We review currently available Canadian and international lithostratigraphic and lithodemic schemes and find most of them inadequate for classifying intrusive and strongly metamorphosed rocks of Canada and beyond. A new system is proposed, one that unifies, complements, and extends components of the revised North American Stratigraphic Code, the British Geological Survey Rock Unit Classification System of 2021, and the International Stratigraphic Guide of 1999. This new Cooperative Lithodemic and Stratigraphic System (CLASS) is intended to serve as a practical guide to geoscientists who need to classify and report on lithodemic units in North America and has broad applicability to other jurisdictions. It is built with database management practices in mind and employs the concept of inheritance of root characteristics between seven formal rock unit ranks, which will allow incorporation of the scheme into compact object-oriented and relational databases designed for purpose. Broad application of CLASS, especially to historically problematic lithodemic units, should help to foster jurisdictional interoperability, data sharing, global compilations, and thematic studies. At the heart of this proposed system is a subdivision and accompanying nomenclature that allows classification of rocks into seven formal ranks. Following the well-established lithostratigraphic supergroup, group, subgroup, formation, member, submember, and bed approach, CLASS proposes three classes of lithodemic subdivisions for formally naming lithodemic rock units.

The Rottenstone Domain (RD) is a complex lithotectonic supracrustal belt of the Paleoproterozoic Trans-Hudson Orogen in Saskatchewan, Canada, located between the Archean Hearne craton and the juvenile Paleoproterozoic Reindeer Zone (RZ). Its evolution and crustal affinity have been under considerable debate in the past few de-cades, with most interpretations considering it to be part of RZ, but some hinting that certain elements might have affinities to the Archean hinterland. On the basis of bedrock mapping, U-Pb, Sm-Nd and lithogeochemical data, the rocks of the southwestern RD were subdivided into several lithodemic entities, which were used to reconstruct a plate tectonic framework for the western part of the Trans-Hudson Orogen during Orosirian time.A U-Pb zircon crystallization age of 2518 +/- 6 Ma and depleted mantle model age (TDM) of 2.8 Ga for an augen granite confirmed that the western part of RD is part of the Hearne craton. A newly discovered structural inlier at the eastern boundary of RD consists of a central unit of 2045 +/- 9 Ma augen granite, with TDM ages between 2.8 and 2.6 Ga, that was intruded into gneissic granite with a TDM of 3.3 Ga. The augen granite was interpreted as representing a rift-related granite, emplaced into Archean rocks of the Hearne craton. Two lithotectonic as-semblages, one dominated by feldspathic quartzite and psammite the other by migmatitic psammite-psammopelite, are in structural contact with the granitic inliers and have model ages of 2.6-2.4 Ga. One of the feldspathic quartzite samples contains detrital zircon age modes at 1910 and 1860 Ma, and lesser Archean modes. Both assemblages were likely deposited in a forearc basin to the 1.865-1.850 Ga Wathaman continental arc.Recognition of Archean components and metasedimentary assemblages with older model ages than those in the RZ to the east, suggest that this southern part of RD is more closely affiliated with the Hearne craton. The eastern edge of RD coincides with a mylonite zone (Howard Lake shear zone), which likely represents a fundamental, although multiply reactivated, structural break separating Archean granitoids and structurally overlying metasedimentary rocks from rocks of the more juvenile Reindeer Zone.

The Peter Lake domain, a component of the Hearne craton in Saskatchewan, includes several intrusive complexes ranging in age from 2.70 to 1.83 Ga. Two gabbroic complexes (Swan River and Porter Bay) together represent one of the largest accumulations of Precambrian mafic intrusion, both metamorphosed at amphibolite facies. Sulfide-poor PGE occurrences are found in both complexes and share many textural and lithological characteristics with magmatic contact-type PGE–(Ni–Cu) deposits such as the chaotic Lac des Iles pluton and with layered stratiform deposits of large layered intrusions such as Bushveld or Stillwater. Lithologically, both complexes are dominated by leucocratic gabbronorite and gabbro, locally characterized by cumulate layering, cross-bedding, brecciated, and pegmatitic textures. U–Pb zircon crystallization ages between 2562 and 2560 Ma were obtained for the Swan River complex. sulfide formation is interpreted to be of magmatic origin rather than remobilized, as had been speculated by exploration geologists, and is therefore of the same age as the host gabbro. Geochemical data support the interpretation of a mantle plume origin in a subduction environment for the Swan River complex. The Porter Bay complex is much more restricted in areal extent and a leucocratic gabbronorite yielded a U–Pb zircon age of 1913 ± 1 Ma, which is interpreted as the crystallization age and the time of sulfide formation. Major and trace element geochemical data of Porter Bay complex rocks show a considerably more evolved character than the Swan River complex, and is interpreted as indicating emplacement in a continental arc environment.

We report preliminary zircon U-Pb geochronological results from a suite of plutonic rocks from the Peter Lake Domain along northern Reindeer Lake. The crystallization age of a foliated granite is interpreted to be ca. 2.58 Ga, but it also contained inherited material older than 2.62 Ga. A sample of sulphide-bearing gabbro is shown to have crystallized at 2562 ±3 Ma, linking it with the Archean Swan River Complex of mafic rocks. A foliated gabbro in the Zengle Lake area yielded one concordant zircon fraction with an age of 2435 ±9 Ma. Further analyses are pending to determine the significance of this age. A massive leucogabbro, collected west of the Patterson Island channel, is identified as part of the Patterson Island pluton, as it yielded a preliminary crystallization age of 1.91 Ga. More analyses are being conducted to further refine this age estimate. A megacrystic quartz monzonite sample, also from Zengle Lake, is interpreted to have crystallized at ca. 1.85 Ga. Some zircon inheritance, with minimum ages of 1.9 to 2.1 Ga, has been observed in this sample. A sample of megacrystic monzogranite on Fontaine Island gave an age of 1865 +4/-2 Ma. A rhythmically layered anorthosite gabbro was collected southwest of the Feaviour Peninsula and yielded an upper intercept age of 1854 +5/-4 Ma. A quartz diorite collected near Crane Island is tentatively ascribed to the Wathaman Batholith age intrusions, as a single, concordant zircon fraction gave an age of 1.85 Ga. Further fractions are pending. A syenogranite from northwest of Patterson Island, yielded the youngest plutonic age so far reported in the Peter Lake Domain at 1829 ±5 Ma.

A geological transect at 1:20 000 scale was mapped across the southeast margin of the Peter Lake Domain along the west shore of Reindeer Lake, encompassing part of the 2.562 Ga Swan River Complex. It is less extensive than indicated by previous workers and is intruded by large masses of monzonitic to granitic rocks. The Swan River Complex intruded subordinate mafic to felsic volcanic and migmatitic sedimentary rocks that were metamorphosed at upper amphibolite facies metamorphic grade during Neoarchean times. It comprises two distinct intrusive suites: an older and more deformed and recrystallized gabbroic suite and a younger leucogabbroic suite. These are correlated respectively with the Warner Lake gabbroic suite and the Love Lake leucogabbroic suite in the southwestern part of the Peter Lake Domain. Both have well-preserved primary igneous features common in other layered intrusions, including modal rhythmic layering, cross-bedded layering, colliform layering and layered autoliths. The Lueaza River granitoid, which is closely associated and similar in age to the Warner Lake gabbroic suite of the Swan River Complex, is characterized by foliated megacrystic monzogranite and dioritic to granitic orthogneisses. The Patterson Island Pluton forms part of a larger and more extensive monzonitic-syenitic suite, which intruded the Swan River Complex and is here tentatively correlated with the 2.54 Ga monzonitic intrusion in the Peter Lake area. The pluton consists of an outer megacrystic monzonite phase and an inner megacrystic syenite phase. Both phases have primary igneous layering preserved and grade locally into minor gabbro and leucogabbro. Massive to weakly foliated syenogranite to alkali feldspar granite of unknown age intruded most of the previous lithologies. Some of the granitoid rocks may be Archean; others may be related to the 1.86 Ga Wathaman Batholith, which underlies the southeastern portion of the transect. Two new sulphide occurrences were discovered near the 'Ant' Cu-Ni-Pt-Pd showing.

Abstract The Love Lake Leucogabbro is a large mafic to ultramafic intrusion within the southwestern Swan River Complex of the mostly Archean Peter Lake Domain. This pluton comprises a main phase described by previous workers as leucogabbro,and several minor mafic to ultramafic ones. This paper summarizes,the results of a B.Sc. Honours thesis on the petrography, geochemistry, and metamorphism of the Love Lake leucogabbro. Petrographic and electron microprobe,analysesshowed,that the main phase of the pluton is amphibolitized leucogabbronorite; leucogabbro, gabbro, and clinopyroxene norite are minorcomponents. The Love Lake Leucogabbro has been affected by an upper amphibolite faciesmetamorphic event, likely during the Archean, as well as a later lower amphibolite to upper greenschist facies event, probably coinciding with the Paleoproterozoic Trans-Hudson Orogeny. Whole rock major and trace element analyses of the gabbronorite suggest it was derived from a cogenetic magma

The largely Archean Peter Lake Domain is wedged between the Wollaston Domain to the northwest and the Paleoproterozoic Wathaman Domain to the southeast, bounded in part by the Needle Falls Shear Zone and the Parker Lake Shear Zone, respectively. Its perceived high platinum group element potential and ambiguous geological history and setting prompted the Saskatchewan Geological Survey to initiate a detailed three-year mapping project. Historically, the domain has been subdivided into three main components: the Peter Lake Complex, its high-strain equivalents called the Parker Lake Gneisses, and a low-grade sedimentary succession, the Campbell River Group. In the first year of the project, a 40 km long and 10 to 15 km wide transect flanking Highway 905 was mapped between Courtenay Lake and the Wathaman River. The poorly exposed northern half of the map area comprises large intrusions of massive to weakly foliated syenogranite, part of which is fluorite- bearing, and a dioritic to gabbroic suite. The southern half of the domain is better exposed and is underlain by massive to mylonitic, mafic to felsic plutonic rocks, including leucogabbroic to anorthositic, gabbroic, and dioritic suites, as well as younger granodioritic, monzonitic, and granitic intrusive suites. The Love Lake leucogabbro contains rare examples of well preserved primary igneous layering. Locally abundant fine-grained mafic xenoliths in the pluton have a tectonic foliation predating the fabric in the host. Several slivers of upper amphibolite facies migmatitic supracrustal rocks are between Peter Lake and the Wathaman River, as well as a 0.2 to 1.5 km outlier of lower amphibolite facies Campbell River Group quartzite and argillite containing well preserved primary sedimentary structures including crossbedding, and ball-and-pillow structures. The structural history included at least four ductile deformational events, two main regional metamorphic events, and late brittle faulting. Several outcrops contain disseminated iron sulphides, chalcopyrite, and rare azurite. Geochemical analyses of grab samples have not returned significant values of gold, copper, and/or platinum group elements.