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Articles 661 - 690 of 763

Full-Text Articles in Earth Sciences

Changes In Forest Soils Following Clearcutting Of Pine Forests In The Ouachita Mountains Of Arkansas, Harlan R. Stoin, Bajuri Bin Kadmin, Lyell F. Thompson Jan 1985

Changes In Forest Soils Following Clearcutting Of Pine Forests In The Ouachita Mountains Of Arkansas, Harlan R. Stoin, Bajuri Bin Kadmin, Lyell F. Thompson

Journal of the Arkansas Academy of Science

Soil characteristics of the mineral surface soil (0-6 cm) on three small watersheds in the Ouachita Mountains of Arkansas from which the pine forests have been clearcut, crushed, and burned for site preparation were studied for the first two years following clearcutting and compared to soils from adjacent uncut pine forest watersheds. Following clearcutting and burning, soil pH was generally higher than in uncut forest soils. The greatest pH differences occurred within several months of burning and generally decreased through the end of the second year. Soil organic matter content was lower immediately following clearcutting and burning and increased to …


Groundwater Quality And Mineral Deposits Relationships In The Ozark Mountains, Kenneth F. Steele Sep 1984

Groundwater Quality And Mineral Deposits Relationships In The Ozark Mountains, Kenneth F. Steele

Arkansas Water Resources Center Technical Reports

Ninety-nine groundwater sites were sampled in northern Arkansas in order to determine the effect of local manganese, phosphate, pyrite, lead-zinc and uranium mineralization on the groundwater chemistry. Most of this study (75 springs) was concentrated in the Batesville manganese district. Hydrogeochemical exploration for these types of manganese deposits appears possible with 44 percent of the springs within 2000 feet of mineralization having anomalous metal concentrations (especially manganese). Because only a few springs were sampled in the remaining areas, the results are not conclusive; however, only the pyrite and small lead-zinc deposit would appear worthy of additional investigation. None of the …


Implications Of Hydrocarbon And Helium Gas Analyses Of Springs From The Ouachita Mountains, Arkansas, Randel T. Cox, Kenneth F. Steele Jan 1984

Implications Of Hydrocarbon And Helium Gas Analyses Of Springs From The Ouachita Mountains, Arkansas, Randel T. Cox, Kenneth F. Steele

Journal of the Arkansas Academy of Science

One hundred and three ground water samples (predominantly springs) were analyzed for headspace light hydrocarbon gases and helium. Four of the formations (Arkansas Novaculite, Bigfork Chert, Stanley Shale, and Womble) having the highest mean methane values are the only Ouachita Mountain facies to produce petroleum or exhibit marginally commercial production. This observation suggests that the mean methane values are useful as an indication of the relative hydrocarbon content of these formations Anomalous helium values are generally associated with mapped faults.


Disposal Of Household Wastewater In Soils Of High Stone Content (1981-1983), E. M. Rutledge, C. R. Mote, D. T. Mitchell, M. S. Hirsch, M. D. Harper, H. D. Scott, C. L. Griffis Dec 1983

Disposal Of Household Wastewater In Soils Of High Stone Content (1981-1983), E. M. Rutledge, C. R. Mote, D. T. Mitchell, M. S. Hirsch, M. D. Harper, H. D. Scott, C. L. Griffis

Arkansas Water Resources Center Technical Reports

Four experimental filter fields were constructed with built-in monitoring equipment in Nixa soils. These soils contain many chert fragments and a fragipan about 60 cm below the soil surface. The fragipan restricts downward movement of water and is the designlimitingfeature. The four filter fields were: 1. A "standard" filter field, 76 cm deep. The bottom of the trench was in the fragipan. 2. A "modified standard" filter field, 30 cm deep. The bottom of the trench was above the fragipan. 3. A "modified pressure" filter field, 40 cm deep. The bottom of the trench was above the fragipan. In addition, …


Disposal Of Household Wastewater In Soils Of High Stone Content (1977-1980), E. M. Rutledge, C. R. Mote, M. S. Hirsh, H. D. Scott, D. T. Mitchell May 1983

Disposal Of Household Wastewater In Soils Of High Stone Content (1977-1980), E. M. Rutledge, C. R. Mote, M. S. Hirsh, H. D. Scott, D. T. Mitchell

Arkansas Water Resources Center Technical Reports

Two experimental septic tank filter fields were constructed with built-in monitoring equipment in Nixa soils. These soils contain many chert fragments and a fragipan about 60 cm deep which restricts downward water movement and is the design-limiting feature. The standard filter field (76 cm deep) was built into the fragipan and the modified standard filter field (30 cm deep) was placed above it. During 30 months' observation, the modified standard performed better than the standard filter field. Maximum rise of effluent in the standard and modified standard came within 11 and 19 cm of the soil surface, respectively. Performance of …


Early Pennsylvanian Conodont-Ammonoid Biostratigraphy And The Witts Springs Problem, North-Central Arkansas, Mary Ann Eccher, Daniel J. Murdaugh, Wildon D. Hawkins Jan 1983

Early Pennsylvanian Conodont-Ammonoid Biostratigraphy And The Witts Springs Problem, North-Central Arkansas, Mary Ann Eccher, Daniel J. Murdaugh, Wildon D. Hawkins

Journal of the Arkansas Academy of Science

The Witts Springs Formation was proposed as a lithostratigraphic unit in north-central Arkansas to include the interval from a horizon equivalent to the base of the Prairie Grove Member, Hale Formation to the top of the Bloyd Formation, of the type Morrowan Series, northwestern Arkansas. The top of the Witts Springs Formation was regarded as being unconformably succeeded by the middle Pennsylvanian Atoka Formation. Recent investigation of this unit in its type area has shown that the presumed Atokan Sandstone is actually a unit confined to the Bloyd Formation. Thus, the type section of the Witts Springs in Searcy County, …


Atrazine Degradation, Sorption And Bioconcentration In Water Systems, Duane C. Wolf, Ramon L. Jackson Aug 1982

Atrazine Degradation, Sorption And Bioconcentration In Water Systems, Duane C. Wolf, Ramon L. Jackson

Arkansas Water Resources Center Technical Reports

The herbicide atrazine is used extensively to control broadleaf and grass weeds in such crops as sorghum and corn. A small portion of the atrazine may be lost from the area of application by surface runoff and could enter a stream or lake. The objective of this study was to evaluate atrazine degradation, sorption, and bioconcentration in watersediment systems. The results indicated that sediments with lower pH values and higher organic matter levels adsorbed higher levels of atrazine than sediments with neutral pH values and lower organic matter levels. Microbial decomposition of the herbicide was slow under the conditions of …


Reconnaissance Of The Bedrock Aquifers And Groundwater Chemistry Of Crawford, Franklin, And Sebastian Counties, Arkansas, Samuel R. Rothermel, Wyndal M. Robison, Julie L. Wanslow, James R. Musgrove, Daryll Saulsberry, Albert E. Ogden Jan 1982

Reconnaissance Of The Bedrock Aquifers And Groundwater Chemistry Of Crawford, Franklin, And Sebastian Counties, Arkansas, Samuel R. Rothermel, Wyndal M. Robison, Julie L. Wanslow, James R. Musgrove, Daryll Saulsberry, Albert E. Ogden

Journal of the Arkansas Academy of Science

A ground water reconnaissance of Crawford, Franklin, and Sebastian counties was performed utilizing 122 wells having drillers' logs from bedrock aquifers. North of the Arkansas River, essentially all bedrock wells produce from the Atoka Formation. There are many low producing aquifers within the Atoka with a range in yield of 0.1 to 55 gpm, but having a median yield of only 2 gpm. Well depths range from 18 to 248 feet with a median of 122 feet. More water is generally obtained from the shale/siltstone aquifers than the sandstones due to more bedding-plane partings and more closely spaced fractures. Greater …


Preliminary Investigation Of Ground-Water Occurrence In The Atoka Formation Of Pope And Faulkner Counties, Arkansas, Wyndal M. Goodman, Albert E. Ogden Jan 1982

Preliminary Investigation Of Ground-Water Occurrence In The Atoka Formation Of Pope And Faulkner Counties, Arkansas, Wyndal M. Goodman, Albert E. Ogden

Journal of the Arkansas Academy of Science

One hundred and twelve wells having drillers' logs were studied in Pope and Faulkner counties. Sixty-six of the wells produced water from shales and siltstones of the Atoka Formation while 46 produced from interbedded Atoka sandstones. Drillers' estimated well yields ranged from 1 to 100 gpm, but the median yield was only 9 gpm. Well depths ranged from 30 to 337 feet with a median depth of 100 feet. Ground-water is usually obtained from a series of low-producing confined aquifers of low artesian pressure. Pressure head and production were shown, statistically (a = .01), to decrease with increasing well depth. …


Stratigraphy Of A Pennsylvanian Deltaic Sequence In Russellville, Arkansas, Christopher F. Moyer, Ken Fritsche Jan 1982

Stratigraphy Of A Pennsylvanian Deltaic Sequence In Russellville, Arkansas, Christopher F. Moyer, Ken Fritsche

Journal of the Arkansas Academy of Science

No abstract provided.


Reconnaissance Of Ground-Water Resources Of Stone And Independence Counties, Arkansas, Albert E. Ogden, James R. Musgrove, Lisa Milligan Jan 1982

Reconnaissance Of Ground-Water Resources Of Stone And Independence Counties, Arkansas, Albert E. Ogden, James R. Musgrove, Lisa Milligan

Journal of the Arkansas Academy of Science

No abstract provided.


Sr/Mg Ratios Of Pennsylvanian Limestone Units In Northwest Arkansas, George H. Wagner, Kenneth F. Steele, Doy L. Zachry Jan 1982

Sr/Mg Ratios Of Pennsylvanian Limestone Units In Northwest Arkansas, George H. Wagner, Kenneth F. Steele, Doy L. Zachry

Journal of the Arkansas Academy of Science

No abstract provided.


Comparing Three Water Quality Sampling Techniques For Measuring Non-Point Source Pollution In Forest Streams, R. Scott Beasley Mar 1981

Comparing Three Water Quality Sampling Techniques For Measuring Non-Point Source Pollution In Forest Streams, R. Scott Beasley

Arkansas Water Resources Center Technical Reports

Coshocton wheel samplers, ISCO pumping samplers, and single stage samplers were compared on each of three small (5-6 ha), forested watersheds in the Ouachita Mountains of central Arkansas. The objective of the comparisons was to evaluate the performance of each sampling method in providing reliable samples for measuring concentrations of total suspended solids (TSS). H-flumes and water level recorders provided stream discharge data; a network of recording and non-recording raingages provided preciptation measurements. Rainfall and storm discharges during the study period were unusually low. No samples were collected by the single stage samplers. They appear unsuited for use on small …


Geology For The Layman, James O. Staggs Feb 1981

Geology For The Layman, James O. Staggs

Annual of the Arkansas Natural Resources Law Institute

The first thing that an individual must thoroughly understand, is that geology is not an exact science. This may be strange for a geologist to say, but it is very similar to the profession of law in that any set of data may be and is usually interpreted differently by individual lawyers. We geologist start with some known facts (sometime geological), make assumptions, and then intrepret into the unknown. It is this interpretation that separates a successful geologist from a geologist. A successful oil finding geologist is a geologist that has developed this interpretation of geological facts into an art. …


Distribution Of Fenitized Crustal Xenoliths In Carbonatite Intrusions, West-Central Arkansas, John Sharp Jan 1981

Distribution Of Fenitized Crustal Xenoliths In Carbonatite Intrusions, West-Central Arkansas, John Sharp

Journal of the Arkansas Academy of Science

Crustal xenoliths from carbonatite intrusions in the Morrilton-Perryville Arkansas area display a variety of mineralogical and textural features that suggest that they are fragments of basement crystalline rock that has undergone sodic metasomatism resulting from their close proximity at depth to a carbonatite complex. With increasing degrees of fenitization, the leucocratic xenoliths range from granolite - syenite - analcite syenite, while the melanocratic xenoliths range from hornblende - biotite to aegerine-apatite. A definite increase in fenitization is observed from Morrilton in the north to Brazil Branch, 16.8 km to the south. Fenitized xenoliths from Brazil Branch are generally quite small …


Effects Of Changes In Surface Water Regime And/Or Land Use On The Vertical Distribution Of Water Available For Wetland Vegetation: Dynamic Model Of The Zone Of Aeration (Part 1 Of Completion Report For Project A-023-Ark), Robert N. Maccallum, R. A. Sims Jun 1980

Effects Of Changes In Surface Water Regime And/Or Land Use On The Vertical Distribution Of Water Available For Wetland Vegetation: Dynamic Model Of The Zone Of Aeration (Part 1 Of Completion Report For Project A-023-Ark), Robert N. Maccallum, R. A. Sims

Arkansas Water Resources Center Technical Reports

A mathematical model by Green, simulating one-dimensional vertical ground-water movement in unsaturated soils of the prairie region of Kansas, has been adapted for use in a wetlands environment typified by the wetlands forest of Eastern Arkansas. The model consists of two second-order, non-linear, partial differential equations and an algorithm for their numerical solution. The original model was extended to include functions for seasonal changes in transpiration and for drainage of excess precipitation. Before the addition of the two functions, the model reliability was limited to one growth season.


Chemistry Of The Spring Waters Of The Ouachita Mountains Excluding Hot Springs, Arkansas, George H. Wagner, Kenneth F. Steele Mar 1980

Chemistry Of The Spring Waters Of The Ouachita Mountains Excluding Hot Springs, Arkansas, George H. Wagner, Kenneth F. Steele

Arkansas Water Resources Center Technical Reports

This report is based on the chemical analysis of the waters from 93 springs and 9 wells. Springs, when free from metal plumbing, provide an uncontaminated source of the ground water and it was desired to obtain water uncontaminated with metals. A few wells were added to the list, usually because of their unique location in the sampling grid.


Relation Of Magnetic And Gravity Field Data To Selected Structural Elements Of The Central Portion Of The Arkoma Basin, John H. Mcbride Jan 1980

Relation Of Magnetic And Gravity Field Data To Selected Structural Elements Of The Central Portion Of The Arkoma Basin, John H. Mcbride

Journal of the Arkansas Academy of Science

In order to acquire a greater understanding of some of the major basement structural features characteristic of the Arkoma basin, magnetic and gravity data have been collected and analyzed for a selected area. Several anomalies exist and are found to be associated with faulting or major fracturing in the Precambrian basement. Modelling of source bodies based on magnetic and gravity values provides quantitative estimates of the depth as well as the geometry of basement structural geology.


Contamination Of Boone-St. Joe Limestone Groundwater By Septic Tanks And Chicken Houses, Gerald D. Cox, Albert E. Ogden, Gretta Slavik Jan 1980

Contamination Of Boone-St. Joe Limestone Groundwater By Septic Tanks And Chicken Houses, Gerald D. Cox, Albert E. Ogden, Gretta Slavik

Journal of the Arkansas Academy of Science

Eighty-one water samples were collected from wells in the Boone-St. Joe limestone aquifer of northwest Arkansas and analyzed for fecal coliform, fecal streptococcus, total coliform bacteria, chloride, phosphate, nitrate and sulfate to determine the degree of contamination. Forty-nine percent of the samples had fecal streptococcus counts greater than 1 colony per 100 ml, 68% had total coliform counts of 1 or more colonies per 100 ml, and 9% of the wells had fecal coliform counts of 1 or more colonies per 100 ml. Water from wells in Clarksville, Nixa, Noark, Tonti and Waben cherty silt loam soils showed from 83 …


Stratigraphic Relationships Of The Brentwood And Woolsey Members, Bloyd Formation (Type Morrowan), Northwest Arkansas, Thomas A. Mcgilvery, Charles E. Berlau Jan 1980

Stratigraphic Relationships Of The Brentwood And Woolsey Members, Bloyd Formation (Type Morrowan), Northwest Arkansas, Thomas A. Mcgilvery, Charles E. Berlau

Journal of the Arkansas Academy of Science

The Brentwood Member of the Bloyd Formation conformably overlies the Prairie Grove Member, Hale Formation in the type Morrowan succession of northwestern Arkansas. At its type locality, the Brentwood is separated from the underlying Prairie Grove Member by nearly 6 m of dark shale. Away from this area, the shale thins rapidly and the Hale-Bloyd boundary may be placed with difficulty. At some localities east of type section, the boundary is thought to be erosional rather than the more typical gradational contact. The Brentwood consists of discrete carbonate bodies separated by dark shales. The carbonates consist principally of open shelf …


Mercury Content Of Waters In The Midcontinent Region, Larry Barber Ii, Kenneth F. Steele Jan 1980

Mercury Content Of Waters In The Midcontinent Region, Larry Barber Ii, Kenneth F. Steele

Journal of the Arkansas Academy of Science

Two major areas of the midcontinent region were investigated for their aqueous mercury concentrations. Sixteen surface water and 17 ground water samples were collected in an eleven county area of N.W. Arkansas, S.W. Missouri and N.E. Oklahoma (Ozark area) and analyzed for total dissolved mercury by the flameless atomic absorption spectrophotometric method. The range (<0.2 to 0.8 ppb), the mean (0.4 ppb) and the median (0.4 ppb) are the same for both ground water and surface water. Values obtained for the Ozark area are slightly greater than those reported for surface water by others (about 0.1 ppb), but are well within the range reported for surface waters (0.1 to 17.0 ppb). The range for 102 ground water samples from the Ouachita Mountain area is <0.1 to 2.3 ppb, the mean 0.3 ppb and the median 0.1 ppb. Thus, the mercury values for this area are similar to those of the Ozark area except fora higher upper range. The mercury mineralization (cinnabar) in the southern part of the Ouachita Mountain area, in part, is the cause of the higher values. Only two samples (2.1 and 2.3 ppb), both from the Ouachita Mountain area, exceed the EPA drinking water limits of 2 ppb mercury in the western Arkansas region.


Preliminary Investigation Of The Ground-Water Resources Of Northern Searcy County, Arkansas, Wyndal M. Goodman, Albert E. Ogden Jan 1980

Preliminary Investigation Of The Ground-Water Resources Of Northern Searcy County, Arkansas, Wyndal M. Goodman, Albert E. Ogden

Journal of the Arkansas Academy of Science

Two aquifers are extensively used by residents of small communities and rural areas in northern Searcy County, Arkansas. The Mississippian Boone-St. Joe aquifer is generally the less productive and the shallower of the two. Ground-water yields for the Boone-St. Joe range from 0.5 to 75 gpm with a median yield of 5 and a mean of 9.8 gpm. Well depths range from 100 to 754 feet with a median depth of 350 feet and a mean of 360 feet. Confined conditions are indicated by the greater depths, whereas the Boone-St. Joe aquifer is unconfined when exposed at the surface. Underlying …


Preliminary Investigation Of The Ground-Water Resources Of Baxter, Fulton, Izard And Sharp Counties, Arkansas, Mike Liebelt, Gerald Lundy, Albert E. Ogden Jan 1980

Preliminary Investigation Of The Ground-Water Resources Of Baxter, Fulton, Izard And Sharp Counties, Arkansas, Mike Liebelt, Gerald Lundy, Albert E. Ogden

Journal of the Arkansas Academy of Science

One hundred and seventy-seven drillers' well reports were used to investigate the groundwater resources of Baxter, Fulton, Izard, and Sharp counties. The most widely utilized aquifer zone is composed of the Cotter and Jefferson City dolomites. The well depths range from 30 to 740 ft. with a mean and median of 264 and 225 ft., respectively. The drillers' yield estimates range from 1 to 50 gpm with a mean of 12.0 gpm and a median of 10 gpm. The piezometric surface has an average hydraulic gradient of 9 ft./mile with groundwater discharge occurring along the Spring and White Rivers. Overlying …


Hydrogeologic And Geochemical Investigation Of The Boone-St. Joe Limestone Aquifer In Benton County, Arkansas, Albert E. Ogden Oct 1979

Hydrogeologic And Geochemical Investigation Of The Boone-St. Joe Limestone Aquifer In Benton County, Arkansas, Albert E. Ogden

Arkansas Water Resources Center Technical Reports

The Boone-St. Joe limestone aquifer is an important unconfined aquifer for rural residents of Benton County, Arkansas. Pumping tests indicate a large range in production capability of the aquifer. The coefficient of transmissibility and specific capacity range from 24.8 to 24640 gpd/ft and 0.03 to 30 gpm/ft, respectively. No statistical relationship at a = 0.10 was found between each of these parameters and photo-lineament proximity. Drillers' estimated well yield (gpm) also showed no relationship to photo-lineament proximity. It is therefore concluded that choosing well sites along photo-lineaments for higher production is not as reliable for karstified carbonate aquifers such as …


Preliminary Investigation Of Rural-Use Aquifers Of Boone, Carroll, And Madison Counties, Arkansas, Albert E. Ogden, Nancy L. Taylor, Steve D. Thompson Jan 1979

Preliminary Investigation Of Rural-Use Aquifers Of Boone, Carroll, And Madison Counties, Arkansas, Albert E. Ogden, Nancy L. Taylor, Steve D. Thompson

Journal of the Arkansas Academy of Science

Approximately 500 water wells having driller's lithologic logs were plottedin Boone, Carroll, and Madison Counties, Arkansas. Three aquifers were found to be used by the rural residents and smaller communities. The most shallow of these is the Mississippian Boone-St. Joe aquifer. This aquifer is generally the least productive having a range of .25 to 60 gpm but a median productivity of only 5 gpm. Well depths for the Boone-St. Joe range from 46 to 464 ft. and have a median depth of 225 ft. The Boone-St. Joe aquifer is unconfined to semi-confined and yields sufficient quantities of water only when …


Lithostratigraphy Of The Cane Hill Member Of The Hale Formation (Type Morrowan), Northwest Arkansas, Robert T. Liner Jan 1979

Lithostratigraphy Of The Cane Hill Member Of The Hale Formation (Type Morrowan), Northwest Arkansas, Robert T. Liner

Journal of the Arkansas Academy of Science

The Hale Formation (lower Morrowan Series) is a sequence of sandstones and shales divided into the Cane Hill(lower) and Prairie Grove Members. In Washington County, Arkansas, the type Cane Hill consists predominantly of interbedded fine-grained, noncalcareous sandstones and silty shales often with a pebble conglomerate at its base. The member rests unconformably on Chesterian Strata of either the Pitkin Formation or underlying Fayetteville Formation, and it is unconformably overlain by the Prairie Grove Member. In Washington County, the Cane Hill exhibits a slight thickening trend to the south and east. Interpretation of sedimentary structures indicates that the Cane Hill was …


Hydrogeologic Investigation Of A Landfill Site In Washington County, Arkansas, Albert E. Ogden, Carlos J. Quintana Jan 1979

Hydrogeologic Investigation Of A Landfill Site In Washington County, Arkansas, Albert E. Ogden, Carlos J. Quintana

Journal of the Arkansas Academy of Science

A proposed landfill site near Wheeler, Washington Co., Arkansas, was investigated for its hydrogeologic suitability. The site is located on the highly fractured, cavernous, and cherty Boone Ls. The site is a small upland valley 4500 ft. north of Clear Creek. The valley containing the proposed site is a karst dry valley in which precipitation rapidly infiltrates, recharging the water table and local springs. The water table around the site was mapped to determine the hydraulic gradient and direction of ground-water movement. The water table slopes in a SE direction from the landfill towards Clear Creek with a steep hydraulic …


Final Report Buffalo National River Ecosystems Part Iv, R. E. Babcock, E. E. Dale, R. L. Meyer, D. G. Parker, E. G. Smith, M. D. Springer Jan 1978

Final Report Buffalo National River Ecosystems Part Iv, R. E. Babcock, E. E. Dale, R. L. Meyer, D. G. Parker, E. G. Smith, M. D. Springer

Arkansas Water Resources Center Technical Reports

Sampling point locations and analytical procedures remained unchanged from those outlined in previous Buffalo National River Ecosystem reports. The only significant change in analytical procedures was a reversion to the glass fiber filter method for collection and extraction of samples for chlorophyll analysis. This change was neeessitated by a need for filtering a larger volume to obtain enough chlorophyll for an accurate measurement. Samples were collected monthly from April 9 through December 30. No samples were taken in January or February due to the extremely uncertain traveling conditions caused by the frequent snows. Prior research indicates that the December 30 …


An Evaluation Of The Effects Of Dredging Within The Arkansas River Navigation System - Volume I - Introduction, Summary And Conclusions, And Recommendations, Arkansas Water Resources Research Center Jan 1978

An Evaluation Of The Effects Of Dredging Within The Arkansas River Navigation System - Volume I - Introduction, Summary And Conclusions, And Recommendations, Arkansas Water Resources Research Center

Arkansas Water Resources Center Technical Reports

The foundation for the development of the Arkansas River was laid with the authorization of many upstream reservoirs in the comprehensive River and Harbor Act of 1946 signed by President Truman. Subsequent authorizations were forthcoming and work began on many of the bank stabilization facilities in 1950 and on the major structures in 1957. The current McClellan-Kerr Arkansas River Navigation System was substantially completed in 1972. The authorized multiple-purpose plan for the Arkansas River and tributaries provided for the construction of coordinated developments in the interests of navigation, hydroelectric power, flood control, bank stabilization, and related benefits including recreation and …


Structural Geology Of The Brentwood-St. Paul Area, Northwest Arkansas, Mikel R. Shinn Jan 1978

Structural Geology Of The Brentwood-St. Paul Area, Northwest Arkansas, Mikel R. Shinn

Journal of the Arkansas Academy of Science

Photogeologic and field mapping of a 530 mi² area in southeastern Washington and southern Madison Counties, Arkansas, indicates that post-Atoka structural deformation occurred primarily through differential uplift of basement fault blocks. Northeast and east trending basement faults and fracture systems are present. Northeast trending features are related to the major fracture systems of the stable continental interior. They were initiated by shearing during Pre-Cambrian time and have subsequently acted as crustal zones of weakness along which mostly vertical movement has occurred. East trending basement faults may have originally developed as a result of tension between the stable Ozark uplift and …