Tidal deposits in the early Proterozoic basin of the Lake Superior region—The Palms and the Pokegama Formations: Evidence for subtidal-shelf deposition of Superior-type banded iron-formation

1983 ◽  
pp. 49-66 ◽  
Author(s):  
Richard W. Ojakangas
Keyword(s):  
Lake Superior ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Early Proterozoic ◽  
Tidal Deposits ◽  
Superior Type

A mixed seawater and hydrothermal origin of superior-type banded iron formation (BIF)-hosted Kouambo iron deposit, Palaeoproterozoic Nyong series, Southwestern Cameroon: Constraints from petrography and geochemistry

2017 ◽  
Vol 80 ◽  
pp. 860-875 ◽  
Author(s):  
Ganno Sylvestre ◽  
Njiosseu Tanko Evine Laure ◽  
Kouankap Nono Gus Djibril ◽  
Djoukouo Soh Arlette ◽  
Moudioh Cyriel ◽  
...  
Keyword(s):  
Iron Formation ◽  
Iron Deposit ◽  
Banded Iron Formation ◽  
Hydrothermal Origin ◽  
Superior Type

Palladium-bearing gold deposit hosted by Proterozoic lake superior-type iron-formation at the Caue iron mine, Itabira District, southern Sao Francisco Craton, Brazil; geologic and structural controls; reply

1995 ◽  
Vol 90 (8) ◽  
pp. 2372-2374
Author(s):  
Gema Ribeiro Olivo ◽  
Michel Gauthier ◽  
Marc Bardoux ◽  
Euripides Leao de Sa ◽  
Jose Teotonio F. Fonseca ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Lake Superior ◽  
Iron Formation ◽  
Structural Controls ◽  
Iron Mine ◽  
Superior Type

Beginnings of biospheric evolution and their biogeochemical consequences

Paleobiology ◽  
1976 ◽  
Vol 2 (4) ◽  
pp. 351-387 ◽  
Author(s):  
Preston Cloud
Keyword(s):  
Lake Superior ◽  
Large Diameter ◽  
Indirect Evidence ◽  
Iron Formation ◽  
Crustal Evolution ◽  
Confidence Limits ◽  
Sulfate Ion ◽  
Banded Iron Formation ◽  
Simple Diffusion ◽  
Primary Origin

The beginnings of biospheric evolution had far-reaching biogeochemical consequences for the related evolutions of atmosphere, hydrosphere, and lithosphere. Feedback to the sedimentary record from these several simultaneously interacting aspects of crustal evolution provides the evidence from which historical biogeology is reconstructed. The interpretation of that evidence, however, is beset with pitfalls. Both biogenicity and a primary origin need to be demonstrated, or confidence limits established for each supposed morphological and biochemical fossil. Relevance to biospheric or related evolutions must be critically evaluated for every geochemical and sedimentological anomaly.Indirect evidence suggests primitive, oxygen-generating autotrophy by ∼ 3.8 × 109 years ago (3.8 Gyr or gigayears), while free O2 first began to accumulate only ∼ 2 Gyr ago. Various reduced substances in the atmosphere and in solution functioned as oxygen sinks, keeping photolytic and biogenic O2 at levels tolerable by primitive anaerobic and microaerophilic procaryotes.The oldest demonstrably biogenic and certainly primary microstructures are procaryotes from ∼ or > 2 Gyr old strata around Lake Superior. Improved biologic O2 mediation, continued carbon segregation, and filling of O2 sinks initiated atmospheric O2 buildup, leading to an ozone screen ∼ or < 2 Gyr ago. Consequences were essential termination of banded iron formation, onset of red beds, and O2 shielding of anaerobic intracellular processes, heralding the eucaryotic cell.Probable eucaryotes appear in ∼ 1.3 Gyr old rocks in California as large unicells and large-diameter, branched, septate filaments. Likely consequences of eucaryotic evolution were increased atmospheric O2, increased carbonate and sulfate ion, and the rise of sexuality. Meiosis had definitely evolved > 0.7 Gyr ago and probably > 1.3 Gyr ago, perhaps simultaneously with the mitosing cell. Whatever the timing, it completed the evolution of the eucaryotic heredity mechanism and foreshadowed (given sufficient free O2) the differentiation of tissues, organs, and advanced forms of life—with all their potential for biogeochemical feedback to sedimentary, diagenetic, and metallogenic processes. The first Metazoa appeared ∼ 0.7 Gyr ago. Being dependent on simple diffusion for O2, they lacked exoskeletons. The latter appeared, perhaps 0.6 Gyr ago, when increasing O2 levels favored the emergence of more advanced respiratory systems.

scholarly journals Lake Superior-type iron-formation

1995 ◽  
Author(s):  
G A Gross
Keyword(s):  
Lake Superior ◽  
Iron Formation ◽  
Superior Type

Palladium-bearing gold deposit hosted by Proterozoic lake superior-type iron-formation at the Caue iron mine, Itabira District, southern Sao Francisco Craton, Brazil; geologic and structural controls

1995 ◽  
Vol 90 (1) ◽  
pp. 118-134 ◽  
Author(s):  
Gema Ribeiro Olivo ◽  
Michel Gauthier ◽  
Marc Bardoux ◽  
Euripedes Leao de Sa ◽  
Jose Teotonio F. Fonseca ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Lake Superior ◽  
Iron Formation ◽  
Structural Controls ◽  
Iron Mine ◽  
Superior Type
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