The role of sulphur bacteria in the formation of the so-called sedimentary copper ores and pyritic ore bodies

1946 ◽  
Vol 41 (5) ◽  
pp. 517-538 ◽  
Author(s):  
Cornelius Schouten
Keyword(s):  
Ore Bodies ◽  
Sulphur Bacteria ◽  
Copper Ores

scholarly journals Structural Control on the Formation of Pb-Zn Deposits: An Example from the Pyrenean Axial Zone

Minerals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 489 ◽  
Author(s):  
Alexandre Cugerone ◽  
Emilien Oliot ◽  
Alain Chauvet ◽  
Jordi Gavaldà Bordes ◽  
Angèle Laurent ◽  
...  
Keyword(s):  
Structural Control ◽  
Predominant Role ◽  
Axial Zone ◽  
Regional Deformation ◽  
Structural Framework ◽  
Ore Bodies ◽  
Deformation Event ◽  
Key Parameter

Pb-Zn deposits and specifically Sedimentary-Exhalative (SEDEX) deposits are frequently found in deformed and/or metamorphosed geological terranes. Ore bodies structure is generally difficult to observe and its relationships to the regional structural framework is often lacking. In the Pyrenean Axial Zone (PAZ), the main Pb-Zn mineralizations are commonly considered as Ordovician SEDEX deposits in the literature. New structural field analyzes focusing on the relations between mineralization and regional structures allowed us to classify these Pb-Zn mineralizations into three types: (I) Type 1 corresponds to minor disseminated mineralization, probably syngenetic and from an exhalative source. (II) Type 2a is a stratabound mineralization, epigenetic and synchronous to the Variscan D1 regional deformation event and (III) Type 2b is a vein mineralization, epigenetic and synchronous to the late Variscan D2 regional deformation event. Structural control appears to be a key parameter in concentrating Pb-Zn in the PAZ, as mineralizations occur associated to fold hinges, cleavage, and/or faults. Here we show that the main exploited type 2a and type 2b Pb-Zn mineralizations are intimately controlled by Variscan tectonics. This study demonstrates the predominant role of structural study for unraveling the formation of Pb-Zn deposits especially in deformed/metamorphosed terranes.

Discovery of Yaguila Pb-Zn Polymetallic Deposit in Tibet: A Successful Case of Geochemical Prospecting

2012 ◽  
Vol 524-527 ◽  
pp. 278-284
Author(s):  
Xin Du ◽  
Chang Hai Yan ◽  
Jun Kui Chen ◽  
Xin Fa Li
Keyword(s):  
Research Area ◽  
Lower Permian ◽  
Geochemical Exploration ◽  
Polymetallic Deposit ◽  
Ore Bodies ◽  
Successful Case ◽  
Distribution Of Elements ◽  
Deposit Type ◽  
Iron Manganese

Yaguila Pb-Zn polymetallic deposit in Tibet is discovered through geochemical exploration techniques. The deposit is located in the eastern section of Longmala-Yaguila fault sag belt in the area of Nyainqentanglha Range. The ore bodies lie in the lithologic interface between tuffaceous sandstones and iron-manganese banded marbles in the Upper Carboniferous-Lower Permian Laigu formation. They occur in bedded and stratoid forms and are consistent with the attitude of strata. The paper reviews the process of discovering the deposit, and analyzes the important role of geochemical exploration in prospecting in the research area. It studies the geological characteristics of ore-forming, distribution of elements and features of anomalies, and finds out the Carboniferous- Permian is the main horizon Pb-Zn polymetallic anomalies form. The deposit type is submarine exhalative sedimentary-magmatic hydrothermal superimposition Pb-Zn polymetallic deposit. Furthermore, the paper also establishes a geology-geochemistry prospecting model for the research area and gives some suggestions to the further work, being of great significance in guiding geological prospecting in the research area.

Role of Fluid State Mobilization during Metamorphism of the Henderson Ore Bodies, Chibougamau, Quebec, Canada

1975 ◽  
Vol 12 (9) ◽  
pp. 1516-1523 ◽  
Author(s):  
Jayanta Guha ◽  
Jahak Koo
Keyword(s):  
Shear Zone ◽  
Regional Metamorphism ◽  
Volcanic Rocks ◽  
Low Grade ◽  
Fluid State ◽  
Ore Bodies ◽  
Calcite Veins ◽  
Intense Deformation ◽  
State Mobilization

The Henderson Cu-Au deposit occurs in discordant structures within the anorthosite zone of the Doré Lake Complex. The Doré Lake Complex is intruded into volcanic rocks of the Chibougamau greenstone belt on the southeastern side of the Superior Province. Massive to disseminated sulfide ores are associated with sericite, carbonate, chlorite and/or chloritoid schists within a large 'shear zone'. These ores show structural and textural evidence of intense deformation, recrystallization, and metamorphic mobilization.The deposit comprises not only sulfide schist ore with alternating sulfide and schist layers, but also 'hydrothermal' vein-type segregation ore. The latter is characterized by sulfide-bearing quartz-calcite veins that occur in the 'shear zone' and in the subsidiary fractures adjacent to it.The sulfide schist and vein types of ores can be attributed to partly solid state mobilization combined with fluid state mobilization from a pre-existing ore, and is an excellent example of extensive fluid state mobilization of sulfides under relatively low-grade regional metamorphism. It is suggested that fluid state mobilization can play an important role during the metamorphism of a pre-existing sulfide body, especially in the presence of differential stress accompanied with rupture. The deformational features of the ore are the important indication for syn- and/or pre-metamorphic origin of the ore.

The chemical evolution from older (323–318 Ma) towards younger highly evolved tin granites (315–314 Ma)—sources and metal enrichment in Variscan granites of the Western Erzgebirge (Central European Variscides, Germany)

2020 ◽  
Author(s):  
Marion Tichomirowa ◽  
Axel Gerdes ◽  
Manuel Lapp ◽  
Dietmar Leonhardt ◽  
Martin Whitehouse
Keyword(s):  
Granulite Facies ◽  
Source Rocks ◽  
Metamorphic Rocks ◽  
Control Factor ◽  
Basement Rocks ◽  
Ore Bodies ◽  
O Isotopes ◽  
Variscan Granites ◽  
Highly Evolved

<p>The sources and critical enrichment processes for granite related tin ores are still not well understood. The Erzgebirge represents one of the classical regions for tin mineralization. We investigated the four largest plutons from the Western Erzgebirge (Germany) for the geochemistry of bulk rocks and autocrystic zircons and relate this information to their intrusion ages. The source rocks of the Variscan granites were identified as high-grade metamorphic rocks based on the comparison of Hf-O isotope data on zircons, the abundance of xenocrystic zircon ages as well as Nd and Hf model ages. Among these rocks, restite is the most likely candidate for later Variscan melts.</p><p>In contrast to previously published suggestions (Romer and Kroner, 2015; Wolf et al., 2018), we can exclude a substantial role of intense sedimentary weathering as an important control factor for later Sn and W enrichment in granite related ores of the Western Erzgebirge due to the remarkable homogeneous Hf and low O isotopes in granitic zircons that are extremely distinct to all pre-Devonian basement rocks of Saxothuringia. We document a source enrichment from meta-sedimentary rocks (575 Ma) towards metamorphic rocks (340 Ma) were restites from granulite-facies melts are enriched 6–7 times in Sn compared to UCC (upper continental crust). These rocks are also enriched in K, but depleted in Na and Ca, contain abundant muscovite, and are fertile for later melting. Further enrichment of Sn and W occurred during multiple melt production of the older igneous granites (323–318 Ma) leading finally to a general enrichment of Sn (15 times compared to UCC) in the tin granites (315-314 Ma). Multiple melt production did not lead to a very strong enrichment of ore metals in the granites but is probably very important for a general enrichment of Sn and W in the thick granite-rich crust of the Erzgebirge. Efficient leaching by hydrothermal fluids led to a very strong enrichment (up to several orders) of Sn and W in the greisen ore bodies.</p><p> </p><p>References:</p><p>Romer, R.L.; Kroner, U. Sediment and weathering control on the distribution of Paleozoic magmatic tin-tungsten mineralization. Mineral. Depos. 2015, 50, 327–338, doi:10.1007/s00126-014-0540-5.</p><p>Wolf, M.; Romer, R.L.; Franz, L.; Lopez-Moro, F.J. Tin in granitic melts: The role of melting temperature and protolith composition. Lithos 2018, 310–311, 20–30.</p>

The Effects of Sulphide Generation in Waste Stabilization Ponds on Photosynthetic Populations and Effluent Quality

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1759-1768 ◽  
Author(s):  
S. R. Houghton ◽  
D. D. Mara
Keyword(s):  
Domestic Wastewater ◽  
Waste Stabilization Ponds ◽  
Effluent Quality ◽  
Stabilization Ponds ◽  
Waste Stabilization ◽  
Scale Models ◽  
Sulphur Bacteria ◽  
Sulphide Production

This study concerns the role of sulphide production in the reduction of algal populations and proliferation of purple sulphur bacteria in primary waste stabilization ponds, and the effect of such changes on effluent quality and hydrogen sulphide odour release. Full-scale ponds in Israel were compared to laboratory-scale models fed with domestic wastewater at various organic and sulphate loads. The phenomenon occurred in ponds whose organic loads were between those normally thought appropriate to facultative and anaerobic ponds. Algae of the genus Chlamydomonas were most tolerant of sulphide in ponds, confirming previous in vitro studies. Populations of both photosynthetic groups in the models were related to surface BOD5 loading rates and influent sulphate and sulphide concentrations. Purple sulphur bacteria were unable to prevent all odour release, so situations where they proliferate should be avoided by redesign. Shifts from algal to purple sulphur bacterial dominance caused by increased sulphide concentrations under constant loads were not observed to affect adversely effluent quality in terms of BOD5 and COD.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management

The power of norms to sway fused group members

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam
Keyword(s):  
Evolutionary Anthropology ◽  
Normative Systems ◽  
Violent Extremism ◽  
Identity Fusion ◽  
Group Members

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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