PRELIMINARY SEQUENCE AND EVENT STRATIGRAPHIC CORRELATIONS WITHIN THE HELDERBERG GROUP (SILURIAN-DEVONIAN) BETWEEN NEW YORK AND THE CENTRAL APPALACHIAN.

PRELIMINARY SEQUENCE AND EVENT PRELIMINARY SEQUENCE AND EVENT STRATIGRAPHIC CORRELATIONS STRATIGRAPHIC CORRELATIONS

WITHIN THE HELDERBERG GROUP WITHIN THE HELDERBERG GROUP (SILURIAN-DEVONIAN) BETWEEN(SILURIAN-DEVONIAN) BETWEEN

NEW YORK AND THE CENTRAL NEW YORK AND THE CENTRAL APPALACHIAN BASINAPPALACHIAN BASIN

James R. EbertJames R. Ebert

Damon K. MattesonDamon K. Matteson

SUNY College at OneontaSUNY College at Oneonta

New York: Appalachian Standard SuccessionNew York: Appalachian Standard Succession

Late nineteenth and Late nineteenth and early twentieth century early twentieth century studiesstudiesJohnson and Murphy Johnson and Murphy (1969)(1969)Helderberg GroupHelderberg GroupSilurian-DevonianSilurian-Devonian– PPřídolí-Lochkovianřídolí-Lochkovian– Predominantly limestonePredominantly limestone– Some shaly unitsSome shaly units

Primacy of New YorkPrimacy of New Yorkin the Early Literaturein the Early Literature

Early Twentieth Century Stratigraphy and Early Twentieth Century Stratigraphy and Correlations to New York based on:Correlations to New York based on:– General lithologic similaritiesGeneral lithologic similarities– Faunal similaritiesFaunal similarities

Names from New York applied from New Names from New York applied from New Jersey to Virginia – the Central Jersey to Virginia – the Central Appalachian Basin (CAB)Appalachian Basin (CAB)

A New View of Helderberg StratigraphyA New View of Helderberg Stratigraphy

Rickard (1962) - migrating coeval faciesRickard (1962) - migrating coeval facies

Laporte (1969) – spectrum of ramp environmentsLaporte (1969) – spectrum of ramp environments

Rickard’s (1962) migrating coeval facies Rickard’s (1962) migrating coeval facies influences correlationsinfluences correlations– in the CABin the CAB– between NY and the CABbetween NY and the CAB

Head (1969, 1972, 1974)Head (1969, 1972, 1974)

Dorobek (1984), Dorobek and Read (1986)Dorobek (1984), Dorobek and Read (1986)

Rickard’s Stratigraphy and the Role of Rickard’s Stratigraphy and the Role of the Appalachian Standard Successionthe Appalachian Standard Succession

Revised Helderberg Stratigraphy – New YorkRevised Helderberg Stratigraphy – New YorkEbert and Matteson (2003a,b)Ebert and Matteson (2003a,b)

Rationale for Revised StratigraphyRationale for Revised Stratigraphy

Contacts are Contacts are unconformableunconformable

Clarifies placement of the Clarifies placement of the S/D boundary based on S/D boundary based on conodontsconodonts

New Questions in a Classic SettingNew Questions in a Classic Setting

How does the presence of unconformities in NY affect correlations within the CAB and between NY and the CAB?

Are these unconformities widespread? Can they be recognized in the CAB and used as a framework for correlation?

What are the relative roles of eustatic and What are the relative roles of eustatic and tectonic processes in producing the tectonic processes in producing the unconformities?unconformities?

Can basin-wide revision of Helderberg Can basin-wide revision of Helderberg stratigraphy provide new insights on global sea stratigraphy provide new insights on global sea level change around the S/D boundary?level change around the S/D boundary?

Framework for Stratigraphic CorrelationsFramework for Stratigraphic Correlations

Working model of early correlationsWorking model of early correlations

Examination of contactsExamination of contacts– Evidence of erosionEvidence of erosion– Evidence of sediment starvationEvidence of sediment starvation

Biostratigraphic data – FAD Biostratigraphic data – FAD Icriodus woschmidtiIcriodus woschmidti

Unique faunal occurrences - Unique faunal occurrences - ScyphocrinitesScyphocrinites

Recognition of events and marker bedsRecognition of events and marker beds– Distinctive facies/lithologies - twoDistinctive facies/lithologies - two– Episodes of siliciclastic influxEpisodes of siliciclastic influx– Trangressive maxima - twoTrangressive maxima - two– Bald Hill K-bentonitesBald Hill K-bentonites

New York CAB New Scotland Upper Mandata

Upper Kalkberg Bald Hill K-bentonites

Mandata Shale Bald Hill K-bentonites

? Phosphate & pyrite nodules Bald Hill K-bentonites

Kalkberg Bald Hill K-bentonites Corriganville Limestone

Punch Kill Unconformity/Black Shale Coeymans (Ravena/Deansboro) New Creek Limestone L

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Howe Cave Unconformity First Icriodus woschmidti – Silurian/Devonian Boundary

Elmwood/CR/Jamesville Upper Keyser Olney/Dayville Jersey Shore Member

Terrace Mountain Unconformity/Glauconitic limestone

Green Vedder Member Scyphocrinites

Big Mountain Shale Scyphocrinites

Clockville Discontinuity/Pyritic hardground Thacher Member Byers Island Member

Minelot Falls/Tonoloway-Keyser Unconformity Rondout – Chrysler Mbr. Tonoloway

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Cobleskill Skeletal zone in Tonoloway ?

Sequence 1: Manlius/Lower KeyserSequence 1: Manlius/Lower Keyser

New York CAB

New Scotland Upper Mandata Upper Kalkberg

Bald Hill K-bentonites Mandata Shale

Bald Hill K-bentonites ? Phosphate & pyrite nodules

Bald Hill K-bentonites Kalkberg

Bald Hill K-bentonites Corriganville Limestone

Punch Kill Unconformity/Black Shale Coeymans (Ravena/Deansboro) New Creek Limestone

First Icriodus woschmidti – S/D Boundary Howe Cave Unconformity








Sequence 2:Sequence 2:Green Vedder/Big Mountain ShaleGreen Vedder/Big Mountain Shale

New York CAB












Clockville Discontinuity/Pyritic hardground Thacher Member Byers Island Member Minelot Falls/Tonoloway-Keyser Unconformity

Rondout – Chrysler Mbr. Tonoloway Cobleskill Skeletal zone in Tonoloway ?

First Transgressive Maximum and First Transgressive Maximum and Siliciclastic-bearing UnitsSiliciclastic-bearing Units

New York CAB














Sequence 3: Dayville/U. Manlius/U. KeyserSequence 3: Dayville/U. Manlius/U. Keyser

New York CAB














Sequence 4: Coeymans/New CreekSequence 4: Coeymans/New Creek

First Icriodus woschmidti - Silurian/Devonian BoundaryHCU is erosional throughout the basin

New York CAB














Sequence 5:Kalkberg/Corriganville

New York CAB














?An Undiscovered Unconformity in NY?

New York CAB














Bald Hill K-bentonitesBald Hill K-bentonites

Age of S/D Boundary - 418 MaAge of S/D Boundary - 418 Ma(Tucker, et. al. 1998)(Tucker, et. al. 1998)

Basin-wide markersBasin-wide markers(Smith, Berkheiser and Way 1986)(Smith, Berkheiser and Way 1986)

Second Transgressive MaximumSecond Transgressive Maximum

New York CAB




















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ConclusionsConclusionsNY unconformities can be traced into CABNY unconformities can be traced into CAB

Most unconformities in NY are erosionalMost unconformities in NY are erosional

Most in the CAB are marked by sediment starvationMost in the CAB are marked by sediment starvation

Minelot Falls/Tonoloway-Keyser Unconformity and Minelot Falls/Tonoloway-Keyser Unconformity and Howe Cave Unconformity are erosional throughout Howe Cave Unconformity are erosional throughout basinbasin

A PA Přídolířídolí transgressive maximum is now recognized transgressive maximum is now recognized

Sequence and event stratigraphic correlations Sequence and event stratigraphic correlations between NY and the CAB are similar to those between NY and the CAB are similar to those proposed in the early twentieth centuryproposed in the early twentieth century

Correlations are preliminary; much more work Correlations are preliminary; much more work needs to be done!needs to be done!







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PRELIMINARY SEQUENCE AND EVENT STRATIGRAPHIC CORRELATIONS WITHIN THE HELDERBERG GROUP (SILURIAN-DEVONIAN) BETWEEN NEW YORK AND THE CENTRAL APPALACHIAN.

Documents

basin slide

oneonta slide

kalkbergcorriganville

transgressive maximum

manliuslower keyser

primacy of new york

new insights

new jersey