Landslides triggered by earthquakes in the central Mississippi Valley, Tennessee and Kentucky

The pottery in the following sections is not considered to belong to the Alto Focus complex, but to occur with it at different points in the Davis site occupation by trade or other means. If the writer appears to vacillate over what is and what is not trade pottery here, it is due in part to the problem of separating what could have been produced at the site (as extreme variations of resident styles) from what probably was not (because of some distinctive attribute which would mark it as foreign). In certain cases of pronounced deviation, a foreign origin is obvious enough, particularly when the source areas are well known. But where the whole tradition is similar as in the clay-tempered pottery of the lower Mississippi Valley region, and a great range of decorative techniques was employed for long periods of time, the problem is not easy.

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10. In the Mississippi Valley (1863)

A History of the Negro Troops in the War of the Rebellion, 1861-1865 ◽

10.1515/9780823240425-012 ◽

2020 ◽

pp. 152-162

Keyword(s):

Mississippi Valley

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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 ◽

10.3390/geosciences11040172 ◽

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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