00640nas a2200157 4500008004100000245009900041210006900140260006900209300001200278653001200290100001800302700002100320700001300341700001300354856011500367 2009 eng d00aUpper Ordovician Trenton-Black River Hydrothermal Dolomite Reservoirs of Eastern North America0 aUpper Ordovician TrentonBlack River Hydrothermal Dolomite Reserv aCarlsbad, New MexicobNational Cave and Karst Research Institute a157-18210ageology1 aSmith, L., B.1 aStafford, K., W.1 aLand, L.1 aVeni, G. uhttps://www.nysm.nysed.gov/staff-publications/upper-ordovician-trentonblack-river-hydrothermal-dolomite-reserv01859nas a2200157 4500008004100000245012600041210006900167300001400236490000700250520132800257653002201585653001301607653002101620100001801641856004201659 2006 eng d00aOrigin and Reservoir Characteristics of Upper Ordovician Trenton-Black River Hydrothermal Dolomite Reservoirs in New York0 aOrigin and Reservoir Characteristics of Upper Ordovician Trenton a1691-17180 v903 a

In the past decade, more than 20 new natural gas fields have been discovered in laterally discontinuous dolomites of the Upper Ordovician Black River Group in south-central New York. The dolomites form around basement-rooted wrench faults that are detectable on seismic data. Most fields occur in and around elongate fault-bounded structural lows interpreted to be negative flower structures. Away from these faults, the formation is composed of impermeable limestone and forms the lateral seal for the reservoirs. In most cases, the faults die out within the overlying Trenton Limestone and Utica Shale. Most porosity occurs in saddle dolomite-coated vugs, breccias, and fractured zones. Matrix porosity is uncommon in the Black River cores described for this study.

The patchy distribution around basement-rooted faults and geochemical and fluid-inclusion analyses supports a fault-related hydrothermal origin for the saddle and matrix dolomites. This play went for many years without detection because of its unconventional structural setting (i.e., structural lows versus highs). Using the appropriate integrated structural-stratigraphic-diagenetic model, more hydrothermal dolomite natural gas reservoirs are likely to be discovered in the Black River of New York and in carbonates around the world.

10aBlack River Group10aNew York10aUpper Ordovician1 aSmith, L., B. uhttp://dx.doi.org/10.1306/0426060507801345nas a2200157 4500008004100000245009000041210006900131300001400200490000700214520084100221653002001062653002801082100001801110700001701128856004201145 2006 eng d00aStructurally Controlled Hydrothermal Alteration of Carbonate Reservoirs: Introduction0 aStructurally Controlled Hydrothermal Alteration of Carbonate Res a1635-16400 v903 a

This issue of the AAPG Bulletin is dedicated to structurally controlled hydrothermal alteration of carbonate rocks and reservoirs. This type of alteration covers the spectrum of carbonate-hosted sulfide ore deposits to hydrothermal dolomite to leached limestones, and in many cases has a major impact on reservoir type, geometry, quality, and distribution. Hydrothermal dolomite (HTD) reservoirs have a long history of exploration and development in North America, extending from the earliest discoveries in the Ordovician Lima- Indiana and other trends of the northeastern United States (Hurley and Budros, 1990; Wickstrom et al., 1992), and continuing today
with the Trenton–Black River play and other hosts in the Michigan and northern Appalachian basins of the northeastern United States
and eastern Canada.

10acarbonate rocks10aHydrothermal alteration1 aSmith, L., B.1 aDavies, G.R. uhttp://dx.doi.org/10.1306/intro90110600541nas a2200157 4500008004100000245012000041210006900161300001400230490000700244653001200251100001800263700001900281700002200300700001800322856004300340 2003 eng d00aDiscrimination of Effective from Ineffective Porosity in Heterogeneous Cretaceous Carbonates, Al Ghubar Field, Oman0 aDiscrimination of Effective from Ineffective Porosity in Heterog a1509-15290 v8710ageology1 aSmith, L., B.1 aEberli, G., P.1 aMasaferro, J., L.1 aAl-Dhahab, S. uhttp://dx.doi.org/10.1306/04170320018000568nas a2200145 4500008004100000245011400041210006900155300001200224490000700236653001200243100001800255700001900273700001900292856011100311 2003 eng d00aIntegrated Characterization of Hydrothermal Dolomite Reservoirs in Trenton-Black River Carbonates of New York0 aIntegrated Characterization of Hydrothermal Dolomite Reservoirs  a254-2550 v2510ageology1 aSmith, L., B.1 aLugurt, C., M.1 aNyahay, R., E. uhttps://www.nysm.nysed.gov/staff-publications/integrated-characterization-hydrothermal-dolomite-reservoirs03935nas a2200193 4500008004100000245010400041210006900145300001300214490000700227520330300234653001203537653001903549653001403568653001003582653005703592100001803649700001703667856005703684 2001 eng d00aDiscrimination of Local and Global Effects on Upper Mississippian Stratigraphy, Illinois Basin, USA0 aDiscrimination of Local and Global Effects on Upper Mississippia a985-10020 v713 a

Interpretive cross sections based on detailed descriptions of 33 outcrops and cores are used to better understand the relative effects of tectonics, eustasy, tides, and climate on Upper Mississippian (middle Chesterian) stratigraphy in the tectonically active, tide-dominated Illinois basin. The cross sections show that five mixed carbonate-siliciclastic, high-frequency sequences in the Bethel through Glen Dean formations can be correlated around the outcrop belt through areas with very different subsidence histories.

The sequence boundaries are marked by paleosols and incised valleys and can be correlated basin-wide within a framework of distinctive marker beds. Because of its updip position, lowstand systems tracts are not preserved in the Illinois basin. The transgressive systems tracts generally consist of one or two parasequences that are typically composed of tidally influenced quartz sandstone filling incised valleys at the base overlain by open-marine skeletal limestone, shallow-marine shale, and heterolithic siliciclastic tidal-flat deposits. The maximum flooding surface (MFS) for the sequences is picked at the base of the deepest water limestone facies. Highstand systems tracts are composed of 1 to 6 regressive parasequences that consist of basal offshore skeletal limestone capped by laterally extensive shale and heterolithic siliciclastic tidal-flat facies.

The basin-wide extent of the sequence boundaries and maximum flooding surfaces across tectonic highs and lows suggests that the sequences were produced by eustatic sea-level changes rather than local tectonics or autogenic processes. The sequences were likely produced by moderate- to high-amplitude (30-100 m) fourth-order (∼ 400 ky) glacio-eustatic sea-level changes driven by the transition from the greenhouse conditions of the Early Mississippian to the "icehouse" conditions of the late Paleozoic. The lateral extent and frequency of component parasequences suggests that they were likely produced by fifth-order sea-level changes (10-100 ky). The sequences may be bundled into third-order composite sequences, but the third-order signal is obscured by the magnitude of the fourth-order sea-level changes a feature typical of ice-house stratigraphies.

The sequences can be used as time slices to identify spatial and temporal variations in differential subsidence between the Cincinnati Arch and the more rapidly subsiding Basin Interior. Episodes of high and low differential subsidence occurred every two to three sequences. These subsidence variations had a major impact on lithofacies distribution and onlap and offlap geometries in sequences and parasequences. The occurrence of some widespread seismically disturbed beds suggests that active faulting occurred during deposition. Normal faulting appears to have occurred during periods of high differential subsidence and reverse faulting during periods of low differential subsidence. Differential subsidence and related normal and reverse faulting may have occurred in response to phases of thrust loading and quiescence in the Appalachian orogenic belt to the east. Even in this tectonically active setting, however, it is the eustatic signal that generates basin-wide, mappable stratigraphic sequences.

10aeustasy10aIllinois basin10atectonics10atides10aUpper Mississippian (middle Chesterian) stratigraphy1 aSmith, L., B.1 aRead, J., F. uhttp://jsedres.sepmonline.org/content/71/6/985.short02779nas a2200193 4500008004100000245012200041210006900163260002600232300001200258520209600270653001202366100001802378700002102396700001702417700001802434700001902452700001802471856009602489 2001 eng d00aHigh-resolution Sequence Stratigraphic Setting of Mississippian Carbonate Eolianites, Illinois and Appalachian Basins0 aHighresolution Sequence Stratigraphic Setting of Mississippian C aTulsa, OklahomabSEPM a167-1823 a

Carbonate eolianites areabundant in the lower Chesterian Upper Mississippian succession in the Appalachian and Illinois
Basins The eolianites arequartz peloid grainstones composed of well rounded very fine to fine sand size peloids wholeooids broken
ooids that have been re rounded skeletal fragments and generally finer grained subangular frosted quartz Eolian deposits are I to 8
m thick and tens of meters to many kilometers wide They have wedge sets of planar and tangential sharply defined inverse graded
laminae with dips of up to 20 degrees.
A high resolution sequence stratigraphic framework was generated using the available biostratigraphy and closely spaced strati
graphic sections and core and tracing regional disconformities marked by breccia calcrete and soil horizons between the sections
EolianiIe units backstep within the transgressive part of the Chesterian supersequence and are absent from the highstand part which is dominated by siliciclasticsand likely formed in a more humid setting Withinthird order and fourth order sequences the eolianites occur updip in disconformity bounded parasequences In the transgressive and early highstand systems tracts of sequences eolianiIes overlie exposure surfaces and are preserved in the transgressive parts of the parasequences In the late highstand parts of sequences eolianites are preserved in the regressive parts of parasequences and are capped by sequence bounding disconformities marked by breccia and calcrete.
The abundance of carbonaIe eolianiIes in the Upper Mississippian is likely due to seasonal semiarid climate and moderate amplitude
fourth order eustatic sea level changes The reservoir potential of the eolianites is limited by tight packing and calcite cementation
However recognition of the eolianites is critical to understanding the vertical and lateral distribution of reservoir facies within the
sequence stratigraphic framework because they indicate subaerial conditions and commonly mark subtle sequence boundaries.

10ageology1 aSmith, L., B.1 aAl-Tawil, A., A.1 aRead, J., F.1 aAbegg, F., A.1 aHarris, P., M.1 aLoope, D., B. uhttp://archives.datapages.com/data/sepm_sp/SP71/High-Resolution_Sequence_Stratigraphic.html02138nas a2200181 4500008004100000245013400041210006900175300001200244490000700256520150200263653001201765653003001777653003401807653002601841100001801867700001701885856005401902 2000 eng d00aRapid Onset of Late Paleozoic Glaciation on Gondwana: Evidence from Upper Mississippian Strata of the Midcontinent, United States0 aRapid Onset of Late Paleozoic Glaciation on Gondwana Evidence fr a279-2820 v283 a

Direct evidence of the late Paleozoic glaciation of Gondwana from glacial deposits suggests that geographically extensive continental glaciation began some time in the Namurian (Late Mississippian). However, the timing and characteristics of the onset of glaciation are poorly understood because of a lack of reliable paleontological control and reworking of initial glacial deposits by subsequent glacial advances. Indirect evidence of glaciation preserved in unconformity-bounded, low-latitude ramp sequences in the Illinois basin, United States, suggests that geographically extensive continental glaciation of Gondwana actually began in the late Visean. An abrupt change from carbonate-dominated sequences bounded by disconformities with little evidence of erosion to mixed carbonate-siliciclastic sequences bounded by unconformities with deep incised valleys was likely produced by a three-fold increase in the magnitude of eustatic sea-level fluctuations. The increase in the magnitude of sea-level fluctuations was likely driven by an equally abrupt increase in ice volume and marks the onset of the geographically extensive late Paleozoic glaciation of Gondwana. A possible explanation for the rapid onset of glaciation is the closing of the equatorial seaway between Laurussia and Gondwana. Closing of this seaway would have led to an abrupt change in oceanic and atmospheric circulation patterns that could have initiated major continental glaciation in the Southern Hemisphere.

10aeustasy10aincised valley glaciation10amixed carbonate-siliciclastic10asequence stratigraphy1 aSmith, L., B.1 aRead, J., F. uhttp://geology.gsapubs.org/content/28/3/279.short