scholarly journals Preliminary Description of the Origin of a Sedimentary – Exhalative Ore Deposit, in Molango, Hidalgo Mexico

2018 ◽  
Author(s):  
Eduardo Cerecedo-Sáenz ◽  
Ventura Rodríguez-Lugo ◽  
Juan Hernández-Ávila ◽  
Demetrio Mendoza-Anaya ◽  
Ma. Isabel Reyes-Valderrama ◽  
...  
Keyword(s):  
Continental Crust ◽  
Rare Earths ◽  
Mineral Deposit ◽  
Base Metals ◽  
Sulfur Deficiency ◽  
Ore Deposit ◽  
Upper Continental Crust ◽  
Distribution Of Elements ◽  
Hydrothermal Remobilization ◽  
Preliminary Description

This work shows the preliminary description of the origin of a sedimentary - exhalative outcrop of Jurassic Lower Pliensbachian. The location of this deposit was achieved by applying an examination based in the identification of sedimentary transgressions of heterochronies ages and the identification of a Rift – type mega –structure. According with the methodology, it was carried out a study of the discordant relationships between two types of sediments: continental and marine. According the characterization, it was noted the existence of light rare earths, in values that show positive anomalies in comparison with the distribution of elements in upper continental crust according to the Clarke [1], reflecting so a felsic affinity of the mineral deposit. Also, positive anomalies of platinum and Pd, were determined with marginal contents of Au and Ag; and finally the base metals Zn, Pb and Cu were detected in low contents, which could be due to the presence of altered shale. According to the sedimentary lithology found, which was of siliciclastic type; to the exhalative roots observed during the fieldwork; the presence of quartz minerals such as biotite and muscovite; the presence of minerals of hydrothermal remobilization like chalcopyrite with some base metals, altered shale, as well as sulfur deficiency; this mineral reservoir could be defined as a SEDEX – type.

Chemical Characterization of a Mineral Deposit of Economic Interest

2015 ◽  
Vol 1766 ◽  
pp. 115-122
Author(s):  
E. Cerecedo ◽  
V. Rodríguez ◽  
P.D. Andrade ◽  
E. Salinas ◽  
J. Hernández ◽  
...  
Keyword(s):  
Precious Metals ◽  
Chemical Characterization ◽  
Mineral Deposit ◽  
Black Shales ◽  
Economic Interest ◽  
Base Metals ◽  
Rock Unit ◽  
Ore Deposit ◽  
Representative Samples

ABSTRACTChemical and structural characterization of four representative samples of an ore deposit located in the eastern of Hidalgo State was carried out. According with the results, it could be appreciate some areas showing silicified zones with abundant amounts of disseminated pyrites that are part of a rock unit from early Jurassic consisting in inter - bedded black shales and sandstones. Thus, the contents of base metal were greater than 30 ppm Zn and 9 ppm Cu. Chemical analysis of rock gave the following results; 82 ppm of Ba, 1.64 % Wt. Fe, 0.08 % Wt. Ti, 40.8 % Wt. Si, 20 ppm of Ce, 2.2 ppm Co, 30 ppm Cr, 2.7 ppm Cs, 0.9 ppm Er, 2.5 ppm Ga, 1.6 ppm Gd , 1.5 ppm Ge, 9 ppm La, 71 ppm Li, 104 ppm Mn, 10 ppm Nd , 17 ppm Rb, 2 ppm Se, 9 ppm Sr, 10 ppm Ta, 6 ppm Te, 28 ppm V, 9 ppm Y, and 0.7 ppm Yb, among others. Finally, the values found for precious metals, were; Au < 0.02 ppm, Pd <0.05 ppm, Pt <0.05 ppm. It was inferred that the low content of base metals in outcrop studied, are due to the alteration of the black shales. According to these results, we can consider a stratiform – type mineralization of Pb-Zn which could be prospective for SEDEX – Type deposit. By means of XRD, it was possible to identify; pyrite, chalcopyrite, pyrrhotite, and minor amounts of sphalerite and Co -Ni arsenide.

scholarly journals Paleofluids and Recent fluids in the upper continental crust: Results from the German Continental Deep Drilling Program (KTB)

1997 ◽  
Vol 102 (B8) ◽  
pp. 18233-18254 ◽  
Author(s):  
P. Möller ◽  
S. M. Weise ◽  
E. Althaus ◽  
W. Bach ◽  
H. J. Behr ◽  
...  
Keyword(s):  
Continental Crust ◽  
Deep Drilling ◽  
Upper Continental Crust ◽  
Continental Deep Drilling

scholarly journals The silicon isotope composition of the upper continental crust

2013 ◽  
Vol 109 ◽  
pp. 384-399 ◽  
Author(s):  
Paul S. Savage ◽  
R. Bastian Georg ◽  
Helen M. Williams ◽  
Alex N. Halliday
Keyword(s):  
Continental Crust ◽  
Isotope Composition ◽  
Silicon Isotope ◽  
Upper Continental Crust

scholarly journals The zirconium isotope composition of the mantle and upper continental crust through time

2021 ◽  
Author(s):  
Shengyu Tian ◽  
Frédéric Moynier ◽  
Edward Inglis ◽  
Roberta L. Rudnick ◽  
Fang Huang ◽  
...  
Keyword(s):  
Continental Crust ◽  
Isotope Composition ◽  
Upper Continental Crust

Lithium isotopic composition and concentration of the upper continental crust

2004 ◽  
Vol 68 (20) ◽  
pp. 4167-4178 ◽  
Author(s):  
F.-Z. Teng ◽  
W.F. McDonough ◽  
R.L. Rudnick ◽  
C. Dalpé ◽  
P.B. Tomascak ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Continental Crust ◽  
Upper Continental Crust

Metal Sources in the Proterozoic Vazante-Paracatu Sediment-Hosted Zn District, Brazil: Constraints from Pb Isotope Compositions of Meta-Siliciclastic Units

2021 ◽  
Author(s):  
Neil A Fernandes ◽  
Gema R. Olivo ◽  
Daniel Layton-Matthews ◽  
Alexandre Voinot ◽  
Donald Chipley ◽  
...  
Keyword(s):  
Continental Crust ◽  
Isotopic Signature ◽  
Pb Isotope ◽  
Metal Sources ◽  
Upper Continental Crust ◽  
Basement Rocks ◽  
Siliciclastic Rocks ◽  
Brasiliano Orogeny ◽  
Isotope System ◽  
Parallel Arrays

ABSTRACT Different types of sediment-hosted whole-rock Pb isotope (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) compositions were determined from phyllites, carbonaceous phyllites (&gt;1% TOC), and meta-litharenites belonging to the Serra do Garrote Formation, which is part of the Proterozoic Vazante Group, Brazil. Results were integrated with lithogeochemistry in order to identify the Pb isotopic signature of Zn enrichment (up to 0.24 wt.% Zn) associated with meta-siliciclastic-hosted sulfide mineralization that formed prior to the Brasiliano Orogeny (850 to 550 Ma) in order to (1) understand the nature of siliciclastic sediment sources, (2) identify possible metal sources in pre-orogenic meta-siliciclastic-hosted Zn mineralization, and (3) evaluate the genetic links between the Zn enrichment in the relatively reduced phyllite package, and different styles of syn-orogenic Zn ± Pb mineralization (hypogene Zn-silicate and Zn-Pb sulfide) in overlying dolomitic carbonates throughout the Vazante-Paracatu Zn District, Brazil. The whole-rock 206Pb/204Pb and 207Pb/204Pb isotope ratios of meta-siliciclastic rocks plot as positively sloping, sub-parallel arrays with radiogenic, upper continental crust compositions, which could represent a detrital contribution from at least two upper continental crust sources. However, the 206Pb/204Pb versus 207Pb/204Pb isotope system does not distinguish between Zn-enriched samples and un-mineralized samples. In the whole-rock 206Pb/204Pb–208Pb/204Pb plot, Zn-enriched samples form a flat trend of lower 208Pb/204Pb values (38.3 to 39.5) compared to the Zn-poor ones that follow common upper crustal trends. Zinc-enriched samples have low whole-rock Th/U values (&lt;4) and higher whole-rock U concentrations compared to unmineralized samples. These support the hypothesis that U (± Pb) was added by pre-orogenic metalliferous fluids, which were in turn derived from underlying Paleoproterozoic and Archean basement rocks. Due to U addition, the original whole-rock thorogenic and uranogenic Pb isotope systems were decoupled in mineralized samples. Pre-orogenic metalliferous fluids have similar present-day first-order characteristics, including: (1) relatively high U/Pb and (2) low Th/U values, when compared to galena in the major carbonate-hosted Zn ± Pb deposits (Vazante, Morro Agudo, Ambrosia, Fagundes) in the Vazante Group. These results support the hypothesis that Zn-rich layers and veins in mineralized carbonaceous phyllites could be linked to the same origins as carbonate-hosted mineral deposits throughout the Vazante Basin, but further data are warranted. We suggest that the tectonic evolution of the Vazante Basin saw multiple phases of Zn-rich mineralization over protracted time periods from around 1200 to 550 Ma.

Evidence for contemporaneous Deccan volcanic aerosol deposition preceding the K-Pg boundary at El Kef, Tunisia

2021 ◽  
Author(s):  
Steffanie Sillitoe-Kukas ◽  
Munir Humayun ◽  
Thierry Adatte ◽  
Gerta Keller
Keyword(s):  
Continental Crust ◽  
Aerosol Deposition ◽  
Emission Rates ◽  
Volcanic Aerosol ◽  
Deccan Volcanism ◽  
Volatile Element ◽  
Asteroid Impact ◽  
Upper Continental Crust ◽  
El Kef ◽  
Volcanic Aerosols

&lt;p&gt;The cause of the Cretaceous-Paleogene extinction remains debated between an asteroid impact and volcanism. Precise geochronology showed that the extinction coincided with a voluminous phase (Poladpur eruption) of Deccan volcanism (Schoene et al., 2019). Paleontological evidence indicates that microfossil diversity declined about 300,000 years before the K-Pg boundary, synchronous with the onset of Deccan volcanism (Keller et al. 2009). High concentrations of Ir in the K-Pg boundary supported the asteroid hypothesis but recent work indicates that siderophile accumulation at the K-Pg in El Kef is secondary (Humayun et al., this conf.). Here, we critically examine existing element data for the K-Pg boundary and examine new results at the El Kef site, Tunisia, for volcanogenic volatile element accumulation associated with the contemporaneous Deccan eruptions. In this study, we analyzed 60 elements by laser ablation ICP-MS in search of these volcanic aerosol enrichments in the K-Pg sediments at El Kef, Tunisia. A study of siderophile element distribution at global K-Pg sites found that the Ru/Ir ratio is sub-chondritic. Mixing of upper continental crust (Ru/Ir&gt; CI) with a chondritic impactor fails to explain this trend. Volcanic aerosol emissions for Ir are well known but there is less data available for Ru. Relative emission rates of Ru were found to be lower than those of Ir for the Kudryavy volcano (Yudovskaya et al., 2008), so a possible explanation of the sub-chondritic Ru/Ir ratio observed in global K-Pg sites involves deposition of volcanic aerosols in sediments. We also modeled the effect of adding volcanic aerosols to sediments approximated compositionally as upper continental crust (UCC) to find that Re, Cd, Os and Ir are the first elements to become enriched in sediments by volcanogenic aerosol deposition. Sediments from El Kef below the K-Pg boundary are enriched in both Re and Cd. On a plot of Cd vs. Re, the K-Pg sediment from El Kef falls on a mixing line between volcanic aerosol (Erta Ale volcano) and UCC. Sediment at 3 cm above the K-Pg boundary has little enrichment of either Cd or Re, interpreted here to indicate that this sediment was deposited in the interlude between the Poladpur and the Ambenali eruption phases of the Deccan. The availability of chemical proxies of volcanogenic aerosol deposition in sediments enables direct correlation between fossil evidence and the contemporaneous intensity of volcanic outgassing, the likely destroyer of life by the Deccan eruptions (Keller et al., 2020).&lt;/p&gt;

Atmospheric dispersed sedimentary matter over the Barents sea

2021 ◽  
pp. 127-142
Author(s):  
V.P. Shevchenko ◽  
◽  
L.P. Golobokova ◽  
S.M. Sakerin ◽  
A.P. Lisitzin ◽  
...  
Keyword(s):  
Continental Crust ◽  
Barents Sea ◽  
Chemical Elements ◽  
Ionic Composition ◽  
Anthropogenic Pollution ◽  
Insoluble Fraction ◽  
The Arctic ◽  
Noticeable Effect ◽  
The Barents Sea ◽  
Upper Continental Crust

The concentration and composition of aerosols in the atmosphere over the Barents Sea were studied. Earlier, the contribution of aerosols to the formation of the Arctic environment was underestimated. Our data indicated a noticeable effect of continental aerosol on the atmosphere of the Barents Sea. The relationship of the black carbon concentration and the type of air masses has been established. Its concentration increases hundreds of times in the atmosphere of the sea when continental air is removed. The ionic composition and the content of chemical elements in the insoluble fraction of aerosols of the air over the Barents Sea were studied. The content of most chemical elements (Na, Al, K, Ca, Sc, Fe, Co, Rb, Zr, Cs, Ba, REE, Hf, Ta, Th, U) in the insoluble fraction of aerosols was below the average values for the upper continental crust. The content of Cr, Cu, Zn, As, Se, Br, Ag, Sb, Au, Pb is significantly higher than their average for the upper continental crust, due to the influence of the anthroposphere. Probable sources of anthropogenic pollution of aerosols in the Arctic are discussed.

scholarly journals Metallogenic Evolution of the Mackenzie and Eastern Selwyn Mountains of Canada’s Northern Cordillera, Northwest Territories: A Compilation and Review

2013 ◽  
Vol 40 (1) ◽  
Author(s):  
Luke Ootes ◽  
Sarah A. Gleeson ◽  
Elizabeth Turner ◽  
Kirsten Rasmussen ◽  
Steve Gordey ◽  
...  
Keyword(s):  
Northwest Territories ◽  
Hanging Wall ◽  
Gold Deposits ◽  
Mineral Deposit ◽  
Iron Formation ◽  
Low Grade ◽  
Base Metals ◽  
Geologic History ◽  
Coal Deposits ◽  
Mackenzie Mountains

The Mackenzie and eastern Selwyn Mountains, Northwest Territories, Canada, are the northeast expression of the Cordilleran orogen and have a geologic history that spans the last one billion years. The region has undergone a diverse tectonic evolution, which is reflected in an equally diverse collection of mineral deposits and prospects. More than 300 of these deposits and prospects have been documented in this area of the Northwest Territories and here they are categorized into mineral deposit types and their mode of formation evaluated and highlighted. Stratiform/stratabound Cu-Ag occurrences are hosted in the Neoproterozoic Coates Lake Group, generally preserved in the hanging wall of the Cretaceous Plateau fault, and define a belt through the central part of the Mackenzie Mountains. Low-grade phosphatic stratiform iron (47.5% Fe) occurs as iron formation in the Neoproterozoic Rapitan Group in the very northwest of the Mackenzie Mountains. Sedimentary exhalative Zn-Pb (± Ba) deposits are preserved in Cambrian through Devonian strata of the Selwyn Basin in the eastern Selwyn Mountains. Numerous carbonate-hosted Zn-Pb (± base-metals) occurrences are located in the Paleozoic strata of the Mackenzie Platform in the Mackenzie Mountains. Cretaceous felsic-intermediate plutons, which occur throughout the eastern Selwyn Mountains, are associated with tungsten skarn (proximal to intrusions), base-metal skarn (distal from intrusions), rare metals, semi-precious tourmaline related to pegmatites, and vein-hosted emeralds. Other resources of potential interest include coal deposits, placer gold, and possible Carlin-type gold deposits that have recently been identified farther west in the Yukon.SOMMAIRELes monts Mackenzie et ceux de la chaîne orientale de Selwyn, dans les Territoires du Nord-Ouest, au Canada, sont l'expression au nord-est de l'orogène de la Cordillère, et leur histoire géologique s’étale sur le dernier milliard d’années. La région a été l’hôte d’une évolution tectonique diversifiée, et cela se reflète par une suite tout aussi diversifiée de gisements minéraux et d’indices prometteurs. Plus de 300 de ces dépôts et indices prometteurs ont été documentées dans cette région des Territoires du Nord-Ouest, et le présent article ils sont classés en types de gîtes minéraux, et l’attention est portée sur leur mode de formation. Les gisements de Cu-Ag stratiformes ou stratoïdes sont encaissés dans le Groupe néoprotérozoïque de Coates Lake, et ils sont généralement préservés dans l'éponte supérieure de la faille du plateau crétacé, et ils forment une bande qui traverse la partie centrale des monts Mackenzie. Le fer se retrouve dans des gisements phosphatées stratiformes à faible teneur (47,5% Fe) qui provient de formations de fer dans le Groupe néoprotérozoïque de Rapitan situé dans la pointe nord-ouest des monts Mackenzie. Des gisements sédimentaires exhalatifs de Zn-Pb (± Ba) sont préservés dans des strates cambriennes à dévoniennes du bassin de Selwyn dans la portion est des monts Selwyn. De nombreux indices de Zn-Pb (± métaux communs) dans des roches carbonatées des strates paléozoïques de la plate-forme de Mackenzie, des monts Mackenzie. Des plutons felsiques intermédiaires crétacés, qui pointent tout au long de la chaîne est de Selwyn, sont associées à des skarns de tungstène (proximaux), à des skarns de métaux communs (distaux), à des concentrations de métaux rares, de tourmaline semi-précieuses liés aux pegmatites, et à des émeraudes filoniennes. Parmi d’autres ressources d'intérêt, on retrouve des gisements de charbon, d'or alluvionnaire, et d’éventuels gisements d'or de type Carlin qui ont été découverts récemment plus à l'ouest au Yukon.

scholarly journals Tungsten-182 in the upper continental crust: Evidence from glacial diamictites

2018 ◽  
Vol 494 ◽  
pp. 144-152 ◽  
Author(s):  
A. Mundl ◽  
R.J. Walker ◽  
J.R. Reimink ◽  
R.L. Rudnick ◽  
R.M. Gaschnig
Keyword(s):  
Continental Crust ◽  
Upper Continental Crust
Sign in / Sign up

Export Citation Format

Share Document