The Bravo Lake Formation is a mafic

volcanic belt A volcanic belt is a large volcanically active region. Other terms are used for smaller areas of activity, such as volcanic fields. Volcanic belts are found above zones of unusually high temperature () where magma is created by partial melting ...

and large igneous province located at the northern margin of the Trans-Hudson orogeny on central

Baffin Island Baffin Island (formerly Baffin Land), in the Canadian territory of Nunavut, is the largest island in Canada and the fifth-largest island in the world. Its area is , slightly larger than Spain; its population was 13,039 as of the 2021 Canadia ...

Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' ...

, Canada. It is exposed along a nearly continuous east–west passage for and changes in stratigraphic thickness from 1 to 2.5 kilometers.Central Baffin Island 4-D Project - Projects
: Paleoproterozoic mafic magmatism in central Baffin Island. Retrieved on 2007-10-18 The

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

is a rare alkaline-suite that formed as a result of submarine rifting during the Paleoproterozoic period.Volcanology and geochemistry of the Bravo Lake Formation, Baffin Island, Nunavut
Retrieved on 2007-10-18 The Bravo Lake Formation is surprisingly undeformed by the Himalayan-scale forming event during the Trans-Hudsonian orogeny. The

stratigraphy Stratigraphy is a branch of geology concerned with the study of rock (geology), rock layers (Stratum, strata) and layering (stratification). It is primarily used in the study of sedimentary rock, sedimentary and layered volcanic rocks. Stratigrap ...

of the Bravo Lake Formation starts with a basic section of iron-oxide rich sandstones, psammites, and semi- pelites which cover a series of deformed pillow lavas which expand in viscosity towards the west, and volcanic/clastic deposits and ultramafic sills. The lower volcanic section is covered by garnet and diopside bearing calc–silicate layers and finely layered metasediments composed of coarse-grained actinolite, hornblende and

biotite Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula . It is primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more alumino ...

followed by pelites and semi-pelites that are intruded by separate sills. In the Ridge Lake area, the volcanic belt includes an interlayered series of

amphibolite Amphibolite () is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flaky ...

, gabbro, iron formation, sulfidic schist and metasediments. Geochemical results of pillow lavas and chill boundaries along five transects across the volcanic belt suggest the existence of three chemically different magma types within the Bravo Lake Formation. Lavas of the

display

geochemical Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the e ...

characteristics similar to modern ocean-island–basalt groups. They range from moderately to intensely fractionated. REE-profiles are similar to those from tholeiitic basalts to extremely

alkaline In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a base (chemistry), basic, ionic compound, ionic salt (chemistry), salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as ...

lavas in Hawaii.

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Paleoproterozoic alkaline magmatism of the Bravo Lake Formation of central Baffin Island, Nunavut
Volcanic belts Large igneous provinces Volcanism of Nunavut Geography of Qikiqtaaluk Region Geography of Baffin Island Proterozoic volcanism {{canada-geologic-formation-stub

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