Figure 1 - uploaded by Nicholas B. Sullivan
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b-Geologic map of upstate New York with Medina, Clinton, Lockport, and Salina/Bertie Groups highlighted (modified from Fisher et al., 1970). The outcrops featured in this excursion are located in Oneida County, which is outlined in black on this map.
Source publication
The fossiliferous and oolitic ironstones of the Clinton Group (Silurian, late Llandovery to early Wenlock) in central New York have inspired considerable interest since the early surveys of Eaton in the 1820s. Although these ores have never been mined on industrial scales, they were processed extensively up to the mid 1900s for oxides used in red p...
Context in source publication
Context 1
... of this bedrock is contained within the Appalachian Foreland Basin, a large structural and depositional province bounded by the Cincinnati, Findlay, and Algonquin Arches to the west and the Appalachian Highlands to the east (Figure 1a; Colton, 1970). In central and western New York, Silurian strata are exposed along a roughly east-west trending outcrop belt, running between Niagara and Schoharie Counties (Figure 1b), which marks the northern margin of the Appalachian Foreland Basin. ...
Citations
... One long held consensus was that Fe was sourced from weathering of Brett et al. (1990bBrett et al. ( , 1998 and ages are as presented in McLaughlin et al. (2012) and Sullivan et al. (2012). SB = Sequence Boundary. ...
... C) Cross section as in Panel A with shading indicating the Clinton subdivisions and Sequences II-V of Brett et al. (1998). In Panels A and C, the cross section west of Oneida County is based on that of Sullivan et al. (2012), originally modified after Gillette (1947) and Brett et al. (1998). Oneida County is based off of the aforementioned references, slightly modified based on the work presented herein. ...
... In the last three decades, there has been an evolution of thought away from the shallow shoal model. Brett et al. (1990bBrett et al. ( , 1998 put the ironstones into regional litho-and sequence stratigraphic contexts, demonstrating that they occur at discrete horizons in the succession (largely flooding surfaces) associated with sediment starvation ( Fig. 6; also proposed or supported by Castano and Garrels, 1950;Hunter, 1960;Berman, 1963;Lin and Brett, 1988;Bayer, 1989;McLaughlin et al., 2008;Sullivan et al., 2012;Chowns and Rindsberg, 2015). Concurrently, there was increasing attribution of ironstone genesis to authigenic Fe mineral precipitation in which Fe minerals precipitate as concretions or cements in the shallow subsurface across a wide range of water depths and were not necessarily tied to a shallow-marine terrestrial Fe source (Alling, 1947;Schoen, 1962;Cotter and Link, 1993;Brett et al., 1998;McLaughlin et al., 2012;Sullivan et al., 2012;Sullivan and Brett, 2013). ...
Ironstone is a marine biochemical sedimentary rock with syndepositional Fe enrichment that has long been viewed as a geologic curio. It is widespread in the Silurian Clinton Group and coeval strata across the Appalachian Foreland Basin (the “Clinton ironstones”), where it has been the focus of extensive historical study aimed at elucidating its enigmatic origin. Recent interpretation of early Paleozoic ironstone as the consequence of upwelling directly tied to ocean circulation provides the impetus to reinvestigate the global significance of the Clinton ironstones. To achieve this, review of 175 years of literature is combined with detailed sedimentologic, stratigraphic, and petrographic reinvestigation of the Clinton ironstone in its type area of New York State. Results are interpreted in the context of modern understanding of the Fe biogeochemical cycle and early Paleozoic Earth system. Two distinct ironstone types exist. Granular ironstone contains Fe coated grains with quartz sand nuclei. Fossiliferous ironstone contains calcareous skeletal grains with Fe mineral coatings and cements. Fe minerals in both are predominantly hematite with subordinate chamosite. Ironstone is found in discrete time-specific stratigraphic units that alternate with siliciclastic facies interpreted as accumulating in fluvial to storm wave base environments. Most ironstone formed during transgression as the indirect result of upwelling of ferruginous deep water off the Laurentian margin. Supply of this water into the Appalachian Foreland Basin led to ironstone genesis where ferruginous and shallow oxygenated waters mixed; this zone generally stretched from storm wave base to the lower shoreface. Particulate ferric oxyhydroxide that precipitated in this zone accumulated across an otherwise sediment starved seafloor during transgression. Its burial and subsequent reduction formed a zone of authigenic Fe oxyhydroxide and silicate precipitation within a few decimeters of the seafloor. The complete ferruginization of beds was the result of movement of the zone of precipitation combined with periods of exhumation and reworking. The cyclicity of the Clinton ironstones records discrete periods of ferruginous water upwelling and/or incursion. These periods correlate with Silurian marine biodiversity crises, notably the Ireviken Event. The depositional model presented herein supports that carbon cycle perturbations and extinction events such as the Ireviken were caused by the expansion of anoxic and euxinic conditions on continental shelves, the direct product of increased upwelling of anoxic basinal waters that were also the source of the Fe in the Clinton and other early Paleozoic upwelling-associated ironstone. Review of the Clinton ironstones in light of both the increased understanding of ironstone and the refined view of early Paleozoic atmospheric, oceanic, and biotic perturbations thus suggests that ironstone is an underutilized proxy of oceanic and biotic instability in the early Paleozoic Earth system.
... ning characteristics of these rocks: fine sand grains (usually quartz) surrounded by concentric rings of hematite, chamosite, and silica embedded in a carbonate matrix (Smyth, 1892; Schoen, 1962). The purpose of this study is to re-examine samples of this unusual rock collected from the type locality using modern analytical tools (SEM/EDS, WD-XRF). Sullivan et al. (2012)). B) Sample site (CH-2) of Kirkland Iron Ore and sedimentary rocks overlying and underlying the hematite layer at Sherman Brook (Dawes Quarry Creek). C) Sample site (CH-3) of Westmoreland Iron Ore and sedimentary rocks overlying and underlying the hematite layer at Sherman Brook (Dawes Quarry Creek). In June 2015 I went to two of the be ...
... The Kirkland Iron Ore ranges in thickness, reaching up to 2 meters in Lairdsville, NY. It is composed of crinoid-dominated packstones and fossiliferous hematitic grainstone, and is characterized by high concentrations of carbonate and several cross-stratified horizons indicative of moderate to high energy transgressive shoal conditions and shallow water (Sullivan, et al., 2012). We examined 5 samples of the Kirkland Iron Ore and observed the following features. ...
... Some sections of this unit contain a thin tongue of grey shale which may contain brachiopods and graptolites. (Sullivan, et al., 2012). We examined 4 samples of the Westmoreland Iron Ore and observed the following features. ...
Oolitic ironstones were once an important source of iron, providing much of our country’s iron from Colonial times up through the early 20th century. While no longer economically important, these unique rocks provide a record of an unusual, and still poorly understood, depositional marine environment. Previous studies documented the defining characteristics of these rocks: fine sand grains (usually quartz) surrounded by concentric rings of hematite, chamosite, and silica embedded in a carbonate matrix (Smyth, 1892; Schoen, 1962). The purpose of this study was to re-examine samples of this unusual rock collected from the type locality using modern analytical tools (SEM/EDS, WD-XRF).
We collected samples of the two major hematite beds (the Westmoreland and Kirkland) along with samples of the surrounding lithologies of the Silurian Clinton Group from exposures along Sherman Brook in the town of Kirkland. Our studies confirmed that most of the ooids are small rounded quartz grains surrounded by rings of hematite, silica, and chamosite cemented together by a matrix of dolomite. In some samples, however, many of the ooids contain bands of calcium phosphate. While the presence of phosphorous had been previously noted in the bulk chemical analysis of the ore (up to 2.5 wt. % P2O5)(Newland & Hartnagel, 1908), and in the presence of small angular clasts of apatite (presumably bone or shell fragments) (Schoen, 1962), it had not previously been reported in the ooids themselves.
Our studies also revealed that the matrix consists of two compositionally distinct varieties of ferroan dolomite, along with hematite, chamosite, and small (< 50 um) grains of detrital zircon, rutile, and chromite. Some ironstone beds contain relatively high concentrations of zircon, making them ideal candidates for sediment provenance studies. Calcite is a minor cement, and is commonly found in thin, cross-cutting veins.
The ironstones appear to have formed in a shallow marine environment with very limited input of mature clastic sediment. Ooids with alternating concentric bands of silica, apatite, hematite and chamosite (or their precursors, goethite and berthierine), require a very unusual marine environment with rapidly shifting conditions for the precipitation / formation of these four phases.
... Locations of samples in British Columbia and Alberta, Canada (A) and in Vermont and New York, U.S.A. (B).Table 1shows the group, formation and lithology of these samples. Diagram modified fromActon et al. (2000),Coleman (1988),Desjardins et al. (2010),Fyles (1967),Hatch et al. (1988),Ruks et al. (2010) andSullivan et al. (2012). this article in press as:Chalmers, G.R.L., Bustin, R.M. Porosity and pore size distribution of deeply-buried fine-grained rocks: Influence of diagenetic and metamorphic processes on shale reservoir quality and exploration. ...
Significant exploration risks are associated with the pursuit of deeply-buried shale gas reservoirs due to pore volume reduction and changes in pore size distribution. These changes in pore character result in decreases in gas in place and permeability. A suite of shale, low grade, pelitic metamorphic and a granite outcrop samples from various location in North America have been selected to span the later stages of diagenetic, epimetamorphic (epizone) and anchimetamorphic (anchizone) processes to evaluate the changes in the inorganic pore volumes and size distributions. Diagenetic/metamorphic ranking of samples were determined by the illite crystallinity method. Pore volumes reduce with increasing maturity/metamorphic grade. The loss of mesopore volume (2-50 nm) with increasing maturity is the cause of the reduction in porosity. The reduction in mesopore volume is interpreted to be due to the authigenic recrystallization and growth of the clay minerals. As maturity/metamorphic grade increases there is a relative increase in the macropore (>50 nm) and micropore (<2 nm) size fractions. The increase in micropore volumes may be attributed to the development of secondary porosity within the kerogen. At higher maturity/metamorphic grade (i.e.; illite crystallinity < 0.2 Δ2θ) porosity values range between 0.9% and 3.6% indicating that fracture porosity is not the only mechanism of gas storage in deeply buried shale (and pelitic metamorphic rocks) reservoirs. Matrix porosities in these higher maturity/metamorphic samples are comparable to matrix porosities of the Horn River shales of British Columbia and other shale reservoirs. Similar to the Horn River and Doig-Montney shales, the reduction in mesopore volumes may reduce the matrix permeability of these rocks and fracture stimulation will be an integral component of the completions program to access hydrocarbons.
... They are currently included in the Sequatchie Formation (Martin, 1992a(Martin, , 1992bDorsch and Driese, 1995). Similar facies have been described from the ironstones of New York (Alling, 1947;Hunter, 1970;Sullivan et al., 2012) and also in ferruginous sandstones of the Clinch and Tuscarora formations in Tennessee, Virginia, and Pennsylvania (Folk, 1960;Cotter, 1983;Cotter and Link, 1993;Driese et al., 1991;Castle, 1998). ...
The Red Mountain Formation is an unconformity-bounded unit including all Silurian strata in the Appalachian Valley and Ridge Province of Alabama and Georgia. It is also host to the well-known Birmingham iron-ore field. The formation is divided by paraconformities into six members that generally coincide with depositional sequences. From biostratigraphy the lower four members are established as Llandoverian: Taylor Ridge (Rhuddanian), Duck Springs (? early Aeronian), Birmingham (middle Aeronian-early Telychian), Ruffner (late Telychian). Upper members are: Rocky Row (Wenlockian) and Sparks Gap (Pridolian). Facies indicate deposition on a storm-dominated shelf with coarse grained, cross-bedded sandstone in the shoreface passing seaward into hummocky cross-bedded sandstone and shale on the inner shelf, and interbedded shale and graded sandstone or limestone (storm beds) on the outer shelf. Unless truncated by erosion, all Llandoverian sequences consist of thin retrogradational facies successions in TSTs and thick progradational successions in HSTs. Accommodation on the shelf was provided by a combination of flexural subsidence, driven by tectonic loading of the Appalachian orogen during waning stages of the Taconic orogeny and glacial eustasy. It is possible to recognize similar lithofacies and sequences at least as far north as New York State.
Coarse-grained, ferruginous, cross-bedded sandstones (ironstones) occur as sharp-based, shoreface facies associated with sequence boundaries; at the base of the TST, or making up the LST or FSST. Such shoreface deposits are commonly highly condensed with ooids of hematite-chamosite and skeletal debris coated and replaced by hematite. Mineralization was evidently favored by periods of sediment starvation and reworking on wave (TST) and tidal (LST) ravinement surfaces. However, the richest ores in the Birmingham district (Big and Irondale seams) developed in a FSST apparently as a consequence of meteoric diagenesis during forced regression.
The term “condensation” has been used in sedimentological research for 180 years and ever since the last 80 years, its interpretation has become increasingly diverse and, to a certain degree, also divergent. The result is that today, the different definitions are not always compatible and therefore useful. It is for this reason that the term “condensation” is newly defined here, using the original descriptions from before 1930 and a new interpretation of condensed sediments, which were the subject of the first monograph dedicated to condensation (Heim and Seitz, 1934).
