Gunflint iron formation
The Gunflint chert (1.88 Ga ) is a sequence of banded iron formation rocks that are exposed in the Gunflint Range of northern Minnesota and northwestern Ontario along the north shore of Lake Superior. The Gunflint Chert is of paleontological significance, as it contains evidence of microbial life from the Paleoproterozoic. … See more The Gunflint Iron Formation is a banded iron formation, composed predominantly of dense chert and slate layers interbedded with ankerite carbonate layers. The chert layers can be subdivided into black layers (containing organic … See more The most abundant organisms in Gunflint are filaments found in stromatolitic fabrics, and typically range from 0.5-6.0 μm in diameter and up to several hundred microns in … See more Filamentous microorganisms within the Gunflint Chert represent a mixed population of photosynthetic cyanobacteria and iron oxidizing bacteria. On the outcrop scale, the filamentous Gunflint cyanobacteria form meter-scale stromatolitic domes, which are discernible along … See more Geologist Stanley A. Tyler first examined the Gunflint Range in 1953 and observed red iron banded formations and black chert, noting probable stromatolites, though he would … See more The Gunflint chert microfauna is mid- to late-Paleoproterozoic in age (approximately 1.878 Ga ± 1.3 Ma, as determined by Uranium-Lead dating techniques). This age has fluctuated as dating techniques have become more accurate and … See more Spheroidal spore-like bodies within the Gunflint Chert are found irregularly distributed throughout the Gunflint Iron Formation, and range from 1 to 16 μm in diameter. The … See more Various predominant taphonomic models have been suggested as mechanisms for the exceptional preservation of the Gunflint Chert See more WebThe Gunflint Formation was deposited on an Archean basement at the southwestern margin of the Superior Province (see Canadian Precambrian Shield).Occurrence of granular peloidal and oolitic iron formations or taconite (an iron-bearing, high-silica, chert-like rock) characterizes the Gunflint Formation.
Gunflint iron formation
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WebDec 29, 2024 · Near the Ontario—Minnesota boundary, the middle Precambrian sedimentary Gunflint Iron Formation has been contact metamorphosed by the Duluth Complex to the pyroxene hornfels facies. Three ... WebJan 1, 1976 · The gunflint stromatolites and living pertinent examples provide data for a biological-environmental approach to interpretation of stromatolite morphology. The …
WebThe Late Proterozoic Gunflint Formation comprises 100–160-m thick iron-rich chemical, clastic, and volcaniclastic sedimentary rocks extending for 175 km along the Gunflint Range from northeastern Minnesota, USA to the Thunder Bay area of Ontario, Canada. The iron formation is well dated at 1878 ± 1.3 Ma by U-Pb on zircons (Fralick et al. 2002).The … WebThe famous Gunflint fossils, from the Gunflint Iron Formation, Ontario 1, were the first well preserved and relatively diverse Precambrian microbiota to be described 2,3.
http://www.geology.wisc.edu/outcrop/00/00_pdfs/serendipity.pdf WebGunflint iron range as the Rove shale, which is usually recognized as a sepa-rate formation overlying the Gunflint formation. Petrography of the Chert The rocks of the lower algal hori-zon of the Gunflint formation are com-posed dominantly of dense black chert associated with subordinate amounts of gray, green, red, and white cherts. The
WebThe Gunflint Formation was deposited on an Archean basement at the southwestern margin of the Superior Province (see Canadian Precambrian Shield).Occurrence of …
WebAug 20, 2024 · Here, we report the widespread presence of solidified oil (pyrobitumen) in the iron formation of the 1.88 Ga Gunflint Formation, Ontario, Canada. Petrographic textures indicate at least two phases of oil migration, an early phase marked by pyrobitumen in granules and intergranular pores, synchronous with synsedimentary silica … pinty\\u0027s frozen turkey thawedWebBreccia containing large fragments of Gunflint Iron Formation. Hammer for scale is 16 inches long. Only the uppermost part of the layer at Gunflint Lake contains true … pinty\\u0027s gluten freeWebMay 10, 2024 · The approximate upper age limit of the Gunflint Formation is based on the U-Pb age of 1.87 Ga (Morey, 1969; Fralick et al.,2002) for the upper Gunflint Formation and the overlying Rove Formation. The Gunflint Formation is a 120 m thick succession of metasedimentary strata that includes siliciclastic, carbonate, chert, and iron formation ... pinty\\u0027s frozen turkeyWebThe Gunflint iron formation is part of a Late Precambrian sedimentary-volcanic series that overlies with major unconformity an ancient granite-greenstone pediment surface. Iron- … pinty\\u0027s gluten free chickenWebThe Biwabik Iron Formation, known to be more than 1.7 aeons old (ref. 5, p. 5), is generally considered to be the lateral and time equivalent of the roughly 1.9-aeon-old Gunflint Iron Formation in the Mesabi Range of northeastern M\4inne-sota. Being the major iron-producing formation of the region, it has been inten-sively studied (e.g., ref. 6). step by step search engine optimizationWebTwo new algal taxa are described from the approximately 2,000 m.y. old Gunflint Iron Formation, Ontario. Leptoteichos golubicii, n. gen. et sp., were relatively large (5-31 … pinty\u0027s gluten freeWebApr 17, 2024 · The 1.88 Ga Gunflint Formation in Ontario, Canada, has played a key role in the development of current models for the deposition of iron formations. The … step by step scale model tank chipping