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Warren D. Huff

Bio: Warren D. Huff is an academic researcher from University of Cincinnati. The author has contributed to research in topics: Ordovician & Illite. The author has an hindex of 36, co-authored 115 publications receiving 4579 citations. Previous affiliations of Warren D. Huff include University of California, San Diego & Kongju National University.
Topics: Ordovician, Illite, Paleozoic, Laurentia, Baltica


Papers
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Journal ArticleDOI
TL;DR: Elliott et al. as discussed by the authors used X-ray Diffraction and the Identification and Analysis of Clay Minerals to identify and analyze the properties of clays in the soil.
Abstract: Instructor: Dr. W. Crawford Elliott, Associate Professor, Department Chair Office: 331 Kell Hall Office Phone: (404) 413-5756 E-mail: wcelliott@gsu.edu Primary Texts: X-ray Diffraction and the Identification and Analysis of Clay Minerals, by D.M. Moore and Robert C. Reynolds, Jr. (2nd Edition), 1997, Oxford University Press. Office Hours: 4-5 pm M, anytime the door is open, or by appointment. Lectures: M, W, 5:30pm – 7:10 pm, Kell 314. Laboratory: By arrangement, see below.

1,319 citations

Journal ArticleDOI
01 Oct 1992-Geology
TL;DR: The Millbrig K-bentonite has been identified in both North America and Europe, and it serves as a unique event-stratigraphic marker over a large portion of the Northern Hemisphere as discussed by the authors.
Abstract: Biostratigraphical, geochemical, isotopic, and paleogeographic data suggest that the Millbrig K-bentonite, one of the thickest and most widespread Ordovician volcanic ash beds in eastern North America, is the same as the so-called 'Big Bentonite' in Baltoscandia. This is the first time that the same K-bentonite has been identified in both North America and Europe, and it serves as a unique event-stratigraphic marker over a large portion of the Northern Hemisphere. This eruption produced at least 340 km[sup 3] of dense-rock-equivalent ash that was deposited in a layer up to 1-2 m thick over several million square kilometers. As much as 800 km[sup 3] of additional ash may have fallen into the Iapetus Ocean, for a total of 1,140 km[sup 3]. Trace element geochemistry shows that the ash was derived from a felsic calc-alkalic magmatic source characteristic of volcanism in a continental crust-based, destructive plate-margin setting. This is one of the largest, if not the largest, ash falls recorded in Earth's Phanerozoic stratigraphic record, but its recognizable effect on faunas and floras was minimal, and it did not result in a global extinction event. The Millbrig-Big Bentonite bed provides accurate time control for sedimentologic, paleoecologic, and paleogeographic reconstructions across plates positionedmore » in tropical (Laurentia) and temperate (Baltica) latitudes during Middle Ordovician time.« less

188 citations

Journal ArticleDOI
TL;DR: In this paper, geochemical analyses of K-bentonites show that the parent magma originated in syn-collisional, volcanic-arc and within-plate tectonic settings, which produced mainly intermediate-to-felsic series magmas associated with continuous collision and subduction of paleo-continental blocks/arcs.

161 citations

Journal ArticleDOI
TL;DR: A SHRIMP U-Pb zircon age of 1437±21 Ma was obtained for a recently discovered K-bentonite bed in the Tieling Formation, situated northeast of Beijing at the boundary between Liaoning and Hebei provinces, on the northern margin of the North China Craton (NCC).
Abstract: A SHRIMP U-Pb zircon age of 1437±21 Ma was obtained for a recently discovered K-bentonite bed in the Tieling Formation, situated northeast of Beijing at the boundary between Liaoning and Hebei provinces, on the northern margin of the North China Craton (NCC). The SHRIMP U-Pb age places Tieling Formation near the end of the Calymmian Period of the early Mesoproterozoic Era. In addition, a SHRIMP U-Pb zircon date of 1372±18 Ma was acquired for K-bentonite beds in the overlying, dark-shale-dominated Xiamaling Formation from the same location northeast of Beijing. This date assigns a similar Mid-Mesoproterozoic (Ectasian Period) age for the Xiamaling Formation, as have previously determined dates from other sections northwest of Beijing. These dates indicate that the Tieling and Xiamaling formations, as well as the related succession in the eastern part of the Yanshan Mountains, represented by the well-known Meso- to Neoproterozoic standard section in Jixian, can be correlated well with sections northwest of Beijing in the western part of the Yanshan Mountains. In other words, the boundary between the Calymmian and Ectasian periods in the northern parts of the NCC is marked by the unconformity between the Tieling and Xiamaling formations in the northern NCC. This boundary was previously ascribed to the “Qinyu Orogeny” and thought to be of Grenville age. In this regard, the conventional “Qinyu Orogeny” should now be regarded as a short-lived regional uplift during Early Mesoproterozoic time, rather than a result from the Grenvillian assembly of the NCC to the Rodinia Supercontinent (∼1.0 Ga).

130 citations

Journal ArticleDOI
01 Apr 2009-Elements
TL;DR: Bentonites are clay rocks consisting predominantly of smectite as discussed by the authors, and they form mainly from alteration of pyroclastic and/or volcaniclastic rocks and are useful for stratigraphic correlation and for interpreting the geodynamic evolution of our planet.
Abstract: Bentonites are clay rocks consisting predominantly of smectite. They form mainly from alteration of pyroclastic and/or volcaniclastic rocks. Extensive deposits, linked to large eruptions, have formed repeatedly in the past. Bentonite layers are useful for stratigraphic correlation and for interpreting the geodynamic evolution of our planet. Bentonites generally form by diagenetic or hydrothermal alteration, favoured by fluids that leach alkali elements and by high Mg content. Smectite composition is partly controlled by parent rock chemistry. Recent studies have shown that bentonite deposits may display cryptic variations in layer charge - i.e. the variations are not visible at the macroscopic scale - and these correlate with physical properties.

129 citations


Cited by
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Journal ArticleDOI
TL;DR: A review of chitosan composites for removing dyes and heavy metal ions can be found in this article, where a list of composites with their adsorption capacity and experimental conditions has been compiled.

1,746 citations

Book
01 Jan 2013
TL;DR: In this article, the authors defined the sources of heavy metals and metalloids in Soils and derived methods for the determination of Heavy Metals and Metalloids in soil.
Abstract: Preface.- Contributors.- List of Abbreviations.- Section 1: Basic Principles: Introduction.-Sources of Heavy Metals and Metalloids in Soils.- Chemistry of Heavy Metals and Metalloids in Soils.- Methods for the Determination of Heavy Metals and Metalloids in Soils.- Effects of Heavy Metals and Metalloids on Soil Organisms.- Soil-Plant Relationships of Heavy Metals and Metalloids.- Heavy Metals and Metalloids as Micronutrients for Plants and Animals.-Critical Loads of Heavy Metals for Soils.- Section 2: Key Heavy Metals And Metalloids: Arsenic.- Cadmium.- Chromium and Nickel.- Cobalt and Manganese.- Copper.-Lead.- Mercury.- Selenium.- Zinc.- Section 3: Other Heavy Metals And Metalloids Of Potential Environmental Significance: Antimony.- Barium.- Gold.- Molybdenum.- Silver.- Thallium.- Tin.- Tungsten.- Uranium.- Vanadium.- Glossary of Specialized Terms.- Index.

1,684 citations

Journal ArticleDOI
TL;DR: In this paper, the authors compare the timing of mass extinctions with the formation age of large igneous provinces and reveal a close correspondence in five cases, but previous claims that all such provinces coincide with extinction events are unduly optimistic.

1,082 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examine possible causative relations between tectonics and environmental and biologic changes during the Neoproterozoic and Paleozoic eras by reconstructing Rodinia and Pannotia, supercontinents that may have existed before and after the opening of the Pacific Ocean basin.
Abstract: The ever-changing distribution of continents and ocean basins on Earth is fundamental to the environment of the planet. Recent ideas regarding pre-Pangea geography and tectonics offer fresh opportunities to examine possible causative relations between tectonics and environmental and biologic changes during the Neoproterozoic and Paleozoic eras. The starting point is an appreciation that Laurentia, the rift-bounded Precambrian core of North America, could have been juxtaposed with the cratonic cores of some present-day southern continents. This has led to reconstructions of Rodinia and Pannotia, supercontinents that may have existed in early and latest Neoproterozoic time, respectively, before and after the opening of the Pacific Ocean basin. Recognition that the Precordillera of northwest Argentina constitutes a terrane derived from Laurentia may provide critical longitudinal control on the relations of that craton to Gondwana during the Precambrian-Cambrian boundary transition, and in the early Paleozoic. The Precordillera was most likely derived from the general area of the Ouachita embayment, and may have been part of a hypothetical promontory of Laurentia, the “Texas plateau,” which was detached from the Cape of Good Hope embayment within Gondwana between the present-day Falkland-Malvinas Plateau and Transantarctic Mountains margins. Thus the American continents may represent geometric “twins” detached from the Pannotian and Pangean supercontinents in Early Cambrian and Early Cretaceous time, respectively—the new mid-ocean ridge crests of those times initiating the two environmental supercycles of Phanerozoic history 400 m.y. apart. In this scenario, the extremity of the Texas plateau was detached from Laurentia during the Caradocian Epoch, in a rift event ca. 455 Ma that followed Middle Ordovician collision with the proto-Andean margin of Gondwana as part of the complex Indonesian-style Taconic-Famatinian orogeny, which involved several island arc-continent collisions between the two major continental entities. Laurentia then continued its clockwise relative motion around the proto-Andean margin, colliding with other arc terranes, Avalonia, and Baltica en route to the Ouachita-Alleghanian-Hercynian-Uralian collision that completed the amalgamation of Pangea. The important change in single-celled organisms at the Mesoproterozoic-Neoproterozoic boundary (1000 Ma) accompanied assembly of Rodinia along Grenvillian sutures. Possible divergence of metazoan phyla, the appearance and disappearance of the Ediacaran fauna (ca. 650–545 Ma), and the Cambrian “explosion” of skeletalized metazoans (ca. 545–500 Ma) also appear to have taken place within the framework of tectonic change of truly global proportions. These are the opening of the Pacific Ocean basin; uplift and erosion of orogens within the newly assembled Gondwana portion of Pannotia, including a collisional mountain range extending ≈7500 km from Arabia to the Pacific margin of Antarctica; the development of a Pannotia-splitting oceanic spreading ridge system nearly 10 000 km long as Laurentia broke away from Gondwana, Baltica, and Siberia; and initiation of subduction zones along thousands of kilometres of the South American and Antarctic-Australian continental margins. The Middle Ordovician sea-level changes and biologic radiation broadly coincided with initiation of the Appalachian-Andean mountain system along >7000 km of the Taconic and Famatinian belts. These correlations, based on testable paleogeographic reconstructions, invite further speculation about possible causative relations between the internally driven long-term tectonic evolution of the planet, its surface environment, and life.

1,053 citations

Journal ArticleDOI
15 Sep 2000-Science
TL;DR: Fossilized fungal hyphae and spores from the Ordovician of Wisconsin strongly resemble modern arbuscular mycorrhizal fungi (Glomales, Zygomycetes), indicating that Glomales-like fungi were present at a time when the land flora most likely only consisted of plants on the bryophytic level.
Abstract: Fossilized fungal hyphae and spores from the Ordovician of Wisconsin (with an age of about 460 million years) strongly resemble modern arbuscular mycorrhizal fungi (Glomales, Zygomycetes). These fossils indicate that Glomales-like fungi were present at a time when the land flora most likely only consisted of plants on the bryophytic level. Thus, these fungi may have played a crucial role in facilitating the colonization of land by plants, and the fossils support molecular estimates of fungal phylogeny that place the origin of the major groups of terrestrial fungi (Ascomycota, Basidiomycota, and Glomales) around 600 million years ago.

1,045 citations