The Klein Suite was introduced in the Kuujjuaq and Ungava Bay area (Simard et al., 2013) to group all metamorphosed mafic and ultramafic rocks of the Laporte Supersuite. The Laporte Supersuite includes Paleoproterozoic volcano-sedimentary rocks of the Rachel-Laporte Lithotectonic Domain, which represents the eastern part of the New Quebec Orogen. The Klein Suite was continued southward in the Saffray Lake (Lafrance et al., 2014) and Jeannin Lake (Charette et al., 2016) areas. Units of the Klein Suite were also standardized southward to the Griffis Lake area (sheet 23P04), as part of a synthesis of the Southeastern Churchill Province (SECP; Lafrance et al., 2018). Bilodeau (2018) also mapped the Klein Suite in the Kuujjuaq area.

Mafic rocks now assigned to the Klein Suite were first mapped by Sauvé (1957, 1959), Gélinas (1958a, 1958b, 1959), Fahrig (1964), Dimroth (1966), Dressler (1974, 1979), Baragar (1967), Frarey (1967), Penrose (1978), Clark (1978, 1980) and Girard (1995). These observations were incorporated into the SIGÉOM compilation map by Thomas Clark between 2009 and 2016 and used to supplement the description of several units. Units have been standardized as part of a synthesis of the SECP (Lafrance et al., 2018; Lafrance and Vanier, 2021). In the Deborah Lake area (sheet 23P05), Girard (1995) assigned amphibolite, metatuff and gabbro units to the Deborah Formation. This unit has also been abandoned and the rocks mentioned are included in units pPkle1a, pPkle1b and pPkle3 of the Klein Suite, respectively.

The Klein Suite groups Paleoproterozoic metamorphosed mafic and ultramafic rocks of the Rachel-Laporte Lithotectonic Domain. It consists of three informal units: 1) amphibolite and metabasalt (pPkle1); 2) metamorphosed ultramafic rocks (pPkle2); and 3)  metagabbro and glomerophyric metagabbro. Intrusive units are most commonly conformable within amphibolites and metasedimentary rocks of the Laporte Supersuite. However, sharp crosscutting has also been observed in places.

Unit pPkle1 consists of four informal units: 1) fine to very fine-grained amphibolite, possibly of volcanic origin (pPkle1a); 2) massive or pillow metabasalt and mafic or intermediate metavolcaniclastics (pPkle1b); 3) highly altered carbonate-quartz amphibolite (pPkle1c), and 4) amphibolite associated with some paraschist (pPkle1d). The different authors who worked in the Rachel-Laporte Domain did not always distinguish these differences in composition or texture; therefore, some outcrops were assigned to the undivided amphibolite unit (pPkle1). Unit pPkle1 could therefore include some medium to coarse-grained amphibolite of possible intrusive origin similar to unit pPkle3. Very fine-grained amphibolite is interpreted as effusive in origin, while coarser-grained rocks may be intrusive in origin. Observed relationships between these two facies suggest that coarser-grained amphibolites may be sills associated with lava.

Klein Suite 1a (pPkle1a): Fine to Very Fine-Grained Amphibolite

Amphibolites of subunit pPkle1a are banded, massive or schistose, dark green or black grey and fine to very fine grained, rarely medium grained. Banding is caused by variations in ferromagnesian mineral content. In thin sections, these rocks are characterized by a well-developed oriented granoblastic texture. They are composed of small hornblende prisms (50-85%) aligned in a fine-grained matrix of plagioclase ± quartz crystals that fill the pores. In places, hornblende also occurs as poikiloblasts more or less orientated in foliation. Some samples also contain 10-25% intergrown actinolite crystal clusters. Actinolite also replaces hornblende or clinopyroxene (uralitization), which is only preserved locally.

Amphibolite has been affected by retrograde metamorphism of regional importance, but generally quite low. This interpretation is supported by the common presence of chlorite associated with hornblende, more or less sericitized plagioclase, and the presence of carbonate. The latter fills fracture filling or is interstitial, replacing hornblende or plagioclase. Biotite and garnet are less common, but represent up to 10% of the rock locally. Staurolite has also been recognized in amphibolites around the Rénia and Boulder complexes. Almost all samples observed in thin sections contains sphene, apatite and opaque minerals (ilmenite ± magnetite). Epidote, zircon, allanite, tourmaline and sulphides are also present as accessory phases.

Klein Suite 1b (pPkle1b): Massive or Pillow Metabasalt and Metavolcaniclastics

Subunit pPkle1b is similar to subunit pPkle1a, but is distinguished by the presence of layers where primary textures, such as pillows and vesicles, are preserved. Pillows are usually elongated in foliation and are 5 cm to 10 cm wide by 20 cm to 40 cm long. Due to deformation, stratigraphic polarities are generally impossible to determine. Layers of intermediate to mafic pyroclastic rocks and layers containing ovoid mafic fragments, which may represent pillows having hyaloclastic margins filled with quartzs, have also been described locally.

Klein Suite 1c (pPkle1c): Highly Altered Carbonate-Quartz Amphibolite

Klein Suite amphibolites are commonly cut by discontinuous and boudinaged carbonate or quartz veins. Amphibolites locally show strong carbonate and silica alteration in the form of lenses that, when sufficiently numerous, give the rock a brecciated texture. In the Bay aux Feuilles area, Sauvé (1959) recognized a unit of altered amphibolite that Simard et al. (2013) assigned to subunit pPkle1c.

Klein Suite 1d (pPkle1d): Amphibolite With Some Paraschist

Centimetric to metric layers of rocks belonging to various metasedimentary units of the Freneuse Suite are in places interstratified with amphibolites of the Klein Suite. Some areas with a larger proportion of these paraschist layers were assigned to informal subunit pPkle1d in the Bay aux Feuilles (Sauvé, 1959) and Thévenet Lake (Gélinas, 1958a) areas.

Klein Suite 2 (pPkle2): Metaperidotite and Metapyroxenite

Thickness and distribution

The Klein Suite covers an area of ~1373 km² within the Rachel-Laporte Tectonic Domain. Amphibolites of unit pPkle1 (including its subunits) is the dominant litholgy of the suite (1110 km²). They form layers and klippes up to 5 km wide, interstratified with metasedimentary units of the Freneuse Suite. Ultramafic rocks of unit pPkle2 unit and metagabbros of unit pPkle3 form hectometric to kilometric intrusions. On the eastern and northern edge of the Wheeler Complex, in the Jeannin Lake area, there are thicker amphibolite and metagabbro sequences that are nearly 10 km wide.

Dating

The ~1884 Ma preliminary age obtained in a coarse-grained gabbro sample is similar to those obtained in glomerophyric gabbro sills of the Gérido Intrusive Suite (Montagnais Supersuite), in the Labrador Trough. The ages obtained in the Gérido Intrusive Suite range from 1884 Ma to 1874 Ma (Machado et al., 1989; Findlay et al., 1995; Wodicka et al., 2005).