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.

Reduction to the pole of the North American magnetic anomalies

Geophysics ◽  
1990 ◽  
Vol 55 (2) ◽  
pp. 218-225 ◽  
Author(s):  
J. Arkani‐Hamed ◽  
W. E. S. Urquhart
Keyword(s):  
North America ◽  
Gravity Anomalies ◽  
Magnetic Anomalies ◽  
Gravity Gradient ◽  
Plate Boundaries ◽  
Gravity Gradients ◽  
The North ◽  
Vertical Gravity Gradient ◽  
Regional Tectonic ◽  
Vertical Gravity

Magnetic anomalies of North America are reduced to the pole using a generalized technique which takes into account the variations in the directions of the core field and the magnetization of the crust over North America. The reduced‐to‐the‐pole magnetic anomalies show good correlations with a number of regional tectonic features, such as the Mid‐Continental rift and the collision zones along plate boundaries, which are also apparent in the vertical gravity gradient map of North America. The magnetic anomalies do not, however, show consistent correlation with the vertical gravity gradients, suggesting that magnetic and gravity anomalies do not necessarily arise from common sources.

Is the Cape Smith Belt (northern Quebec) a klippe?

1985 ◽  
Vol 22 (9) ◽  
pp. 1361-1369 ◽  
Author(s):  
Paul F. Hoffman
Keyword(s):  
Shear Zone ◽  
Granulite Facies ◽  
Magnetic Anomalies ◽  
Ductile Shear Zone ◽  
Tectonic Model ◽  
The North ◽  
Thrust Sheets ◽  
Ductile Shear ◽  
Normal Sense ◽  
East West

The Cape Smith Belt is one of the most interesting and controversial of the proposed geosutures in the Canadian Shield. A new tectonic model is presented in which the mafic–ultramafic thrust sheets of the belt constitute a klippe, 20 000 km2 in area, separated from underlying basement of Superior Province and its thin autochthonous cover by a continuous décollement exposed along the north margin and the plunging eastern end of the belt. Thrusting is directed southward, and the entire stack is folded into a regional antiform (north of the belt) and synform (the belt itself). It is proposed that the décollement is rooted 30–90 km north of the belt, in a zone paralleling Sugluk Inlet, across which there is a major positive deflection in the Bouguer gravity field, an abrupt switch from broad north–south to narrow east–west magnetic anomalies, and a change in metamorphic grade from amphibolite to granulite facies from south to north. In the model, this zone is a north-dipping ductile shear zone juxtaposing crusts of two collided continents. Accordingly, granulite north of the zone represents lower crust of the overriding plate, whereas granulite between the zone and the klippe occurs in antiformal culminations in the underriding plate. One test of the model is that the south-dipping shear zone observed at the north margin of the belt should have a normal sense of slip. Another is that north-dipping banded gneiss at Sugluk Inlet should mark a ductile shear zone, also having a south-directed sense of overthrusting. A structural profile of the belt and its relation to basement can best be worked out by down-plunge projection of the eastern end of the belt.

scholarly journals Burial-deformation History of Folded Rocks Unraveled by Fracture Analysis, Stylolite Paleopiezometry and Vein Cement Geochemistry: A Case Study in the Cingoli Anticline (Umbria-Marche, Northern Apennines)

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 135
Author(s):  
Aurélie Labeur ◽  
Nicolas E. Beaudoin ◽  
Olivier Lacombe ◽  
Laurent Emmanuel ◽  
Lorenzo Petracchini ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Central Italy ◽  
Microstructural Analysis ◽  
Northern Apennines ◽  
Foreland Basins ◽  
Deformation History ◽  
The North ◽  
Regional Tectonic ◽  
History Of ◽  
Clumped Isotope

Unravelling the burial-deformation history of sedimentary rocks is prerequisite information to understand the regional tectonic, sedimentary, thermal, and fluid-flow evolution of foreland basins. We use a combination of microstructural analysis, stylolites paleopiezometry, and paleofluid geochemistry to reconstruct the burial-deformation history of the Meso-Cenozoic carbonate sequence of the Cingoli Anticline (Northern Apennines, central Italy). Four major sets of mesostructures were linked to the regional deformation sequence: (i) pre-folding foreland flexure/forebulge; (ii) fold-scale layer-parallel shortening under a N045 σ1; (iii) syn-folding curvature of which the variable trend between the north and the south of the anticline is consistent with the arcuate shape of the anticline; (iv) the late stage of fold tightening. The maximum depth experienced by the strata prior to contraction, up to 1850 m, was quantified by sedimentary stylolite paleopiezometry and projected on the reconstructed burial curve to assess the timing of the contraction. As isotope geochemistry points towards fluid precipitation at thermal equilibrium, the carbonate clumped isotope thermometry (Δ47) considered for each fracture set yields the absolute timing of the development and exhumation of the Cingoli Anticline: layer-parallel shortening occurred from ~6.3 to 5.8 Ma, followed by fold growth that lasted from ~5.8 to 3.9 Ma.

Timing of magmatism, foreland basin development, metamorphism and inversion in the Anglo-Brabant fold belt

1997 ◽  
Vol 134 (5) ◽  
pp. 607-616 ◽  
Author(s):  
G. VAN GROOTEL ◽  
J. VERNIERS ◽  
B. GEERKENS ◽  
D. LADURON ◽  
M. VERHAEREN ◽  
...  
Keyword(s):  
Subduction Zones ◽  
Foreland Basin ◽  
Fold Belt ◽  
East Anglia ◽  
Basin Inversion ◽  
Tectonic Model ◽  
The North ◽  
Basin Development ◽  
The North Sea ◽  
And Inversion

New data implying crustal activation of Eastern Avalonia along the Anglo-Brabant fold belt are presented. Late Ordovician subduction-related magmatism in East Anglia and the Brabant Massif, coupled with accelerated subsidence in the Anglia Basin and in the Brabant Massif during Silurian time, indicate a foreland basin development. Final collision resulted in folding, cleavage development and thrusting during the mid-Lochkovian to mid-Eifelian. In the southeast of the Anglo-Brabant fold belt, Acadian deformation produced basin inversion and the regional antiformal structure of the Brabant Massif. The uplift, inferred from the sedimentology, petrography and reworked palynomorphs in the Lower Devonian of the Dinant Synclinorium is confirmed by illite crystallinity studies. The tectonic model discussed implies the presence of two subduction zones in the eastern part of Eastern Avalonia, one along the Anglo-Brabant fold belt and another under the North Sea in the prolongation of the North German–Polish Caledonides.

scholarly journals 3D lithostratigraphic model of the Paleogene of the onshore part of the Moesian Platform (Northeast Bulgaria)

2018 ◽  
Vol 47 (1) ◽  
pp. 23-36
Author(s):  
Boris Valchev ◽  
Dimitar Sachkov ◽  
Sava Juranov
Keyword(s):  
Spatial Distribution ◽  
Sedimentary Rocks ◽  
Eastern Slope ◽  
The South ◽  
The North ◽  
Lithostratigraphic Units ◽  
Moesian Platform ◽  
Regional Tectonic ◽  
Model Database ◽  
The Individual

The Paleogene sedimentary rocks in the north-easternmost part of the territory of Bulgaria have been penetrated by numerous boreholes. In terms of regional tectonic zonation, the study area is a part of the onshore sector of the Moesian Platform, which partly includes the South Dobrogea Unit and the easternmost part of the North Bulgarian Dome with its eastern slope. The lithostratigraphy of the Paleogene successions consists of six formal units (the Komarevo, Beloslav, Dikilitash, Aladan, Avren, and Ruslar formations) and one informal unit (glauconitic marker). For compiling an overall conception of the regional aspects (lithology, thickness, spatial distribution, and relationships) of the individual lithostratigraphic units and for illustration of their spatial distribution, a 3D lithostratigraphic model based on reinterpretation of individual borehole sections has been created. The model database was compiled by integration of the original lithological data from 338 borehole sections.

scholarly journals Aufeis of the Indigirka river basin (Russia): the database from historical data and recent Landsat images

2018 ◽  
Author(s):  
Olga Makarieva ◽  
Andrey Shikhov ◽  
Nataliia Nesterova ◽  
Andrey Ostashov
Keyword(s):  
Interannual Variability ◽  
20Th Century ◽  
Historical Data ◽  
Topographic Maps ◽  
Landsat Images ◽  
North East ◽  
The North ◽  
Digital Database ◽  
Formation Conditions ◽  
Basin Area

Abstract. Detailed spatial geodatabase of aufeis in the Indigirka River, the basin area 305 000 km2, Russia was compiled from the Cadaster of aufeis of the North-East of the USSR published in 1958, topographic maps and Landsat images for 2013–2017. The aufeis area share varies from 0.26 to 1.15 % in different river sub-basins within the studied area. Digitized Cadaster (1958) contains the coordinates and characteristics of 897 aufeises with total area of 2064 km2. The Landsat-based identification of aufeises for 2013–2017 allowed the description of 1213 aufeises on a total area of 128 km2. The combined digital database of the aufeis is available at https://doi.pangaea.de/10.1594/PANGAEA.891036. The satellite-derived total area of aufeis is 1.6 times less than in the Cadaster (1958). At the same time, more than 600 aufeis identified by Landsat images analyses are missing in the Cadaster (1958). It implies that the aufeis formation conditions may have been changed between the mid-20th century and the present. About 60 % of total area presents 10 % of the largest aufeis. Most aufeis are located in the elevation band of 1100–1300 m. The interannual variability of the aufeis area was estimated by the example of the Bolshaya Momskaya naled (aufeis) and the group of large aufeis in the basin of the Syuryuktyakh River for the period of 2001–2016. The results of analysis indicate a tendency towards a decrease in the area of the Bolshaya Momskaya naled in recent years, at the same time the reduction in the aufeis area in the basin of the Syuryuktyakh River has not occurred.

Quaternary chronology and rock uplift recorded by marine terraces, Gaviota coast, Santa Barbara County, California, USA

2021 ◽  
Author(s):  
Daniel L. Morel ◽  
Kristin D. Morell ◽  
Edward A. Keller ◽  
Tammy M. Rittenour
Keyword(s):  
Southern California ◽  
Seismic Hazard Assessment ◽  
Fault System ◽  
The South ◽  
Tectonic Model ◽  
Transverse Ranges ◽  
Marine Terraces ◽  
Uplift Rates ◽  
Regional Tectonic ◽  
Source Models

The Transverse Ranges of southern California are a region of active transpression on the western margin of North America that hosts some of the world’s highest uplift rates at the Ventura anticline. Yet, the manner in which rock uplift rates change along strike from Ventura to the westernmost Transverse Ranges and the structures that may be responsible for this uplift remain unclear. Here, we quantified rock uplift rates within the westernmost 60 km of the Transverse Ranges by obtaining new age constraints from raised beach and shoreface deposits from marine terraces along the Gaviota coast. Twelve radiocarbon (seven sites) and eight luminescence (six sites) ages, ranging from ca. 50 to 40 k.y. B.P. and ca. 56 to 43 ka, respectively, consistently suggest that the first emergent terrace dates to marine isotope stage (MIS) 3, rather than MIS 5a as previously reported for the western Gaviota coast. These younger ages yield rock uplift rates between 0.8 ± 0.3 and 1.8 ± 0.4 m/k.y., i.e., over five times higher than previous estimates for this region. The spatial distribution of rock uplift rates and the abrupt along-strike changes in marine terrace elevations favor a regional tectonic model with a step-wise change in rock uplift across the south branch of the Santa Ynez fault. The south branch of the Santa Ynez fault appears to separate two regional tectonic blocks, characterized by rock uplift rates of ∼1.3−1.6 m/k.y. to the east and slightly lower rates to the west (∼0.8−1.4 m/k.y.). Our observations suggest that coastal rock uplift is primarily accommodated by deeply rooted far-field structures such as the offshore Pitas Point−North Channel fault system and the Santa Ynez fault, and that smaller through-going structures impart second-order controls and locally accommodate short-wavelength (<10-km-long strike length) deformation. These results imply that although the rates of rock uplift decline westward along strike, the westernmost portion of the western Transverse Ranges nonetheless accommodates relatively high (>1 m/k.y.) rock uplift rates at a significant distance (>50 km) from the rapidly uplifting (6−7 m/k.y.) Ventura anticline, and >100 km from the prominent restraining bend (“Big Bend”) in the San Andreas fault. The new constraints on the geometry of Quaternary-active structures and regional rates of fault-related deformation have implications for regional earthquake source models and seismic hazard assessment in the highly populated southern California coast region.

Borderland

Quarters ◽  
2019 ◽  
pp. 127-164
Author(s):  
John Gilbert McCurdy
Keyword(s):  
Native Americans ◽  
Mississippi River ◽  
North American ◽  
Unsolved Problem ◽  
Appalachian Mountains ◽  
The North ◽  
The Law ◽  
British Colonies

This chapter unearths quartering on the North American borderland where colonists and Native Americans struggled to live alongside one another, especially in the backcountry between the Appalachian Mountains and the Mississippi River. The Quartering Act included provisions to extend the law to places that were not organized British colonies, although this enforcement largely failed. Colonists and speculators advocated opening the backcountry to colonization as a means of paying for quartering troops, while Indian superintendents and British officers sought to leave the region to Native Americans. Ultimately, neither side prevailed; the borderland persisted and quartering in the backcountry remained an unsolved problem.

scholarly journals Study of soil erosion risks using remote sensing in Ouergha River watershed (Morocco)

2020 ◽  
Vol 150 ◽  
pp. 03012
Author(s):  
Imane Jaouda ◽  
Ahmed Akhssas ◽  
Latifa Ouadif ◽  
Lahcen Bahi ◽  
Jada Elkasri ◽  
...  
Keyword(s):  
Land Use ◽  
Vegetation Cover ◽  
Severe Drought ◽  
Human Intervention ◽  
Landsat Images ◽  
Erosion Rates ◽  
The North ◽  
Human Practices ◽  
Comparison Of The Results ◽  
Geological Formations

The watershed Ouergha River located in the north of Morocco suffer from vegetation cover degradation, this geographic entity is experiencing intense water erosion linked to the combination of several natural factors, such as the roughness and abundance of rainfall and the predominance of soft geological formations. Human intervention in this vulnerable environment accentuates its fragility by the clearing and degradation of the vegetation cover and the cultivation of land with a steep slope. This work aims to map the spatiotemporal evolution of this degradation by using the spot and Landsat images and the Radar image over a period from 1990 to 2014 data and aims to model its processes of erosion. In fact, the analysis of satellite data identified six main types of land use (eau, foret, reboisement…). It has also shown that the most degraded soils aren’t necessarily those with the greatest erosion rates over the past 15 years and that some soils that have developed well over time have become major exporters of sediments after clearing and cultivation. The comparison of the results of land use has highlighted the harmful impact of human practices on the acceleration of soil degradation. Human intervention, coupled to frequent and severe drought periods, remain the most important factors in the weakening and increasing vulnerability of soils to degradation. The results obtained by this approach made it possible to identify and monitor vulnerable areas at Ouergha watershed where interventions are needed to limit the processes of degradation of the soil and the natural environment.

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