detailed sedimentology and inorganic geochemistry of the
TRANSCRIPT
Detailed Sedimentology and Inorganic Geochemistry of the Dolgeville Formation and Utica
Group of the Central Mohawk Valley, NY
Daniel Miserendino
Jeffrey T. Pietras
Introduction and Purpose
• Drill cores present continuous, unweathered rock record ideal for detailed sedimentologic and geochemical studies
• Utica Group (Indian Castle Shale and Flat Creek Shale)
• Trenton Group (Dolgeville Fm.) • Study the evolution of Ordovician foreland basin
by investigating: • Source terrain • Seawater chemistry • Sea level changes • Depositional processes • Tectonic processes
Geologic Setting
http://www.mcz.harvard.edu/Departments/InvertPaleo/Trenton/
Early Ordovician: Passive margin off southwest Laurentia formed.
Mid-Late Ordovician: Carbonate platform developed. Onset of Taconic Orogeny.
Study Area N
150 km
Legend: Core Location Major city
N
30 km
75NY-5
75NY-7
74NY-5 75NY-2 Mohawk River
Stratigraphy
modified from Brett and Baird, 2002
Stratigraphy -This Study
-Spiegel, expected 2016
-Jones, 2013
-Saboda and Lash, 2014
modified from Brett and Baird, 2002
0
100
200
300
400
500
600
700
De
pth
(ft
)
Indian Castle Shale
Lower Indian Castle Shale
Upper Indian Castle Shale
Honey Hill Disconformity
Flat Creek Shale
Dolgeville Fm.
Dolgeville Fm.
Thruway Disconformity
75NY-7 74NY-5
Wintergreen Park Interval
75NY-7
Collected near Honey Hill Rd, Newport, NY
Trenton Group Limestone
25 km
E. Spiegel
74NY-5 0.5 mm
G. Baird
Dolgeville Formation Interbedded limestone and black mudstone
Interpretation: • Alternating
turbidites and low energy, pelagic mud deposition
Near County Home, NY Core 75NY-7
.5 f
t E. Spiegel E. Spiegel
Utica Group
Dino-Lite Edge Digital Microscope
Black mudstone
Interpretation: • Low energy • Pelagic • Organic matter accumulation and pyrite
Banded black mudstone
Interpretation: • Thin turbidites • Change in pelagic sediment
Graded gray calcareous silty mudstone
1 in
Fining upwards
5 mm
Interpretation: • Turbidites
Black mudstone
Fining upwards
Black mudstone
74NY-5 75NY-7
Cross-stratified calcareous silty mudstone
5 mm 5 mm
Interpretation: • Turbidites • Contourites
Dark gray silty mudstone
Interpretation: • Increased silt and sand input • More siliciclastic input, less carbonates
Matrix supported sandy mudstone
1 in
Stratigraphic up
75NY-7
Interpretation: • Debrite
Facies Summary:
Indian Castle Shale
Flat Creek Shale
Dolgeville Fm.
75NY-7
74NY-5
Wintergreen Park Interval
Lower Indian Castle Shale
Upper Indian Castle Shale
Dolgeville Fm.
Trenton Group Limestone
• Cross-stratified calcareous silty mudstone •Graded gray calcareous silty mudstone • Black mudstone
• Black mudstone •Banded black mudstone •Graded gray calcareous silty mudstone • Cross-stratified calcareous silty mudstone •Matrix supported sandy mudstone
•Black mudstone • Banded black mudstone •Graded gray calcareous silty mudstone •Dark gray silty mudstone •Matrix supported sandy mudstone
• Black mudstone • Banded black mudstone
15
0 f
t
Depositional Summary:
Indian Castle Shale
Flat Creek Shale
Dolgeville Fm.
75NY-7
74NY-5
Wintergreen Park Interval
Lower Indian Castle Shale
Upper Indian Castle Shale
Dolgeville Fm.
Trenton Group Limestone
• Turbidites • Pelagic
• Pelagic • Turbidites (calcareous) •Debrites
• Pelagic
• Pelagic • Turbidites (calcareous, siliciclastic) •Debrites
15
0 f
t
XRF and Rock Hardness Settings Mg to Mn Fe to Mo
kV 15 40
µA 25 30
Other Helium Yellow Filter
Measured elements: Mg, Al, Si, P, S, K, Ca, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Pb, Se, Th, Rb, U, Sr, Y, Zr, Nb, Mo
Leeb’s Hardness: Indentation hardness measures resistance to material deformation
Bruker Tracer III pXRF
Proceq Equotip Piccolo 2
3900 samples
2800 samples
200
300
400
500
600
700
800
0 1 2 3 4 5 6
Lee
b's
Har
dn
ess
Al (wt %)
Leeb’s Hardness Crossplots
0
100
200
300
400
500
600
700
800
0 10 20 30 40 50
Lee
b's
Har
dn
ess
Ca (wt%)
Similar trend for K, Th, and Si
Soft= Clay Hard= Carbonate
Honey Hill Disconformity (96 ft)
Summary and Future Work
• Sub-centimeter lithologic description of the entire Utica Group in NY has revealed a variety of unique facies
• Pelagic deposition, turbidity currents, debris flows and possible contour currents contributed to deposition of the Utica Group and Dolgeville Fm
• Chemostratigraphy at 3-inch intervals may help elucidate cryptic, chronostratigraphic horizons such as the lower and upper Indian Castle Shale contact
• Leeb’s Hardness values have a negative correlation with Al, K, Th, and Si (clay mineral rich softer), and a positive correlation with Ca (carbonate beds harder)
Future Work: • Build stratigraphic columns to compare to XRF and hardness data • Millimeter-scale XRF analysis with core scanning table • Correlate litho- and chemostratigraphy to other cores • Investigate patterns and cyclicity in XRF data (Fourier Analysis)
Thank You Special thanks to:
Sigma Alpha Mu Foundation, for funding part of this research
Brian Slater and the NYS Museum, for helping us move cores to Binghamton
Gordon C. Baird, for general discussions and donating hand samples
Proceq, for letting us borrow the Equotip Piccolo 2 for rock hardness testing