scholarly journals Cross sections of Lower Ordovician carbonate depositional lithofacies and Mississippi Valley-type zinc-and iron-sulfide mineralization in the Caufield district, east-central part of Harrison 1 degree by 2 degrees Quadrangle, Arkansas and Missouri

1992 ◽  
Keyword(s):  
Cross Sections ◽  
Iron Sulfide ◽  
Mississippi Valley ◽  
Sulfide Mineralization ◽  
East Central ◽  
Lower Ordovician ◽  
Mississippi Valley Type ◽  
Valley Type

Paleomagnetism and the Origin of Mississippi Valley-Type Ore Deposits

1974 ◽  
Vol 11 (2) ◽  
pp. 211-223 ◽  
Author(s):  
F. W. Beales ◽  
J. C. Carracedo ◽  
D. W. Strangway
Keyword(s):  
Natural Remanent Magnetization ◽  
Ore Deposits ◽  
The Other ◽  
Mississippi Valley ◽  
Ore Formation ◽  
Lower Ordovician ◽  
Southeast Missouri ◽  
Host Rocks ◽  
Mississippi Valley Type ◽  
Valley Type

Paleomagnetism can provide useful information about the stratigraphic relationships between the host rocks and the ore of some ore deposits.Four North American mines with stratabound ore deposits of Mississippi Valley type were sampled and the direction and intensity of the natural remanent magnetization (NRM) were measured. Two of the sites sampled (Newfoundland Zinc Co. property near Daniel's Harbour in western Newfoundland and the St. Joe Minerals Co., #8 Mine in southeast Missouri) had a weak, but measurable NRM in both host and ore rocks. This magnetization proved to be highly stable upon alternating field (AF) demagnetization. The other two mines (Magmont Mine, southeast Missouri, and Pine Point Mine, Northwest Territories, Canada) had intensities of magnetization too low to be measured after demagnetization.The pole positions computed for the ores and their corresponding hosts are identical within the statistical uncertainty, strongly suggesting that the ore and the host are, geologically speaking, of roughly the same age. This study gives two reliable pole positions, one for late lower Ordovician dolostone and sphalerite ore from Newfoundland of 26 °N, 126 °E, and the other for the upper Cambrian, based on the Bonneterre dolostone and galena ore from southeast Missouri of 35 °S, 170 °W.Within the present limitations of the method the results agree with published opinions concerning the age of the ore, i.e. that host rock and ore formation were relatively close in time. Therefore, when significant time differences occur between epigenetic ores and their host rocks, the method may be expected to define this. The method will become progressively more valuable as the apparent polar wandering curves for various continental areas become better defined.

scholarly journals Origin of the Moroccan Touissit-Bou Beker and Jbel Bou Dahar Supergene Non-Sulfide Biomineralization and its Relevance to Microbiological Activity, Late Miocene Uplift and Climate Changes

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 401
Author(s):  
Mohammed Bouabdellah ◽  
Wissale Boukirou ◽  
Adriana Potra ◽  
Erik Melchiorre ◽  
Hassan Bouzahzah ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Climatic Conditions ◽  
Current Data ◽  
Ore Deposits ◽  
Main Stage ◽  
Mississippi Valley ◽  
Sulfide Mineralization ◽  
Two Stages ◽  
Mississippi Valley Type ◽  
Valley Type

Through integration of Pb-Zn ± Cu non-sulfide mineralogy, texture, and stable isotope (C, O, S) geochemistry, the world-class Touissit- Bou Beker and Jbel Bou Dahar Mississippi Valley-type districts of the Moroccan Atlasic system have been investigated in order to gain insights into the origin and processes that contributed to the formation of the base metal non-sulfide mineralization. In both districts, direct replacement (“red calamine”) and wallrock replacement (“white calamine”) ores are observed. Based on the mineral assemblages, ore textures, and crosscutting relations, three distinct mineralizing stages are recognized. The earliest, pre-non-sulfide gossanous stage was a prerequisite for the following supergene stages and constituted the driving force that ultimately promoted the leaching of most base metals such as Zn and Cu and alkalis from their rock sources. The following two stages, referred to as the main supergene “red calamine” and late “white calamine” ore stages, generated the bulk of mineable “calamine” ores in the Touissit-Bou Beker and Jbel Bou Dahar districts. Stable isotope compositions (d13CV-PDB, d18OV-SMOW, d34SCDT) support a three-stage model whereby metals were released by supergene acidic fluids and then precipitated by bacteria and archaea-mediated metal-rich meteoric fluids due to a decrease in temperature and/or increase of fO2. Oxygen isotope thermometry indicates decreasing precipitation temperatures with advancing paragenetic sequence from 33° to 18 °C, with wet to semi-arid to arid climatic conditions. The close spatial relationships between coexisting sulfide and non-sulfide mineralization along with stable isotope constraints suggest that the oxidation of sulfides occurred concurrently after the main stage of the Alpine orogeny between 15 Ma and the present. More importantly, the current data show for the first time the involvement of biologically controlled activity as the major driving process that triggered both oxidation and deposition of supergene mineralization at Jbel Bou Dahar and Touissit-Bou Beker districts. Conclusions drawn from this study therefore have implications for supergene Mississippi Valley-type (MVT) -derived non-sulfide deposits worldwide and account for the prominent role of biological processes in the genesis of this category of ore deposits.

scholarly journals Radiogenic Pb Enrichment of Mississippi Valley-Type Metallic Ore Deposits, Southern Ozarks: Constraints Based on Geochemical Studies of Source Rocks and Their Diagenetic History

Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 172
Author(s):  
Jonathan Chick ◽  
Sydney E. McKim ◽  
Adriana Potra ◽  
Walter L. Manger ◽  
John R. Samuelsen
Keyword(s):  
Linear Trend ◽  
Ore Deposits ◽  
Source Rocks ◽  
Mississippi Valley ◽  
Isotopic Signatures ◽  
Boone Formation ◽  
Tripolitic Chert ◽  
Geochemical Studies ◽  
Mississippi Valley Type ◽  
Valley Type

Southern Ozark Mississippi Valley-type ores are enriched in radiogenic Pb, with isotopic signatures suggesting that metals were supplied by two end-member components. While the less radiogenic component appears to be derived from various shale and sandstone units, the source of the more radiogenic component has not yet been identified. Analyses of cherts from the Early Ordovician Cotter Dolomite and tripolitic chert from the Early Mississippian Boone Formation contain highly radiogenic Pb, with isotopic ratios comparable to those of ores. However, most samples have lower 208Pb/204Pb and 207Pb/204Pb for a given 206Pb/204Pb compared to ores. These relationships demonstrate that the enriched Pb isotopic values of the ore array cannot be related to the host and regional lithologies sampled, suggesting that the source of high ratios may lay further afield. The slope of the linear trend defined by the Pb isotope ratios of ores corresponds to an age of about 1.19 Ga. Therefore, an alternative for the linear array is the involvement of Precambrian basement in supplying ore Pb. Rare earth element patterns show that diagenetic processes involving the action of groundwater and hydrothermal fluids affected the sampled lithologies to various degrees, with Cotter Dolomite having experienced the highest degree of alteration.

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