Warren Huff

University of Cincinnati | UC · Department of Geology

Cretaceous strata preserved in Wyoming contain numerous large bentonite deposits formed from the felsic ash of volcanic eruptions, mainly derived from Idaho batholith magmatism. These bentonites preserve a near-continuous 40 m.y. chronology of volcanism and their whole-rock and mineral chemistry has been used to document igneous processes and recon...

Volcanic centers are complex, dynamic landforms. The stunning morphological variety of volcanic landforms is due to a combination of tectonic setting, eruption style, magma composition and volume, surface environment, and age, i.e., the time the landform has existed and evolved. The considerable variety of volcanic landforms reflects the large vari...

Volcanic hazards are direct and indirect, and they encompass diverse phenomena such as pyroclastic and lava flows, poisonous-gas emissions, landslides, lahars, tsunamis, jökulhlaups, and climate change. The geomorphology of volcanic landforms and their deposits provide essential insights into the past and future volcanic hazards. Volcanic disaster...

Bentonite beds, which are clay deposits produced by the submarine alteration of volcanic tephra, preserve millions of years of volcanic products linked to mag-matic systems for which records are otherwise lost through erosion and alteration. Cretaceous strata from the Bighorn Basin, Wyoming, and southwestern South Dakota contain bentonites that ori...

The position of the Ordovician/Silurian boundary in the strata of the Appalachian basin had been questioned by Bergström and colleagues, with their discovery of elevated δC13 values (probable HICE) suggesting a Hirnantian age for the presumed Silurian, Manitoulin Fm. This study investigated this controversy through detailed fieldwork and analysis o...

Bentonite, a claystone formed from the devitrification of volcanic ash, demonstrates varying amounts of alteration in elemental concentrations through the transition from glass to clay. Many studies have sought to characterize and correlate bentonites using various elemental signatures, but the information garnered from this can be misleading since...

The Doushantuo negative carbon isotope excursion (DOUNCE) is the largest known marine inorganic carbon isotope anomaly. The origin of this pronounced negative excursion is still an enigmatic issue that attracts geologists. Time constraints on the excursion are the critical information that would provide insight into its genesis. In previous decades...

Changes in the global atmospheric budget of platinum reportedly correspond to explosive volcanic eruptions. Using inductively coupled plasma mass spectrometry (ICP-MS) elemental analysis we examined eight widely separated stratified sites to evaluate the geographic extent of three late Holocene high magnitude volcanic events. We found characteristi...

Permian-Triassic (P-Tr) altered volcanic ashes (tuffs) are widely distributed within the P-Tr boundary successions in South China. Volcanic altered ashes from terrestrial section-Chahe (CH) and marine section-Shangsi (SS) are selected to further understand the influence of sedimentary environments and volcanic sources on diagenetic alterarion on vo...

Previous studies in Chaco Canyon, New Mexico suggested that water management systems constructed during periods of increased aridity resulted in elevated salinity levels to the point that soils were no longer viable for growing cultigens. Salinity, pH, powder X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy analyses of...

Pyroclastic material in the form of altered volcanic ash or tephra has been reported and described from one or more stratigraphic units from the Proterozoic to the Tertiary. This altered tephra, variously called bentonite or K-bentonite or tonstein depending on the degree of alteration and chemical composition, is often linked to large explosive vo...

Precise determinations of the rates and durations of Palaeozoic biogeochemical events are largely unavailable. Here, we present two new high-precision U–Pb (zircon) dates from volcanic ash deposits from the Ludlow Series (Silurian System) of Podolia, Ukraine, that yielded weighted mean 206Pb/238U dates of 424.08 ± 0.20 (0.29) [0.53] Ma and 422.91 ±...

The conversion of smectite to illite has long been studied by numerous researchers because of its importance as a diagenetic metric. Interpreting the pressure, temperature, and age of the sequences in which this conversion occurs provides the possibility to identify the historical maturation parameters of hydrocarbon sources. The Black Sea Basin is...

Despite being recognized for many years, bentonites in the Guadalupian (Middle Permian Series) type area of West Texas and southeastern New Mexico have received little research attention. These important deposits offer opportunities for long dis- tance stratigraphic correlation and high-precision radioisotopic age dating. In this study, apatite phe...

The correlation of the Rader Limestone Member of the Bell Canyon Formation to its shelf equivalent has varied over the years. Some models have equated it with the Seven Rivers Formation, and others to the Yates Formation, or a position straddling both units. More recent workers have used sequence stratigraphic models to refine this shelf-to-basin c...

Precise determinations of the rates and durations of Palaeozoic biogeochemical events are largely unavailable. Here, we present two new high-precision U-Pb (zircon) dates from volcanic ash deposits from the Ludlow Series (Silurian System) of Podolia, Ukraine, that yielded weighted mean Pb-206/U-238 dates of 424.08 +/- 0.20 (0.29) [0.53] Ma and 422....

Ordovician K-bentonite beds have a long history of investigation all around the world. They have been reported from Gondwana, the Argentine Precordillera, the Yangtze Platform, Laurentia, Baltica, and numerous terrains between Gondwana and Baltica, which now constitute a part of Europe. In recent years several K-bentonite beds have also been discov...

The Lower Cambrian on the Yangtze Block in South China is valuable for understanding the early evolution of life, the global biogeochemical cycles, and the major changes of the ocean. However, both the placement of the Precambrian-Cambrian boundary in South China and the correlation of the Lower Cambrian across the Yangtze Block are still in contro...

Although known as the Meso- to Neoproterozoic Standard Section of China for more than half a century, the age of the famous Jixian Section (Jixian County, Tianjin City) has been rather poorly constrained, mainly by Rb-Sr and K-Ar ages that have proven unreliable and inaccurate in most cases. In recent years, significant progress has been made in st...

Excavation of Joachim Barrande's classic fossil locality of the "Aulacopleura shales" exposed on Na Černidlech Hill, near Loděnice reveals that most specimens were recovered from a 1.4 m interval exposed in "Barrande's pits". These are located at the eastern end of a 0.4 km trench dug in the mid 1800's to expose the interval along strike. Over an h...

Nanometric (<0.02, 0.02-0.05, 0.05-0.1, 0.1-0.2 mu m) illite fractions were separated from K-bentonite samples from northwestern Georgia, and studied by X-ray diffraction, oxygen and hydrogen isotope geochemistry, and K-Ar dated to more tightly constrain the tectono-thermal history of the Appalachian orogeny. Their XRD patterns are very similar for...

The Hazar-Madeıı Basin sediments were deposited along the southern branch of the Neotethys Ocean margin during Late Maastrichtian-Middle Eocene times. X-ray powder diffraction (XRD), ICP-AES, ICP-MS and scanning electron microscopy (SEM) were performed on samples of the Upper Maastrichtian-Middle Eocene Hazar Group and the Middle Eocene Maden Compl...

Distributions of nitrogen, boron and lithium were studied in illite–smectite from Ordovician–Silurian K-bentonites in the Baltic Basin. These trace elements are linked to thermal maturation of organic matter, creating fluid signatures that are distinct from those in regionally buried sediments. The fluid chemistry is ideally recorded in authigenic...

Volcanic centers are complex, dynamic, and continuously evolving landforms. As a consequence, volcanic landforms are highly diverse and controlled by the tectonic setting, magma type and volume, surface environment, and their age. Active volcanoes occur in most tectonic settings. Most of Earth's active volcanoes, however, are subduction-zone relate...

Siljan is Europe’s largest impact structure and preserves unique Lower Palaeozoic sedimentary successions in its ring-like depression around the central uplift. Outcrops are limited, but the Lower Palaeozoic stratigraphy investigated in three core sections provides new information revolutionizing the knowledge of the development of this area locate...

New drill cores from the largest known impact structure in Europe, the relict of the Siljan meteorite crater, provide new possibilities to reconstruct Early Palaeozoic marine environments and ecosystems, and to document changes in sedimentary facies, sea level and palaeoclimate in Baltoscandia. The impact crater is an important target of the projec...

The most extensive succession of K-bentonite beds known in the Silurian of North America occurs at Arisaig on the northern coast of Nova Scotia. At least 40 ash beds are present in the Llandoverian Ross Brook Formation and at least four in the early Ludlovian McAdam Brook Formation. Most of the beds are thin (< 5 cm), but one bed (the Smith Brook K...

Magnetization and Mössbauer spectroscopy results on aerosol processed YBa2 (Cu1-xFex)307–δ samples are presented. Systematics of Tc(x), x(x) and Fe dopant site occupancies In/I(x) as a function of dopant concentration ‘x’ are deduced and compared to those established on analogous solid-state- reacted samples. The absence of twinning in the aerosol...

Compositional variability in SiO2-Al2O3-FeO-MgO-TiO2 space as determined by microprobe analyses of biotite phenocrysts and quartz-hosted melt inclusions from four altered Ordovician tephras (the Deicke, Ragland, and Millbrig K-bentonites from eastern North America and the Kinnekulle K-bentonite from northern Europe) is compared with compositional d...

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...

Explosive eruptions from volcanoes are recorded in the stratigraphic record throughout the Phanerozoic, but evidence of these eruptions in the form of preserved tephra layers appears to be concentrated at times of active plate collision and concomitant high stands of sea level. The products of volcanic eruptions are lavas, tephra, and gases. Basalt...

Two prominent, and apparently globally distributed, δ13C excursions have been documented from the Upper Ordovician, namely the early Katian Guttenberg isotope carbon excursion (GICE) and the latest Ordovician Hirnantian isotope carbon excursion (HICE). The former excursion, which has lower δ13C values than the HICE, is now recorded from dozens of l...

The lower Silurian Osmundsberg K-bentonite is a widespread altered volcanic ash bed that occurs throughout Baltoscandia and other parts of northern Europe. K-bentonite samples from sections containing the Osmundsberg K-bentonite bed were investigated to determine whether the chemical composition of this bed is sufficiently unique and diagnostic tha...

Mixed-layer illite-smectite samples from the Ordovician and Silurian K-bentonites of the Baltic Basin and the Baltic Shield (Norway, Sweden, Denmark, Poland and Estonia) were dated by K-Ar on several grain fractions and were studied by X-ray diffraction (XRD), both on oriented and random preparations, in order to reveal the conditions of smectite i...

Crystal size distribution (CSD) analysis has been applied to quartz crystals of the Ordovician Millbrig K-bentonite, which represents one of the largest known fallout ash deposits in the Phanerozoic Era, to establish crystal growth histories and conditions in the magma chamber prior to eruption. Specific CSDs were examined for crystal growth condit...

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. Bentoni...

The K-bentonite, black shale and flysch successions at the Ordovician–Silurian transition in South China have been the subject of comprehensive investigations relative to the probable accretion of the Yangtze Block and the questionable Cathaysia Block. First, the geochemical analyses of K-bentonites show that the parent magma originated in syn-coll...

In 1556, Agricola published the first detailed description of a mudstone posthumously, but it was not until 1747 that one of them (a black shale) was formally defined by William Hooson. A review of the world literature since Hooson's time shows a slow, steady activity in the study of mudstones in the 1800s, a sharp break to more frequent activity i...

We report SHRIMP U–Pb zircon ages from K-bentonite beds from different locations in the Xiamaling Formation near Beijing at the northern margin of the North China Craton (NCC). The 1379 ± 12 Ma and 1380 ± 36 Ma ages obtained in our study correlate with similar data (1368 ± 12 Ma) obtained from recent studies and assign a Mid-Mesoproterozoic (Ectasi...

Radio-isotopic analysis of single zircons from two early Telychian K-bentonites, one of which is among the most widespread Lower Paleozoic volcanic ash falls in northern Europe, yields overlapping weighted mean 206Pb/238U ages of 438.7 ± 1.0 Ma and 437.8 ± 0.5 Ma, respectively. The former age is from zircons of the Osmundsberg K-bentonite from the...

Modulated differential scanning calorimetry measurements on bulk (Na(2)O)(x)(GeO(2))(1-x) glasses show a sharp reversibility window in the 14%<x<19% soda range, which correlates well with a broad global minimum in molar volumes. Raman and IR reflectance transverse- and longitudinal-optic mode frequencies exhibit anomalies between x(c)(1) = 14% (str...

Intermediate phases have been observed in covalent glasses, but ionically bonded network systems have received much less attention in this respect. We have now examined titled glasses in m-DSC, Raman scattering, IR reflectance and Birefringence experiments over wide range of soda concentration, 3 < x < 30%. Thermal experiments reveal a sharp revers...

Prominent Upper Ordovician K-bentonites include the Deicke and Millbrig beds in the Late Ordovician of eastern North America and the Kinnekulle K-bentonite in the uppermost Sandbian of Baltoscandia. These beds are thought to represent some of the largest ash fall deposits known in the Phanerozoic record. This report presents a comprehensive study o...

The Global Boundary Stratotype Section and Point (GSSP) for the Katian Stage of the Upper Ordovician Series is defined as the 4.0 m-level above the base of the Bigfork Chert in the Black Knob Ridge section, southeastern Oklahoma. This point in this section is coincident with the first appearance of the graptolite Diplacanthograptus caudatus, which...

Review of lithostratigraphic criteria for subdividing the Wufeng (Ordovician) and Longmaxi (Silurian) formations reaffirms their integrity and subdivisions and provides new regional correlations between the formations and related stratigraphic successions and facies. Both the black shales and the related overlying flysch deposits and other successi...

It is known that high-quality, black-shale source rocks occur in the uppermost Ordovician Wufeng Formation and in the lowermost Silurian Longmaxi Formation in South China. Hence, it is important to understand their lithostratigraphy and the controls on their deposition. A review of lithostratigraphic criteria for subdividing the two adjacent format...

The lower Pierre Shale consists primarily of the Sharon Springs Formation, which has been correlated regionally throughout Kansas, Colorado, Nebraska, Wyoming, South Dakota, and North Dakota. The unit represents distal sedimentation in a tectonically active foreland basin. Correlation of the lower Pierre Shale Group is complicated by the applicatio...

A total of 97 K-bentonite levels have been recorded from the Upper Ordovician (Ashgill) to Lower Devonian (Lochkov) sequences of the Carnic Alps, Austria. They occur in shallow to deep-water fossil-ferous marine sediments. The faunal elements suggest a plate movement from a moderately cold environment of approximately 50°S latitude in the Upper Ord...

Explosive eruptions from volcanoes are recorded in the stratigraphic record throughout the Phanerozoic. The most visible evidence of these eruptions is generally in the form of preserved tephra layers, and they appear to be concentrated in the stratigraphic record at times of active plate collision and concomitant high stands of sea level. The prod...

At least twenty silicified volcanic ash beds have been identified in the Kuibis and Schwarzrand subgroups of the terminal Proterozoic Nama Group of Namibia. Nineteen of the Nama ash beds are in the Schwarzrand Subgroup in the Witputs subbasin. Two of these are in the siliciclastic-dominated lower part of the subgroup, which consists of the Nudaus F...

Abstract Explosive volcanic activity is recorded in the Upper Jurassic of the Paris Basin and the Subalpine Basin of France by the identification of five bentonite horizons. These layers occur in Lower Oxfordian (cordatum ammonite zone) to Middle Oxfordian (plicatilis zone) clays and silty clays deposited in outer platform environments. In the Pari...

The Sebree Trough is a relatively narrow, shale-filled sedimentary feature extending for several hundred kilometers across the Middle and Late Ordovician carbonate platform of the Midcontinent United States. The dark graptolitic shales within the trough stand in contrast to the coeval bryozoan-brachiopod-echinodermrich limestones on the flanking pl...

Several Ordovician K-bentonites occurring widely in eastern North America and western Europe were dated using the 40Ar/39Ar technique to test previously suggested inter-continental correlations. The three thickest and most widespread bentonites – Deicke, Millbrig (North America) and Kinnekulle (Sweden and Denmark) – were examined. Single-grain anal...

Coping with information technology (IT) planning is one of the more important, expensive, time-consuming and potentially disastrous exercises an academic institution can undertake. Those institutions that are successful in establishing administrative and academic frameworks within which rapid technological change and adaptation can occur will survi...

The Dnestr Basin of Podolia, Ukraine, is an epicratonic basin consisting of neritic carbonate and calcareous mudstone facies including a nearly complete Silurian sequence ranging from late Llandovery to late Pridoli in age. The Silurian section has served as a standard for regional and interregional studies as a consequence of its well-documented m...