CHAPTER 7: Cretaceous-Tertiary formation of the Mississippi Embayment and Mississippi River

2009 ◽  
Keyword(s):  
Mississippi River ◽  
Mississippi Embayment

REMOTE SENSOR APPLICATIONS TO TECTONISM AND SEISMICITY IN THE NORTHERN PART OF THE MISSISSIPPI EMBAYMENT

Geophysics ◽  
1977 ◽  
Vol 42 (3) ◽  
pp. 542-548 ◽  
Author(s):  
Dennis W. O’Leary ◽  
Shirley L. Simpson
Keyword(s):  
Mississippi River ◽  
Magnetic Anomalies ◽  
Landsat Images ◽  
Opening Wedge ◽  
Mississippi Embayment ◽  
Sensor Applications ◽  
Tectonic Model ◽  
The North ◽  
Regional Tectonic ◽  
New Madrid

A comparative study of Landsat images, SLAR image strips, and Skylab photographs was made to help develop a regional tectonic model and to evaluate the seismic hazards of the northern part of the Mississippi embayment as far south as the Ouachita front. The geomorphic character and distribution of lineaments reflects the structure and tectonics of the area. The fairly consistent trends of northwest‐oriented lineaments suggest the influence of jointing, whereas the variable north‐ and northeast‐trending groups suggest a variety of influences including jointing, faulting, and surficial factors that control stream orientation. A number of northeast‐trending faults are relatively recent, or have significant surface displacements, as they disrupt slopes in equilibrium with drainage. Seismic and aeromagnetic data are available for part of the area. Well‐defined trends of epicenters near New Madrid conform to a pronounced lineament pattern along the Mississippi River. Over a small area near New Madrid, a trend analysis was made of the totals of length‐width ratios of magnetic anomalies grouped in 10-degree intervals. Anomaly trend distributions show some correlation with the azimuth frequency diagrams of lineaments in the embayment. These data suggest basement control along gradients of magnetic anomalies where they parallel mapped lineaments. The tectonic pattern of the area is generally revealed in the landscape, of which the lineaments seem to be a particularly important part. The Mississippi River flows along an axis of active subsidence, possibly actually controlled by tectonic events along the west edge of the embayment, including uplift of the Ozark dome. The tectonic evolution seems to be one of an episodically opening wedge, combining strike‐slip movement along the north and west side of the embayment and step‐faulting down to the east.

scholarly journals Detrital Zircon Provenance and Lithofacies Associations of Montmorillonitic Sands in the Maastrichtian Ripley Formation: Implications for Mississippi Embayment Paleodrainage Patterns and Paleogeography

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 80
Author(s):  
Jennifer N. Gifford ◽  
Elizabeth J. Vitale ◽  
Brian F. Platt ◽  
David H. Malone ◽  
Inoka H. Widanagamage
Keyword(s):  
Mississippi River ◽  
Detrital Zircon ◽  
Drainage System ◽  
Clay Mineralogy ◽  
Foreland Basin ◽  
Mississippi Embayment ◽  
Fluvial Systems ◽  
Source Regions ◽  
Cretaceous Volcanism ◽  
Appalachian Foreland

We provide new detrital zircon evidence to support a Maastrichtian age for the establishment of the present-day Mississippi River drainage system. Fieldwork conducted in Pontotoc County, Mississippi, targeted two sites containing montmorillonitic sand in the Maastrichtian Ripley Formation. U-Pb detrital zircon (DZ) ages from these sands (n = 649) ranged from Mesoarchean (~2870 Ma) to Pennsylvanian (~305 Ma) and contained ~91% Appalachian-derived grains, including Appalachian–Ouachita, Gondwanan Terranes, and Grenville source terranes. Other minor source regions include the Mid-Continent Granite–Rhyolite Province, Yavapai–Mazatzal, Trans-Hudson/Penokean, and Superior. This indicates that sediment sourced from the Appalachian Foreland Basin (with very minor input from a northern or northwestern source) was being routed through the Mississippi Embayment (MSE) in the Maastrichtian. We recognize six lithofacies in the field areas interpreted as barrier island to shelf environments. Statistically significant differences between DZ populations and clay mineralogy from both sites indicate that two distinct fluvial systems emptied into a shared back-barrier setting, which experienced volcanic ash input. The stratigraphic positions of the montmorillonitic sands suggest that these deposits represent some of the youngest Late Cretaceous volcanism in the MSE.

The Effect of Exogenous Fluoride on the Calcium PUMP, Ciliary Activity, and Shell Formation of the Fingernail Clam, Musculium Transversum

1982 ◽  
Vol 40 ◽  
pp. 58-59
Author(s):  
Anthony Paparo ◽  
Judy A. Murphy ◽  
Robert Dean
Keyword(s):  
Mississippi River ◽  
Calcium Pump ◽  
Bottom Fauna ◽  
Ciliary Activity ◽  
Shell Formation ◽  
Middle Reach ◽  
Shell Matrix ◽  
Fingernail Clams ◽  
Ca Carbonate

In the mid-1950's, fingernail clams virtually disappeared from a 100-mile section of the IL River, a tributary of the Mississippi River, due to unknown causes. A survey of the bottom fauna of the IL River in 1979, revealed that the clams were still absent from the middle reach of the River, where they had been abundant prior to the die-off in the 1950's. Some factor(s) in the River currently prevent the clams from recolonizing areas where they were formerly abundant. Recently, clams exposed to fluoride developed abnormal grooves in the shell matrix. Fluorides are known to be protoplasmic poisons removing essential body calcium by precipitation. Since the shell consists primarily of Ca carbonate, this investigation examines the possible role of fluoride on shell formation and the poisoning of the Ca pump which can directly inhibit lateral ciliary activity on the gill.

Sign in / Sign up

Export Citation Format

Share Document