Lindley Hanson's List: Geomorphology-references

USGS Guide to landslides

Classification and glossary of landslides

KARST AQUIFER SYSTEMS
Tectonic Control of Hypogene Speleogenesis in the southern Ozarks -- Implications for NAWQA and Beyond

By Rodney Tennyson1, Jim Terry2, Van Brahana3, Phil Hays4, and Erik Pollock5

1MOLES, 1303 CR 919, Alpena, AR 72611
2MOLES, 1103 W. Olive, Rogers, AR 72756
3Department of Geosciences, 113 Ozark, University of Arkansas, Fayetteville, AR 72701 and Research Hydrologist Emeritus, U.S. Geological Survey
4Department of Geosciences and U.S. Geological Survey, 113 Ozark, University of Arkansas, Fayetteville, AR 72701
5Stable Isotope Lab, Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701

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Abstract

The Ozark Plateaus are an ancient, variably karstified region of the mid-continent that have more than 8000 reported caves, tens of thousands of springs, and a wide and diverse suite of accompanying karst landforms and hydrogeologic features. The importance of aquifers of the Ozark Plateaus led to their inclusion as one of the initial National Water-Quality Assessment study units in 1991, and the resulting studies have enhanced significantly our understanding of the processes and controls affecting water quality throughout the region.

This report describes the integration of recent data from diverse types of research to develop a conceptual model of hypogene speleogenesis for one selected data set of cave and karst locations within the Ozark Plateaus that overlie or are contiguous to deep basement faults. Data encompass geologic mapping, cave mapping, structural geology, gravity mapping, hydrogeology, ground-water tracing, endangered species distribution mapping, cave mineralogy, stable-isotope geochemistry, and fluid inclusion studies. This conceptual model draws on reactivation of preexisting basement faults during tectonic pulses, with the formation of caves and selected cave minerals created by geothermally heated

"GEOLOGY OF THE MAMMOTH CAVE AREA

By Arthur N. Palmer

Reprinted with permission of the author and Mammoth Cave National Park

Mammoth Cave is the longest known cave in the world, with about 350 miles of interconnected passages known today. Exploration and mapping continue, and there is no end in sight. The cave consists of several large sections explored separately through various entrances and connected by later discoveries (Figure 1). It is located mainly within Mammoth Cave National Park, established in 1941 and administered by the National Park Service. The Park was designated a World Heritage Site in 1981 on the basis of its geological, archaeological, and biological significance, and it was designated an International Biosphere Reserve in 1990. About 9 miles of trails in the cave are open to the public on a variety of guided tours.

A landscape that is dominated by solutional features such as sinkholes, sinking streams, caves, and large springs is known as karst. This name comes from a plateau in western Slovenia (south of Austria ) where some of the earliest studies of these features were made. Figure 2 shows the extent of karst regions and volcanic caves in the USA.

The cave is located in a low plateau of limestone, a rock that dissolves readily in most natural water. The great majority of caves are formed by the dissolving action of underground water as it seeps through the cracks in limestone. This particular limestone was originally deposited on the floor of a shallow sea that covered this part of the continent about 330-340 million years ago. At Mammoth Cave the limestone is capped by insoluble rocks, mainly sandstone, which form a resistant cap over the cavernous rocks below. This cap-rock helps to protect the upper-level passages in the cave from being eroded away. The rock layers are tilted an average of about 0.3 degrees toward the northwest (Figure 3).

The sandstone-capped region is called the Chester Upland (Figure 4). It rises to about 800 ft above sea level. Stream erosion has carved valley

Hypogene Processes in the Edwards Aquifer in South-Central Texas, a New Conceptual Model to Explain Aquifer Dynamics*

Geary M. Schindel1, Steven Johnson1, and E. Calvin Alexander2



Search and Discovery Article #80019 (2008)

Posted October 25, 2008



*Adapted from oral presentation at AAPG Annual Convention, San Antonio, TX, April 20-23, 2008

1Aquifer Science, Edwards Aquifer Authority, San Antonio, TX (gschindel@mindspring.com)

2Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN.
Abstract


The Balcones Fault Zone Edwards Aquifer of south-central Texas is one of the most important karst aquifers in the United States and provides water to 1.7 million people and for critical habitat for endangered species. The Edwards Aquifer extends 400 kilometers from Del Rio, east to San Antonio though Austin, and northeast to Bell County. The aquifer is from 10 to 60 kilometers wide and in places, more than 1,200 meters. The aquifer is contained within the Edwards Group limestone and associated units (Georgetown limestone). The Edwards and associated units were deposited in late Early Cretaceous time and are 150 to more than 300 meters thick. The Edwards Limestone, since deposition, has undergone subaerial exposure, burial in the middle Cretaceous, faulting in the Miocene, uplift and erosion. Faulting is mainly northeast-southwest trending, down to the gulf, en echelon normal faulting. Researchers have proposed epigene (near surface) karst processes, driven by circulating meteoric waters, formed the aquifer along paleokarst features. New interpretations suggest an additional process that contributed to the formation and structure of the Edwards Aquifer. Epigenetic karst theory assumes karst features are produced only during its downward or horizontal groundwater movement, but Klimchouk (2008) concludes that rising waters from depth are important agents of karst development. Regional flow systems, such as the Edwards Aquifer, terminate in springs where the groundwater returns to the surface.

"Morphogenesis of hypogenic caves

KLIMCHOUK Alexander (1) ;

(1) Ukrainian Institute of Speleology and Karstology, 4 Prospect Vernadskogo, Simferopol 95007, UKRAINE
Résumé / Abstract
Hypogenic speleogenesis is the formation of solution-enlarged permeability structures by waters ascending to a cave-forming zone from below in leaky confined conditions, where deeper groundwaters in regional or intermediate flow systems interact with shallower and more local groundwater flow systems. This is in contrast to more familiar epigenic speleogenesis which is dominated by shallow groundwater systems receiving recharge from the overlying or immediately adjacent surface. Hypogenic caves are identified in various geological and tectonic settings, formed by different dissolutional mechanisms operating in various lithologies. Despite these variations, resultant caves demonstrate a remarkable similarity in patterns and meso-morphology, which strongly suggests that the hydrogeologic settings were broadly identical in their formation. Hypogenic caves commonly demonstrate a characteristic suite of cave morphologies resulting from rising flow across the cave-forming zone with distinct buoyancy-dissolution components. In addition to hydrogeological criteria (hydrostratigraphic position, recharge-discharge configuration and flow pattern viewed from the perspective of the evolution of a regional groundwater flow system), morphogenetic analysis is the primary tool in identifying hypogenic caves. Cave patterns resulting from ascending transverse speleogenesis are strongly guided by the permeability structure in a cave formation. They are also influenced by the discordance of permeability structure in the adjacent beds and by the overall hydrostratigraphic arrangement. Three-dimensional mazes with multiple storeys, or complex 3-D cave systems are most common, although single isolated chambers, passages or crude clusters of a few intersecting passages may occur where fracturing is scarce and laterally discontinuous. Large rising shafts and

ABSTRACT
Hypogene speleogenesis is widespread throughout the Delaware Basin region as evidenced by intrastratal dissolution, hypogenic caves and suites of diagenetic minerals. The world famous carbonate caves of the Capitan reef facies of the Guadalupe Mountains have long been associated with sulfuric acid processes and recently have been associated with semi-confined, hypogene dissolution. However, evaporite karst within Permian
backreef and basin-filling facies has been traditionally associated with surficial, epigene processes. On the eastern edge of the Delaware Basin cavernous porosity associated with
oil reservoirs in Permian carbonates have been attributed to eogenetic karst processes. Interbedded (evaporite / carbonate), backreef facies within the Seven Rivers Formation exhibit characteristics of hypogene dissolution associated with semi-confined dissolution controlled by the eastward migration and entrenchment of the Pecos River. Coffee Caves is a classic example of hypogene dissolution, forming a multi-storey,
rectilinear maze with abundant morphologic features suites (i.e. risers, channels and
cupolas) indicative of hypogene speleogenesis. Other caves within the Seven Rivers and Rustler Formations show similar patterns, yet often less developed. Within the Delaware Basin, Castile Formation evaporites have been extensively modified by hypogene processes. Field mapping coupled with GIS analyses clearly shows karst development and evaporite calcitization are highly clustered throughout the outcrop area. Individual caves commonly exhibit complex morphologies, including
complete suites of morphologic features indicative of intrastratal dissolution. Clusters of hypogene caves are commonly associated with clusters of evaporite calcitization and often occurrences of secondary selenite bodies, suggesting all three are genetically
related. Brecciated cores and associated native sulfur deposits indicate that calcitized occurrences are the result of semi-confined sulfate reduction in the presence

Sulfuric Acid Speleogenesis of Carlsbad Cavern and Its Relationship to Hydrocarbons, Delaware Basin, New Mexico and Texas (1)
CAROL A. HILL
AAPG Bulletin
Volume 74, Issue 11. (November), Pages 1685 - 1694 (1990)

Sulfur-isotope data and pH-dependence of the mineral endellite support the hypothesis that Carlsbad Cavern and other caves in the Guadalupe Mountains were dissolved primarily by sulfuric acid rather than by carbonic acid. Floor gypsum deposits up to 10 m thick and native sulfur in the caves are significantly enriched in {32}S; (isotope){34}S values as low as -25.8 per mil (CDT) indicate that the cave sulfur and gypsum are the end products of microbial reactions associated with hydrocarbons. A model for a genetic connection between hydrocarbons in the basin and caves in the Guadalupe Mountains is proposed. As the Guadalupe Mountains were uplifted during the late Pliocene-Pleistocene, oil and gas moved updip in the basin. The gas reacted with sulfate anions derived from dissolution of the Castile anhydrite to form H[2]S, CO[2], and "castile" limestone. The hydrogen sulfide rose into the Capitan reef along joints, forereef carbonate beds, or Bell Canyon siliciclastic beds and there reacted with oxygenated groundwater to form sulfuric acid and Carlsbad Cavern. A sulfuric-acid mode of dissolution may be responsible for large-scale porosity of some Delaware basin reservoirs and for oil-field karst reservoirs in other petroleum basins of the world. "

"The BSG is the professional organisation for British geomorphologists and provides a community and services for those involved in teaching or research in geomorphology, both in the UK and overseas. The BSG promotes the field of geomorphology, encouraging interests in: earth surface process, and the erosion, deposition and formation of landforms and sediments. Foci include the physical geography of our river, valley, glacier, mountain, hill, slope, coast, desert and estuary environments; alongside responses to Holocene, Pleistocene or Quaternary environmental change. These pages outline BSG activities, and include details of:- forthcoming meetings, conferences and field excursions; publications (the Geophemera newsletter and the academic journal Earth Surface Processes and Landforms); research funding; educational resources for schools; and membership details. "