Bravo Lake Formation

The '''Bravo Lake Formation''' is a [[mafic]] [[volcanic belt]] and [[large igneous province]] located at the northern margin of the [[Trans-Hudson orogeny]] on central [[Baffin Island]], [[Nunavut]], [[Canada]]. It is exposed along a nearly continuous east-west passage for {{convert|120|km|mi|0|abbr=on}} and changes in stratigraphic thickness from 1 to 2.5 kilometers. The [[Formation (geology)|formation]] is a rare alkaline-suite that formed as a result of submarine [[rift]]ing during the [[Paleoproterozoic]] period. The Bravo Lake Formation is surprisingly undeformed by the Himalayan-scale forming event during the Trans-Hudsonian orogeny. The [[stratigraphy]] of the Bravo Lake Formation starts with a basic section of iron-oxide rich [[sandstone]]s, [[psammite]]s, and semi-[[pelite]]s which cover a series of deformed [[pillow lava]]s which expand in viscosity towards the west, and volcanic/clastic deposits and [[ultramafic]] [[Sill (geology)|sills]]. The lower volcanic section is covered by [[garnet]] and [[diopside]] bearing calc-silicate layers and finely layered metasediments composed of course-grained [[actinolite]], [[hornblende]] and [[biotite]] 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]], [[gabbro]], [[Banded iron formation|iron formation]], sulfidic [[schist]] and metasediments. Geochemical results of [[pillow lava]]s 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 [[volcanic belt]] display [[Geochemistry|geochemical]] characteristics similar to modern ocean-island-basalt groups. They range from moderately to intensely fractionated. [[Rare earth element|REE-profiles]] are similar to those from [[tholeiitic basalt]]s to extremely [[alkaline]] lavas in [[Hawaii]]. ==See also== {{Portal|Volcanism of Canada}} *[[List of volcanoes in Canada]] *[[Volcanism of Canada]] *[[Volcanism of Northern Canada]] *[[Geography of Nunavut]] ==External links== *[http://gac.esd.mun.ca/gac_2003/search_abs/sub_program.asp?sess=98&form=10&abs_no=439 Paleoproterozoic alkaline magmatism of the Bravo Lake Formation of central Baffin Island, Nunavut] {{coord missing|Nunavut}}