definition of an existing unit, or completely rejecting an already defined and named formal unit should be clearly stated.
.2.4.2 Historical background and previous investigations
When a new formal unit is being erected, previous investigations and any informal designations of the unit are to be referred to. If the introduction of a new name is desired, reasons are to be given for why the old name of the unit should be changed.
2.4.3 Category and rank The category and rank of geological units are to conform with the main definitions given in this Code. It is very important that the unit is investigated sufficiently thoroughly to enable it to be erected in the correct category, class and type, and with an appropriate rank. The areal extent of the unit is particularly important in this respect. This also applies to units on the continental shelf.
The choice of name must conform with the rules given above (Sections 2.1 and 2.2) and, if necessary, with the special rules relating to the category and unit in question, and those applicable for units on the continental shelf. Responsibility for ensuring that a proposed proper or characterizing name has not been used previously, rests with the proposer. Previous usage will be checked prior to any approval of the name by NSK.
2.4.5 Type section, type locality, type area, reference section
The definition of a formal geological unit should be based on its occurrence in one or more type sections, a type locality or a type area (its stratotype). The occurrence of the unit here has to be as far as possible representative for that found throughout its area of distribution.
Knowledge about their age plays no direct role in definition and erection of formal geological units, other than time units. The age of a geological unit will nonetheless be of considerable interest and should be mentioned.
For the sake of clarity newly-erected geological units should be correlated with corresponding units outside the type area. The basis for the correlation is to be given.
2.4.13 Approval by the Norwegian Committee on Stratigraphy (NSK)
When formal geological units are being erected, the basis for their establishment is to be reported to NSK to provide the grounds for possible approval of the proposed name. The purpose of this requirement is to ensure that the unit is (a) adequately defined according to the rules laid down by ISSC (1976) and this Code, (b) given an unambiguous name which is constructed and written according to the rulings of this Code, (c) recorded in the register of names at the Norwegian Committee on Stratigraphy, and thereby secured priority, protection and status as a formal name. ...
For a unit to become valid as a formal unit it must be defined in a publicly available scientific journal, map description, published well description, or a guidebook printed in a large edition. ...
2.5 Amendment and rejection of formal units
2.5.1 Amendment of formal units
Formally erected geological units can be redefined or revised.
A unit can be changed in category, in which case its proper (geographical) name usually has to be changed. If a unit is redefined to a closely related category, for example from a metamorphic lithodemic unit to a metamorphic lithostratigraphical unit, the original proper name can be retained.
If a unit is divided into two or more units having the same rank as the original one, the original proper name must not be used for any of the new ones. The proper name of the original unit may be retained if the rank of that unit is raised following the new division.
2.5.2 Rejection of formal units
A formal unit may be rejected, or its use abandoned, if it proves to (a) be equivalent to a previously formally defined unit, (b) be defined in the wrong category, (c) not have any application, and (d) be used in many different ways. The proper name of a formal or an informal unit that has been rejected may be used for a subsequently newly erected unit if a long period has passed after the name was used in its original meaning.
Amendments and rejections of formal unit names are to be approved by NSK prior to publication.
3 Geological units defined on the basis of material content or other physical properties
3.2 Lithostratigraphical units
3.2.1 General properties and rules
... A lithostratigraphical unit is a body of sedimentary, volcanic, metamorphosed sedimentary or metamorphosed volcanic beds delineated on the basis of characteristic lithological properties and stratigraphical position. Lithostratigraphical units conform to the "Law of Superposition", i.e. younger beds are deposited on older ones.
Lithostratigraphical units are defined independently of inferred geological history, mode of genesis or biological development. Their boundaries are in principle independent of time horizons, and most are time-transgressive. ...
Lithostratigraphical units serve as units when geological mapping is being carried out. They are used in the field and when writing descriptions, elucidating the geological history and assessing economically exploitable deposits (oil, ores, minerals, gravel, groundwater, etc.).
Lithostratigraphical units are, in decreasing order of rank, supergroup, group, formation, member and bed/flow. The formation is the fundamental unit.
3.2.2 Formation (Formasjon)
126.96.36.199 A formation is a body of rock or superficial deposits occurring as part of a succession. It is characterized by its stratigraphical position in the succession and by a set of characteristic lithological properties that distinguishes it from adjacent units of rock or superficial deposits. Formations often have a three-dimensional shape such as a sheet, slice, lens, wedge or tongue.
188.8.131.52 Formation is the fundamental formal unit for lithostratigraphical classification and nomenclature. Formations have a practical use when geological maps are being made and when the geological, geophysical and geotechnical properties of an area and its geological history are being described. A formation can be subdivided into members, and two or more formations can be defined as a group.
184.108.40.206 A formation must be mappable at the surface or traceable in the subsurface. A formation exposed at the surface has to be mappable on ordinarily available base maps (official topographical maps, land-use maps, or privately produced, but openly available maps). A formation must also be capable of being portrayed on specially constructed maps, or sections on the same scale, intended to show its extent and three-dimensional form in the subsurface. A particularly thin formation can be portrayed as a single, thin line on maps and sections. A formation is mapped on the surface and recorded in the subsurface by ordinary field geological methods, excavation of sections, drilling and geophysical measurements.
220.127.116.11 ... A formation is recognized by at least one lithological property, such as mineral composition, chemical composition, fossil content, structures, grain size and other textural features. The boundaries of a formation may be lithologically sharp, or they may need defining by a change in at least one lithological property if there is a gradual transition between two adjacent lithostratigraphical units. A formation may be characterized by electrical, thermic, magnetic, radiometric, hydraulic, seismic and other physical characteristics which derive from lithological properties. It may contain two or more unconformity surfaces, which may, for example, be reflected by a lack of continuity in fossil content. The fossil content of a formation may define one or more biozones.
3.2.3 Group (Gruppe)
18.104.22.168 A group is a stratified body of rock or superficial deposits comprising two or more formations, or a corresponding number of informal lithostratigraphical units.
22.214.171.124 The thickness and extent of a group is determined by the total thickness and regional extent of the formations or informal lithostratigraphical units constituting it. A group need not consist of the same formations throughout its area of distribution (Fig. 4).
126.96.36.199 A group is mappable at the surface and traceable in the subsurface with the help of geological and geophysical methods. It is usually a practical lithostratigraphical unit for portrayal on small-scale regional maps.
188.8.131.52 ... The formal or informal lithostratigraphical units in a group are closely related as regards geological evolution and mode of genesis. There may also be a certain similarity in Lithology, but this is not essential. ...
184.108.40.206 A group may change character regionally, making it more practical to designate it as a formation in an area away from its type area. The proper name of the originally defined group can be retained even though the stratigraphical rank in such areas is changed to formation. In certain cases it may be desirable to divide the group into subgroups (undergrupper). These can be formal having their own names, or informal having designations such as "lower", "middle" and "upper" (Section 2.3.2).
3.2.5 Member (Ledd)
220.127.116.11 A member is a body of rock or superficial deposits that occurs in a stratified formation.
18.104.22.168 The extent of a member is usually less than the extent of the formation of which it forms a part. A member can pass laterally from one formation into another.
22.214.171.124 A member need not be mappable on the same base map as is required for the portrayal of the formation of which it forms a part. It may be traceable in the subsurface using geological and geophysical methods.
126.96.36.199 A member is defined when it is desirable to distinguish a particular lithostratigraphical part of a heterogeneous formation. A formation need not be subdivided into members. The entire formation or parts of it may be erected as members. A member may consist of beds or flows, but cannot contain other members.
3.2.6 Bed (Lag), Flow (Strøm)
188.8.131.52 A bed is the smallest formal lithostratigraphical unit in sedimentary sequences. A flow is the correspondingly smallest unit in volcanic rocks and deposits formed by flowing lava or ash.
184.108.40.206 Beds and flows have lithostratigraphical rank next beneath members, but may also be formally erected in formations lacking formally erected members.
220.127.116.11 Beds and flows are usually not mappable other than on special, particularly large-scale maps. They can be portrayed on sections of suitable scale. They may be traceable in the subsurface using geological and geophysical methods.
18.104.22.168 A bed usually represents a single depositional event in a sedimentary sequence and is characterized by composition, structure and texture. A flow is a volcanic extrusive rock formed during a single eruption. It is characterized by composition, structure, texture, palaeomagnetism and other properties, ...
3.3 Lithodemic units
3.3.1 General properties and rules
A lithodemic unit consists of one or more bodies of igneous rocks which may be plutonic, intrusive or extrusive rocks and/or strongly metamorphosed and deformed rocks (Figs. 1, 5). The unit is defined entirely on the basis of lithological character. In contrast to lithostratigraphical units, the classification of lithodemic rocks does not follow the principle of younger rocks being formed above older ones. Lithodemic units are therefore erected in areas where rocks do not succeed one another in compliance with the "Law of Superposition", or where it is very. difficult to prove such a relationship.
Lithodemic units serve as units when geological mapping is being carried out in areas where the bedrock lacks stratification. They are used during field work, when writing descriptions, elucidating the geological history and assessing economically exploitable deposits. Contacts with other geological units may be sedimentary, intrusive, metamorphic or tectonic in origin.
Lithodemic units are, in decreasing order of rank, supersuite, suite and lithodeme. The lithodeme is the fundamental unit. Complex is not ranked, but will usually correspond in size to suite or supersuite. ...
Formal lithodemic units should only be defined and erected if they serve a practical purpose. Names of informal lithodemic units are not to be constructed using a geographical name (or an alternative name in the case of the continental shelf) and a formal hierarchical unit designation.
3.3.2 Lithodeme (Litodem)
22.214.171.124 A lithodeme is a body of intrusive, volcanic or highly metamorphosed and/or thoroughly deformed rock that lacks primary structures. It is characterized by having a set of lithological properties that distinguishes it from adjacent geological units.
126.96.36.199 Lithodeme is the fundamental formal unit in lithodemic classification and nomenclature. Two or more lithodemes of the same class can be defined as a suite.
188.8.131.52 No limitations are placed on the dimensions of a lithodeme except that it must be mappable at the surface or traceable in the sub-surface.
184.108.40.206 A lithodeme should be mappable at the surface or traceable in the subsurface using geological and geophysical methods. It should be mappable on ordinarily available base maps (official topographical maps, land-use maps, and privately-produced, but openly available maps).
220.127.116.11 A lithodeme consists of a rock that can be identified by its lithological properties using field geological methods. ... A lithodeme may be an intrusive rock occurring, for example, as a pluton, diapir, stock, laccolith, sheet or plug, a body of volcanic rocks which have mutually complex boundary relationships, or a body of strongly metamorphosed rock. ... A lithodeme may be characterized by electrical, thermic, magnetic, radiometric, hydraulic, seismic and other physical characteristics derived from its lithological properties.
18.104.22.168.a Lithodeme corresponds in rank to formation in the lithostratigraphical classification system, also when used informally on maps or in descriptions.
22.214.171.124.b A lithodeme may change its character regionally. It may therefore be more practical to designate the unit as a suite beyond its type area; the original proper name may then be retained (see Section 2.5.1).
3.3.3 Suite (Suite)
126.96.36.199 A suite is a lithodemic unit consisting of two or more lithodemes, or informal lithodemic units. Individual lithodemes in a suite must belong in the same class, i.e. be either igneous or metamorphic rocks.
188.8.131.52 Suite is a formal lithodemic unit ranking next above lithodeme. Two or more suites of the same or a different class can be defined as a supersuite.
184.108.40.206 A suite usually has a regional extent, or consists of a few distinct units which together have a regional extent.
220.127.116.11 A suite is mappable at the surface and traceable in the subsurface using geological and geophysical methods.
18.104.22.168 A suite consists of formal lithodemes and/or informal, unnamed lithodemic units that belong to the same class of rocks. These may be either igneous or metamorphic (including metasomatic and highly deformed rocks). A suite may therefore be, for example, a platonic, intrusive, dyke or metamorphic suite. The individual formal or informal units in a suite have one or more characteristic features in common that often unite them in a common geological history or mode of origin.
22.214.171.124 Suites are only given formal names, this being done in accordance with the "general rules for naming and defining geological units". The name may consist of a geographical name (or an alternative name in the case of the continental shelf) between the words "the ... Suite", but a descriptive term, such as "Intrusive" or "Metamorphic", may in addition be placed in front of "Suite".
126.96.36.199.a Suite corresponds in rank to group in the lithostratigraphical classification system.
188.8.131.52.b A suite may change in character regionally, making it more practical to designate the unit as a lithodeme in areas beyond its type area. ...
3.3.5 Complex (Kompleks)
184.108.40.206 A complex is a lithodemic unit consisting of a mixture or assemblage of rocks belonging to two, or all, of the classes of rocks, i.e. igneous, sedimentary and metamorphic rocks.
220.127.116.11 Complex has no rank in the lithodemic classification system.
18.104.22.168 No limitation is placed on the dimensions of a complex, but it generally has a regional extent.
22.214.171.124 A complex is mappable at the surface and traceable in the subsurface using geological and geophysical methods.
126.96.36.199 The individual, associated bodies of different rock units making up a complex may be formally named lithodemes, lithostratigraphical units, and/or informal and unnamed lithological units. They have often been deformed together to form a complicated structural pattern, but this is not a prerequisite. A complex of large regional extent may contain other complexes of smaller areal distribution.
188.8.131.52 A complex is given a formal or an informal name in accordance with the "general rules for naming and defining geological units" (Chap. 2). Names made up of a geographical name between the words "the ... Complex" should preferably only be used for formally defined complexes (see Section 2.3.2).
184.108.40.206.a A complex is a practical mapping entity in areas where it is difficult or impractical to distinguish individual lithodemic or stratigraphical units on the map scale in question.
220.127.116.11.b A complex is often comparable in size to a suite or supersuite.
18.104.22.168.c A volcanic complex is an assemblage of different kinds of volcanic rocks and associated intrusive and weathering products. Volcanic complexes or intrusive volcanic complexes that are included in a thick sequence of sedimentary rocks can be defined together with these as a supergroup.
22.214.171.124.d A structural complex is an assemblage of different kinds of rocks intermixed by tectonic processes (Fig. 1).
ISSC (International Subcommission on Stratigraphic Classification of IUGS Commission on Stratigraphy) 1976: International Stratigraphic Guide: A Guide to Stratigraphic Classification, Terminology and Procedure (ed. Hedberg, H.D.), 200 pp. John Wiley & Sons, New York.
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