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The AAPG/Datapages Combined Publications Database

Showing 3,218 Results. Searched 200,619 documents.

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Modeling the Semivariogram: New Approach, Methods Comparison, and Simulation Study

A. Gribov, K. Krivoruchko, J. M. Ver Hoef

AAPG Special Volumes

..., spherical or exponential) to the values. Three main approaches exist for estimating the parameters of the semivariogram model: visual, (weighted) least...

2006

Petrologic Method for Distinguishing Eolian and Marine Grainstones, Ste. Genevieve Limestone (Mississippian) of Indiana: Chapter 4

J. Robert Dodd, Charles W. Zuppann, Clayton D. Harris, Karl W. Leonard, Thomas W. Brown

AAPG Special Volumes

... grains not originally spherical is low. Fine laminations are not present, and no systematic grading is found on a thin-section scale. Fossils larger...

1993

Pisolites Formed from the Oilfield Water of the Luling Field, Caldwell County, Texas

Augusta Hasslock Kemp

Journal of Sedimentary Research (SEPM)

... agitated pools on the floor below.< P> The pisolites ranged from 3 mm to 50 mm in diameter, and their shapes ranged from spherical to ovoid...

1959

A Peculiar Pedestalate Terrace, San Nicolas Island, California: NOTES

Harold D. Palmer , David W. Scholl , Jack Green

Journal of Sedimentary Research (SEPM)

... to moderately well sorted medium grained arkosic sandstone [in which] large elongate to nearly spherical calcareous concretions ... occur in some...

1965

A Rapid Method for Determining Weight Percentages of Unsieved Heavy Minerals

Ralph E. Hunter

Journal of Sedimentary Research (SEPM)

...) for spherical grains of a given density () is easily calculated by the formula: grain weight=d3/6. Natural sand grains, however, are usually not spherical...

1967

Glossary

Joann E. Welton

AAPG Special Volumes

...-sea oozes of the temperate and tropical oceans, and were probably not common before the Jurassic. coccosphere: The entire spherical or spheroidal...

1984

Abstracts: An Investigation of Systematic Location Errors of Microseismic Events; #90173 (2015)

Martin E. Nicola, Bernd Milkereit, and Emmanuel Bongajum

Search and Discovery.com

... to the triangles in the plots. As expected, the contours are spherical. Receivers have been subjectively set to obtain travel time values only for their positions...

2015

Abstracts: Influence of Hydrothermal Fluids on the Horn River Shale Sequence; #90173 (2015)

Ronald J. Spencer, Thomas Weedmark, Victoria Biersteker, and Jon Dola

Search and Discovery.com

... tests are nearly spherical in the silica cemented and dolomite cemented examples in Figure 3 (left and right), but flattened in the uncemented example...

2015

Analysis of the Relations between Porosity and Permeability in Non-Consolidated Granular Media, #40970 (2012)

Melia Da Silva, Carlos Santos

Search and Discovery.com

... studied, and three relations were proposed after analyzing the 2D distribution of the pore throat radii in monodisperse and spherical granular samples...

2012

Diagenetic and Compositional Controls of Wettability in Siliceous Sedimentary Rocks, Monterey Formation, California; #51111 (2015)

Kristina M. Hill and Richard J. Behl

Search and Discovery.com

... (spherical droplets, left) and quartz (low dome droplets, right) in sandstone, showing contrasting wetting characteristics of different mineral surfaces (image...

2015

Unsteady-state diffusion modeling of gas in coal matrix for horizontal well production

Jian-Chun Guo, Ren-Shi Nie, and Yong-Lu Jia

AAPG Bulletin

... assumptions were adopted, such as the spherical matrix elements (Ertekin and Sung, 1989; Anbarci and Ertekin, 1990, 1991) and uniform entry into the well...

2014

Passageways for permeability: Geostatistical simulation of controls on the connectivity of vug-to-vug pore networks

Hassan A. Eltom, Eugene C. Rankey, Robert H. Goldstein, and Reza Barati

AAPG Bulletin

.... The modeled shapes are inspired by vugs in the stratigraphic record. The spherical shape, for example, resembles vugs from dissolved evaporite nodules...

2023

Size Analysis of Sand by a Sedimentation Technique

David M. Poole

Journal of Sedimentary Research (SEPM)

... experimentally (among others, Heywood, 1938; U. S. Engineers 1941, 1943) for single spherical grains. The use of single spheres in these experiments obviously...

1957

Determination of Average Grain Sphericity in Granular Porous Media

Basanta K. Sahu

Journal of Sedimentary Research (SEPM)

... surface of the natural porous media as well as of specific spherical surface per unit solid volume if the natural irregular grains are replaced...

1974

Experimental Hydrothermal Alteration of Tholeiitic Basalt: Resultant Mineralogy and Textures

J. B. Keene, David A. Clague , Richard K. Nishimori

Journal of Sedimentary Research (SEPM)

... to that occurring in hydrothermal experiments (Fig. 3). Scale bar = 10 µm. 11. Alteration of glass fragments forms clays and spherical fragments. Similar...

1976

Origin of Oolitic Iron Formations: REPLY

Michael M. Kimberley

Journal of Sedimentary Research (SEPM)

... structure of calcareous and ferriferous ooids. First, they note that ferriferous ooids are generally less spherical than calcareous ooids. Although...

1980

Settling Velocities of Irregular Grains at Low Reynolds Numbers

Jumpei Baba, Paul D. Komar

Journal of Sedimentary Research (SEPM)

.... Yet nearly all previous studies have employed fairly regular if non-spherical grains: ellipsoids (Komar and Reimers, 1978), cylinders (McNown...

1981

Ventura Basin Edge Environment: GEOLOGICAL NOTES

Herbert Skolnick , Robert E. Arnal

AAPG Bulletin

... yellow, highly metallic octahedra in irregular and spherical aggregates; very thin coal streaks throughout matrix; very rare "carbonaceous" films; rare...

1959

Depositional Environments of the Topanga CanyonŽ Formation, the Encinal Tongue of the Rincon Shale, and the Fernwood Tongue of the Sespe Formation, Central Santa Monica Mountains, California

Michael E. Flack

Pacific Section SEPM

... contacts. Rounded pebbles are unoriented, spherical to discoidal, and granitic and quartzitic in composition. Burrows are larger and less concentrated than...

1993

Radiolarites and their Relation to Subjacent "Oceanic Crust" in Liguria, Italy

Robert L. Folk, Earle F. Mcbride

Journal of Sedimentary Research (SEPM)

... to neck or break when the interbedded less lithified mud (shale) deformed by flowage. Odd sausage-like to spherical bodies of chert that are now encased...

1978

The Rounding of Sand Grains

W. H. Twenhofel

Journal of Sedimentary Research (SEPM)

... and water transportation and there is no known way of determining from these sands the degree of responsibility. If a sample of highly spherical and well...

1945

Mineralogy and Petrology of the Cretaceous-Tertiary Boundary Clay Bed and Adjacent Clay-Rich Rocks, Raton Basin, New Mexico and Colorado

Richard M. Pollastro, Charles L. Pillmore

Journal of Sedimentary Research (SEPM)

... in the boundary bed was probably rapid, leading to hydrated, disordered, fine-grained clay minerals that formed into curled spherical or tubular shapes...

1987

Cross-Shore Distribution of Sediment Texture Under Breaking Waves Along Low-Wave-Energy Coasts

Ping Wang , Richard A. Davis, Jr. , Nicholas C. Kraus

Journal of Sedimentary Research (SEPM)

... by the percent carbonate concentration in the sediment samples. The rest of the sediment was composed mainly of spherical quartz grains. The platy shell debris...

1998

Origin of Red-Banded Early Cenozoic Deposits in Rocky Mountain Region

F. B. Van Houten

AAPG Bulletin

... of the enclosing rock. A 6-inch layer of fibrous hematite composed of spherical particles about 1.2 millimeter in diameter and a 2-3-inch layer of irregular...

1948

Sedimentologic, Diagenetic, and Geochemical Analysis of Upper Mesozoic Ribbon Cherts from the Franciscan Assemblage at the Marin Headlands, California

S. M. Karl

Pacific Section SEPM

... (conical) and spumellarian (spherical) radiolarian tests of different sizes are evenly distributed in the matrix. Test rims are composed of 75...

1984

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