Nemaha Anticline Research Articles

Restless Kansas: Evidence of Structural Development in the Flatlands

The Phanerozoic structural development of Kansas is recorded by the stratigraphic and sedimentological evidence. The early Paleozoic was relatively quiet, but a major change in the structural regimen took place in the late Paleozoic as a result of events in adjacent areas. Structural development was mainly by vertical differential movement along faults defining rigid Precambrian basement blocks as they adjusted to the stress. These movements are recorded in the changes of sediment thickness over the fault blocks. Concurrently, as the basement blocks adjusted, seismites were triggered by paleoearthquakes. By mapping the occurrence of seismites vertically and laterally, conclusions can be made on the frequency and intensity of the paleoquakes. The occurrence of seismites formed by paleoquakes seemingly diminish with time, but this may be a function of suitable conditions for their formation and preservation.Subsequent structural movement in the Mesozoic and Tertiary was mainly regional tilting, however, some convolute sedimentary structures and small intraformational faults in the Cretaceous indicate vertical movement was continuing. Paleoliquefaction features also have been reported in Holocene sediments in Edwards, Wabaunsee, and Woodson counties, Kansas. Historical recorded earthquakes and microseisms are evidence that the strain and structural movement is continuing today. Other than shallow man-made quakes, earthquake foci, in general seem to concentrate at two depths: 7.5 to 13.5km (Conrad discontinuity) and 35 to 50 km (Mohorovičić or Moho boundary). The major disturbances, for the most part, occur along the seismic active Nemaha Anticline from Nebraska to Oklahoma and the east-bounding Humboldt fault zone. From the available evidence, it is inferred that the structural development of Kansas is not and was not spectacular, but is and has been gradually continuous and intermittent.

Use of relational databases to evaluate regional petroleum accumulation, groundwater flow, and CO2 sequestration in Kansas

Large-scale relational databases and geographic information system tools are used to integrate temperature, pressure, and water geochemistry data from numerous wells to better understand regional-scale geothermal and hydrogeological regimes of the lower Paleozoic aquifer systems in the mid-continent and to evaluate their potential for geologic CO2 sequestration. The lower Paleozoic (Cambrian to Mississippian) aquifer systems in Kansas, Missouri, and Oklahoma comprise one of the largest regional-scale saline aquifer systems in North America. Understanding hydrologic conditions and processes of these regional-scale aquifer systems provides insight to the evolution of the various sedimentary basins, migration of hydrocarbons out of the Anadarko and Arkoma basins, and the distribution of Arbuckle petroleum reservoirs across Kansas and provides a basis to evaluate CO2 sequestration potential. The Cambrian and Ordovician stratigraphic units form a saline aquifer that is in hydrologic continuity with the freshwater recharge from the Ozark plateau and along the Nemaha anticline. The hydrologic continuity with areas of freshwater recharge provides an explanation for the apparent underpressure in the Arbuckle Group.

Origin and development of plains-type folds in the mid-continent (United States) during the late Paleozoic

Plains-type folds are local, subtle anticlines formed in the thin sedimentary package overlying a shallow, crystalline basement on the craton. They are small in areal extent (usually less than 1–3 km2 [0.4–1.2 mi2]), and their amplitude increases with depth (usually tens of meters), which is mainly the result of differential compaction of sediments (usually clastic units) over tilted, rigid, basement fault blocks. The development of these structural features by continuous but intermittent movement of the basement fault blocks in the late Paleozoic in the United States mid-continent is substantiated by a record of stratigraphic and sedimentological evidence.The recurrent structural movement, which reflects adjustment to external stresses, is expressed by the change in thickness of stratigraphic units over the crest of the fold compared to the flanks. By plotting the change in thickness for different stratigraphic units of anticlines on different fault blocks, it is possible to determine the timing of movement of the blocks that reflect structural adjustment. These readjustments are confirmed by sedimentological evidence, such as convolute, soft-sediment deformation features and small intraformational faults.The stratigraphic interval change in thickness for numerous structures in the Cherokee, Forest City, and Salina basins and on the Nemaha anticline of the mid-continent United States was determined and compared for location and timing of the adjustments. Most of the adjustment occurred during and after time of deposition of the Permian–Pennsylvanian clastic units, which, in turn, reflect tectonic disturbance in adjacent areas, and the largest amount of movement on the plains-type structures occurred on those nearest and semiparallel to major positive features, such as the Nemaha anticline.Depending on the time of origin and development of plains-type folds, they may control the entrapment and occurrence of oil and gas.

Abstract: Is the Mississippian of Kansas a Viable Petroleum Target After a Century of Exploration? 

The Mississippian rocks in Kansas have produced about 16% of the oil and 1 1 % of the gas of the total in the past 100 years. The Mississippian units are predominately uniform carbonates (mostly limestone), but are missing on the higher positive structures such as the Central Kansas Uplift and Nemaha Anticline. Production of petroleum is from both structural and stratigraphic traps. The present configuration of structures, formed near the end of the Mississippian when the North and South American plates collided, overprinted the previous structures and caused a change in the previous structural and sedimentary regimes in the region. An influx of upper Paleozoic clastics alternating rhythmically with carbonates signaled the onset of the Quachita Orogeny and major changes and provided the seal for the reservoirs. Mississippian units (up to 1,700 feet thick) include (from oldest to youngest): Kinderhookian, Osagean, Meramacian, and Chesteran; unconformably overlie the Siluro-Devonian or Ordovician units and are unconformably overlain by rocks of Pennsylvanian age - (from oldest to youngest) Morrowan, Atokan, or Desmoinesian. Since discovery of oil in the Mississippian in 19 16 in the Virgil field (Greenwood County), production from Mississippian rocks has accounted for slightly more than 13% of the state’s total oil and gas production. Although historically most of the Mississippian oil has been produced from the Salina and Sedgwick Basins, the increasing contribution of Mississippian oil to total production is primarily the result of exploration in the Hugoton Embayment in western Kansas. Information from 16,000 qualified wells was used to quality check formation data from 43,000 operator reported wells. Separating these new discoveries by date and comparing their spatial distribution to historical production provides a better understanding of emerging trends and new areas for exploration.

Geothermal field interpretation in south‐central Kansas for parts of the Nemaha Anticline and flanking Cherokee and Sedgwick basins

AbstractThe first assessment of temperature conditions in Kansas was made by geothermal gradient computations from temperature measurements in shallow boreholes, and these conditions are related to structural patterns, sedimentary cover and underlying basement properties. The area of south‐central Kansas was selected for detailed study of geothermal character in relation to the geology. The aim was to quantify the relations and to determine the relationship of different variables of the temperature field. Input parameters included geothermal variables of gradient and temperature, and structure and sediment thickness. Two approaches were used: (1) the numerical computation of theoretical temperature‐depth models based on conductive heat transfer, and (2) a map‐comparison technique based on algebraic methods. The temperature field information usable for the map comparison is different in response to different measurements (nonequilibrium BHTs and temperatures from logged measurements in equilibrium).Derived from modelled results (plotted isotherms on cross‐sections), a close relation between gradients and thermal conductivity of the sediments was confirmed. The most noticeable effect on the geothermal field, as noted quantitatively from the map‐comparison study, is the relation of thickness of outcropping Permo‐Pennsylvanian units because of their different thermal conductivity. The eastward increase of mean gradients is inversely related to the total sediment thickness, but this is mostly recognizable using the shallow temperature gradients. This dissimilarity gives additional evidence for a close link between gradients and thermal conductivity of the sediments in which the temperature measurements were made. The effect caused by the structure in deeper (older) units is not important and seems not to be significant, nor is the influence of the basement rock composition as indicated by the temperature modelling.

Depositional Environments of Wood Siding Formation and Onaga Shale (Pennsylvanian-Permian), Northeast Kansas: ABSTRACT

The eastern Kansas sedimentary deposits of the Wood Siding Formation and the Onaga Shale are recognized as products of Late Pennsylvanian-Early Permian cyclic sedimentation. Reconstruction of depositional events associated with the units is important in understanding cyclic sedimentation in the Mid-Continent. In Kansas, the Wood Siding Formation-Onaga Shale outcrop belt trends nearly parallel to the Nemaha anticline in an approximately northeast-southwest direction. Detailed field studies of 26 stratigraphic sections (nine measured and described in detail) in the northeastern part of this belt provide the basis for interpretation of the depositional environments of the two formations. Results of this study indicate that variations in water depth/distance from shore, controlled by late Paleozoic structural features and eustatic sea level changes, were the major factors controlling sedimentation. On the basis of lithologic and paleontologic characteristics, four fifth-order transgressive-regressive (T-R) units, with periodicities of 300,000 to 500,000 years, have been identified within the Wood Siding Formation and the Onaga Shale. At least five sixth-order T-R units, with periodicities of 50,000 to 130,000 years or less, have also been identified within the two formations. The boundaries between sixth-order T-R units are represented by thin, laterally persistent marine units or by climate change surfaces. Paleogeographic reconstructions,more » based on the correlation of sixth-order T-R units, provide strong evidence for a northeast-southwest-trending shoreline during Wood Siding-Onaga time. The most marine sedimentary rocks are in the southern part of the study area and contain a diverse marine fossil assemblage. Channel facies with pyritized and coalified plant fossils are more common in the northern part of the outcrop belt and suggest marshy to swampy depositional conditions.« less

Naturally Occurring Hydrogen Gas from a Borehole on the Western Flank of Nemaha Anticline in Kansas: ABSTRACT

Since August 1982, the CFA 1 Scott well in Sec. 20, T14S, R6E, Morris County, Kansas, located about 14 mi (23 km) south of Junction City, has yielded a gas composed of 50± 10% free hydrogen, 50± 10% nitrogen, and only traces of hydrocarbons. This analysis has been ascertained by gas chromatography and mass spectrography of samples taken over a period of 6 months. The reservoir rock is a Kinderhook sand from 2,176 to 2,196 ft (663 to 669 m) depth. The gas samples analyzed are accumulating in the head space above a fluid level (salt water) of 1,805 ft (550 m) from a bottom-hole depth of 2,197 ft (670 m). The Scott well is located on the western flank of the complexly faulted Nemaha anticline, updip from the central North American rift system and 30 mi (48 km) south of Riley County where serpentinized kimberlites occur. The geothermal gradient is 30°C/km (87° F/mi). Basement rock beneath the well is granite, probably overlying deeply buried magnetic rocks. Bulk composition of gas from the Scott well is similar to H2-rich gases issuing from hydrothermal vents at the 21°N site on the East Pacific Rise, and to certain gases occurring within the Zechstein strata of Poland. Mechanisms proposed by others to explain the origin of naturally occurring free hydrogen include: bacterial or inorganic decomposition of organic matter; bombardment of organic matter by radioactive decay products; high-temperature magmatic and volcanic processes; dissociation of H2O by low-temperature or metamorphic reactions involving sulfur species of the Fe+2 ^rarr Fe+3 redox half reaction (e.g., during serpentinization of ultramafic rocks), and mantle out-gassing of primordial reduced gases. For some wells, artificial production of H2 (e.g., oxidation of iron tools or pipe), also has been proposed to occur. Light, stable, isotope ratios (e.g., D/H, 18O/16O, and 15N/14N) may be distinctive suff ciently to rule out certain of the proposed H2-generating mechanisms. No single mechanism is responsible solely for generating this H2-rich gas from the Scott well; rather, a combination of fortuitous geologic and possibly biologic processes are contributing in various proportions to the production of the H2 and N2. Conceivably, the local geologic setting merely is circumstantial and unrelated to the genesis of the gases. However, in view of its spatial association with the central North American rift zone, a major geologic feature with similarity to the East Pacific Rise, the Kansas gas occurrence warrants additional study. End_of_Article - Last_Page 1324------------

Oil and Gas Developments in North Mid-Continent in 1977

Iowa's only test for oil in 1977 was dry. However, 25 injection/withdrawal wells were drilled into Ordovician and Cambrian rocks at a Louisa County natural gas storage facility. Kansas produced 57,496,021 bbl of crude oil, and 787,916,974 Mcf of natural gas, down 0.38% and 5.77% respectively from production in 1976. Drilling was off slightly (3,933 wells compared with 3,977 in 1976); 56.44% were successful. Natural gas exploration resulted in many Permian and Pennsylvanian producing wells along the Nemaha anticline. Niobrara gas is the target for leasing and drilling in northwestern Kansas, adjacent areas in Colorado, and northward across Nebraska. Sharon Springs is the first oil field in Wallace County. Cowley County, with 251 holes, had the most tests. Cunningham field, Pratt County, is being converted to a natural gas storage field. Missouri's 54 completions included many stratigraphic tests along the western border. Three dry holes in the Forest City basin in northwestern Missouri were drilled into Arbuckle and Precambrian rocks. With 424 holes, Nebraska's drilling was up 90 tests from the previous year. Hitchcock County had 46 new oil wells. Oil production in Nebraska was 5,968,452 bbl in 1977. No tests were drilled for oil or gas in Minnesota and Wisconsin.

Elk Creek, Nebraska, carbonatite: Strontium geochemistry

Subsurface carbonatite at Elk Creek, Nebraska has been recognized in drill core taken from a depth interval of 630 to at least 950 ft. The core in this interval consists of carbonated breccia and phlogopite-bearing carbonate rock. Total REE, P 2O 5 and Nb 2O 5 data are consistent with “average” values for carbonatite. 87Sr/ 86Sr ratios from the carbonate fraction range from 0.7030 to 0.7055 for fifteen of eighteen samples (total Sr varies from 300 to 3500 ppm; X= 1800ppm); the remaining three samples have 87Sr/ 86Sr and total Sr values of 0.7085 : 40 ppm; 0.7064 : 92 ppm; 0.7067 : 252 ppm; these samples may be mixed with sedimentary carbonate and/or contaminated by other non-carbonatite material. The Elk Creek carbonatite is of special interest because of its position with respect to tectonic elements in basement rocks. It occurs in the center of gravity and magnetic anomalies over the approximate axis of the Nemaha anticline and is apparently aligned with the Riley County, Kansas, carbonatite-bearing kimberlites. It is far removed from the E-W-trending “38th parallel” lineament along which occur numerous kimberlites and carbonatites.

Forest City Basin of Missouri, Kansas, Nebraska, and Iowa

The Forest City basin of Missouri, Kansas, Nebraska, and Iowa is the area in which the first oil and gas production west of the Mississippi River was found. Production near Paola, Kansas, followed within a few years of the birth of the oil industry at Titusville, Pennsylvania, in 1859 Initial movements of the Ozark uplift and the Chautauqua arch began in Late Ordovician time. Attendant subsidence in the north Kansas area formed an ancestral basin which was bisected later by the Nemaha anticline forming the Salina basin and an unnamed basin on the east. Post-Mississippian, pre-Atokan peneplanation of the entire area took place before renewed activity along the Nemaha anticline uplifted the area west of the anticline while downwarping east of the Nemaha scarp formed the Forest City basin. Thus it is defined as a Pennsylvanian basin. Movement along the Nemaha anticline may have begun during the late Early Ordovician but certainly it was mobile during Early Mississippian time and continued to be active intermittently until at least the early Permian. The Cherokee and Forest City basins were separated by a low arch until middle Cherokee time when the Forest City basin filled with sediments and the two basins linked across the Bourbon arch. Northeast-trending folds developed after Mississippian deposition whereas previous structural orientation was northwestward.

Sedgwick Basin: ABSTRACT

The Sedgwick basin is a moderate-size basinal structure, approximately 10-12,000 sq. mi. located in south-central Kansas. The basin is bounded on the east by the Nemaha anticline and on the west by the Pratt anticline. It is actually an embayment connected to a major Oklahoma structural basin. The northern boundary is poorly defined. It is separated from the Salina basin by lithologic changes within the rock section. These changes are the primary causes of a large number of producing zones. This paper deals with past and future prospects of the area with respect to these changes in lithologic types. End_of_Article - Last_Page 1561------------

Forest City Basin of Missouri, Kansas, Nebraska, and Iowa: ABSTRACT

The Forest City basin of Missouri, Kansas, Nebraska, and Iowa is the area of the first oil and gas production west of the Mississippi River. Production was found near Paola, Kansas, within a few years of the birth of the American oil industry at Titusville, Pennsylvania. Initial movements of the Ozark uplift and the Chautauqua arch began in Late Ordovician time. Attendant subsidence in the northern Kansas area formed an ancestral basin which was later bisected by the Nemaha anticline, forming the Salina basin on the west and an unnamed basin on the east. Post-Mississippian, Pre-Atokan peneplanation of the entire region took place before renewed activity along the Nemaha anticline uplifted the area west of the anticline while downwarping east of the Nemaha scarp formed the Forest City basin. Thus, it is defined as a Pennsylvanian-age basin. Movement along the Nemaha structure may have begun as early as pre-St. Peter time but certainly during Early Mississippian time and continued intermittently until at least the Early Permian. The Cherokee and Forest City basins were separated by a low arch until middle Cherokee time when the Forest City basin filled with sediments and the two basins joined across the Bourbon arch. Northeast-trending folds developed after Mississippian deposition, whereas previous structural orientation had been toward the northwest. End_of_Article - Last_Page 1564------------

History of earthquakes in Kansas*

Abstract Thirty-eight earthquakes which have affected Kansas are listed and described; 22 of these have occurred within the state's boundaries since 1867. There were 2 moderately strong ones—on April 24, 1867, and January 7, 1906. A frequency plot reveals that a moderately strong earthquake occurs in the state approximately every 40 to 45 years. A correlation of earthquakes with structural features in Kansas indicates that the Nemaha anticline is still tectonically active and that the earthquakes are probably occurring along a series of faults on the east side of the structure. Other positive structural elements such as the Cambridge arch and Central Kansas uplift are considered passive. The state, as a whole, is and probably always has been relatively stable.

Earthquake and Nemaha Anticline: GEOLOGICAL NOTES

Earthquake and Nemaha Anticline: GEOLOGICAL NOTES