Current Research in Earth Sciences

In this report I briefly outline the importance of and difficulties involved in estimating aquifer recharge and compare reported recharge estimates for the Great Bend Prairie aquifer of central Kansas and associated alluvial-valley aquifers of the Pawnee River and Walnut Creek. Results from 20 studies are reported, including ongoing recharge-related projects. These studies were conducted by three different state agencies, a federal agency, a Kansas University department, and a private consulting firm. The recharge estimates are classified into site-specific, countywide, subregional, and regional estimates. Estimates are consistent among all four spatial scales. The average of all estimates is approximately 2 in./yr (50 mm/yr). with an average recharge range of 1.7-2.5 in./yr (43-64 mm/yr).

Marios Sophocleous

Comparative Review and Synthesis of Ground-Water Recharge Estimates for the Great Bend Prairie Aquifer of Kansas

堪萨斯州大本德草原含水层地下水补给估算的比较回顾与综合

Significant quantities of mobile oil remain in Pennsylvanian reservoirsin the midcontinent region of the United States. To recover this oil efficiently, we mustunderstand the factors that control heterogeneity in these complex reservoirs. One wayto accomplish this is to evaluate reservoir-quality carbonate units that occur in both theoutcrop and the shallow subsurface as analogues to equivalent producing zones. Insoutheastern Kansas the lower Missourian Bethany Falls and Mound Valley limestonescontain oolitic grainstones similar to coeval productive lithofacies that occur in thedeeper subsurface to the west. Depositional sequence analysis of these grainstone-bearing units suggests that (1) at least two cycles of relative sea-level change led to thedeposition of discrete oolitic grainstones that are separated by subaerial exposuresurfaces, with these surfaces strongly influencing the vertical distribution of porosity,and (2) the character and distribution of reservoir-scale grainstone buildups werestrongly controlled by preexisting depositional topography.

John A. French

W. Lynn Watney

Stratigraphy and Depositional Setting of the Lower Missourian (Pennsylvanian) Bethany Falls and Mound Valley Limestones, Analogues for Age-Equivalent Ooid-Grainstone Reservoirs, Kansas

堪萨斯州下密苏里统（宾夕法尼亚系）贝萨尼瀑布和芒德谷石灰岩的地层与沉积环境，与同期鲕粒-砂屑岩储层类比

A series of wells have been drilled up to a depth of 3,444 m (113,000 ft) into the midcontinent rift system (MRS) in northeastern Kansas. The age of a gabbro sill in the upper portion of the Precambrian rocks was determined to be 1,097.5 ± 3 Ma, and the magnetic polarity of the gabbro correlated to the lower Keweenawan rocks in the northern MRS (Van Schmus et al., 1990). The rocks below 2,259 m (7,411 ft) in the deepest well [Poersch no. 1, total depth 3,435 m (11,270 ft)] consist mostly of arkoses with subordinate amounts of shale, siltstone, and basalt. The rocks above 2,265 m (7,431 ft) in the Poersch well consist of basalt with minor siltstone, arkose, gabbro, and felsite. A proposed high-angle reverse fault could have juxtaposed the upper igneous rocks over the lower sedimentary rocks to produce a reversed stratigraphy. This would make the development of the southern MRS similar to that of the northern MRS. Thus, in the initial extensional phase of the MRS, broad subsidence coincided with abundant volcanism and little sediment production. Grabens formed in the later stages of rift development and were filled with abundant sedimentary rocks along with lesser volcanic rocks. The chemical characteristics of the basalts in the southern MRS are similar to those in the north. The southern basalts are subalkalic to alkalic and follow tholeiitic trends; a number of them are high-alumina basalts. Although there is a lot of scatter, Al2O3, Ni, and Cr concentrations decrease and Fe2O3, TiO2, K2O, rare earth elements, Ba, Hf, and Sc concentrations increase with decreasing Mg number. These trends are consistent with plagioclase, olivine, pyroxene, or spinel fractionation from primary basalts. One basalt could represent a primary magma because it has a high Mg number (0.68), high Ni (638 mg/kg) and Cr (233 mg/kg) concentrations, low incompatible element concentrations (e.g., La = 4.2 mg/kg), and a slight positive Eu anomaly. This possible primary magma could have formed by partial melting (20-25%) of an undepleted spinel peridotite at 30-40 km depth. Most basalts have not been contaminated by crustal rocks or silicic magmas. The mineralogy, chemical composition, and U-Pb geochronology of detrital zircons of the arkoses, siltstones, and shales are consistent with their derivation from the surrounding granitoid highlands with little or no input from the basalts. Even siltstones and arkoses within the mostly basaltic sequences are derived mostly from the granitoids, although the siltstones may have some input from the basalts (e.g., higher Ni concentration than the sandstones).

Robert L. Cullers

Pieter Berendsen

Composition of Rift-Related Igneous and Sedimentary Rocks of the Keweenawan Supergroup in the Poersch No. 1, OZ-1, Finn, and Friederich Wells, Northeastern Kansas

东北堪萨斯波尔施1号、OZ-1、芬恩和弗里德里希威尔斯的基维诺超群裂谷相关火成岩和沉积岩的组成

Ten cyclothems from the Wolfcampian of northeastern Kansas, including parts of the Council Grove and Chase Groups, were examined in detail with particular attention to discontinuity surfaces and paleosol development. These cyclothems are shown to be bounded by major discontinuities, or sequence boundaries, where marine limestones abruptly overlie paleosol profiles. Occurring within these cyclothemic sequences are prominent meter-scale cycles that are bounded by flooding surfaces, many of which overlie facies exhibiting evidence of subaerial exposure. They are developed within both the marine carbonate and shale intervals and variegated mudstone intervals of the cyclothems. These meter-scale cycles show a consistent carbonate-to-clastic pattern regardless of their stratigraphic position or component facies. Climate fluctuations within a generally monsoonal environment are determined to be the most likely forcing mechanism for the meter-scale cycles, with wetter climate phases resulting in the increased influx of terrigenous clastic sediment and drier climate phases favoring carbonate precipitation. Evidence of climate change at the scale of the cyclothemic sequences is also recognized in the studied interval. Cycles at both scales indicate that relative sea-level rise was associated with increasingly arid conditions and that sea-level fall was associated with an intensification of seasonal rainfall.

Keith B. Miller

Ronald R. West

Reevaluation of Wolfcampian Cyclothems in Northeastern Kansas

重新评估堪萨斯州东北部狼营阶的旋回层序

In his reports on the regional hydrogeology of the central Great Plains, in particular southeastern Colorado and southwestern and central Kansas, Darton considered the Dakota aquifer to be a classic example of an artesian system. Computer simulations of the flow system in this study, however, suggest that the Dakota is not a regional artesian aquifer in the classic sense. Sensitivity analysis of a steady-state vertical profile flow model demonstrates that the flow system in the upper Dakota in western Kansas is heavily influenced by the Upper Cretaceous aquitard, the Arkansas River in southeastern Colorado, and rivers in central Kansas, such as the Saline, that have eroded through the aquitard and into the Dakota to the west of the main outcrop area of the aquifer. The model shows that local flow systems and the vertical hydraulic conductivity of the Upper Cretaceous aquitard heavily influence the water budget and the flow patterns. The aquitard restricts recharge from the overlying water table to underlying aquifers in western Kansas because of its considerable thickness and low vertical hydraulic conductivity. The Arkansas River intercepts ground-water flow moving toward western Kansas from recharge areas south of the river and further isolates the upper Dakota from sources of freshwater recharge. In central Kansas, the Saline River has reduced the distance between confined portions of the aquifer and its discharge area. In essence, this has improved the hydraulic connection between the confined aquifer and its discharge area, thus helping to generate subhydrostatic conditions in the upper Dakota upgradient of the river.

P. Allen Macfarlane

The Effect of River Valleys and the Upper Cretaceous Aquitard on Regional Flow in the Dakota Aquifer in the Central Great Plains of Kansas and Southeastern Colorado

河流谷地和上白垩纪隔水层对堪萨斯州和科罗拉多州东南部大平原达科他含水层区域流动的影响

This paper reviews proposed Mississippian nomenclature changes in Kansas and outlines the changes to Zeller (1968) that have been adopted by the Kansas Geological Survey. The Sedalia Dolomite is changed to the Sedalia Formation and the Northview Shale is changed to Northview Formation due to lateral lithology changes. The Short Creek Oolite Member as originally defined and described by Smith and Siebenthal (1907) at the type section in Kansas is reinstated. The Cowley Formation as originally defined and described by Lee (1940) in Kansas is reinstated. The Ste. Genevieve Limestone is placed as the basal formation of the Chesteran Stage.

Evan K. Franseen

Robert S. Sawin

Anthony L. Layzell

Greg A. Ludvigson

Mississippian Stratigraphic Nomenclature Revisions in Kansas

堪萨斯州密西西比纪地层命名修订

This paper outlines Quaternary nomenclature changes to Zeller (1968) that have been adopted by the Kansas Geological Survey (KGS). The KGS formally recognizes two series/epochs for the Quaternary: the Holocene and Pleistocene. Pleistocene stage/age names Kansan, Aftonian, Nebraskan, and Yarmouthian are abandoned and replaced with the broader term "pre-Illinoian." Formation names Bignell, Peoria, Gilman Canyon, and Loveland are maintained for loess units. Formation names for the following alluvial lithostratigraphic units are abandoned: Crete, Sappa, Grand Island, Fullerton, and Holdrege. The Severance Formation is adopted as a new lithostratigraphic unit for thick packages of late Pleistocene alluvium and colluvium in Kansas. The DeForest Formation is accepted as a valid lithostratigraphic unit for deposits of fine-grained Holocene alluvium in Kansas. Formation names Iowa Point, Nickerson, and Cedar Bluffs for glacial tills and Atchison and David City for glaciofluvial deposits are abandoned. The Afton and Yarmouth Soils are abandoned as pedostratigraphic units, whereas the Sangamon Geosol and Brady Geosol are maintained.

Rolfe D. Mandel

Quaternary Stratigraphy and Stratigraphic Nomenclature Revisions in Kansas

堪萨斯州第四纪地层与地层命名修订

The age of red beds exposed below the bluff-capping Ogallala Formation at Point of Rocks in Morton County, Kansas, has been disputed since they were first recognized in the late 1800s. Over the years, nearly 25 maps and reports have variously classified the strata as Cretaceous, Jurassic, Triassic, or Permian, creating an interesting history of speculation and stratigraphic nomenclature. Many of the interpretations relied on the indirect method of comparing lithologies to similar exposures in surrounding states, but none were in-depth studies. Until recently, the Kansas Geological Survey has considered the rocks to be Jurassic based on Zeller (1968), the currently recognized stratigraphic guide and chart for Kansas. A comprehensive study by Smith et al. (2015)--using outcrop descriptions, subsurface information, and detrital zircon data--constrained the age of the red beds at Point of Rocks, assigning them to the Guadalupian Big Basin Formation, the uppermost Permian unit in Kansas.

Classification of Red Beds at Point of Rocks, Morton County, Kansas

堪萨斯州莫顿县岩石点红层分类

Point of Rocks, a high-relief bluff overlooking the Cimarron River valley in Morton County, Kansas, is capped by distinct white beds of Neogene Ogallala Formation calcrete that overlie red beds of shale, siltstone, and sandstone. These unfossiliferous red beds are currently assigned to the Jurassic System; however, their age has long been debated due to a lack of marker beds, index fossils, and nearby correlative outcrops. As a result, geologists over the years have assigned the rocks to systems ranging from the Permian to the Cretaceous. In this study, four stratigraphic sections were measured in the red beds and three bulk samples were collected to determine the uranium-lead age distributions of detrital zircon (DZ) populations. Red-bed strata composed of fissile shale and sandstone are interpreted as alluvial overbank deposits, while dominantly trough cross-bedded and planar-laminated sandstones are interpreted as tidally influenced fluvial deposits. Detrital zircon age peaks can be grouped into at least seven subpopulations with a youngest single zircon age of 263.8 ± 12.1 Ma, a more conservative age of 293.0 ± 6.95 Ma based on the youngest grouping of three grain ages overlapping at 2σ, and a complete absence of Mesozoic age zircons. In addition, copper oxides along partings and fractures suggest that the red beds once hosted copper sulfides, a common constituent of regional Permian-Triassic red beds. The DZ data--in conjunction with the identification of the Permian Day Creek Dolomite marker bed in logs of nearby drilling tests--strongly suggest that the enigmatic red beds cropping out at the base of Point of Rocks should be assigned to the Guadalupian Big Basin Formation, the uppermost Permian unit in Kansas.

Jon J. Smith

Brian F. Platt

Craig P. Marshall

Alison Olcott-Marshall

Enigmatic Red Beds Exposed at Point of Rocks, Cimarron National Grassland, Morton County, Kansas

堪萨斯州莫顿县西马伦国家草原岩石点暴露出的神秘红层

The informal stratigraphic term "Precambrian" is replaced by formal nomenclature--Proterozoic and Archean Eonothems/Eons--and the informal term Hadean. The Phanerozoic Eonothem/Eon, representing all rocks younger than the Proterozoic, is added. The Proterozoic is further divided into Paleoproterozoic, Mesoproterozoic, and Neoproterozoic Erathems/Eras. The name Rice Formation (Scott, 1966) is abandoned, and the use of the informal term "Rice unit" is recommended. The proposed name Rice Series (Berendsen, 1994) is not accepted. These changes are adopted by the Kansas Geological Survey (KGS) and the stratigraphic nomenclature of Zeller (1968) has been revised accordingly.

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