Fluvial sedimentology and architecture of two Latest Devonian Lower Huntley Mountain Formation outcrops, north-central Pennsylvania, USA

1. Fluvial sedimentology and architecture
of two Latest Devonian Lower
Huntley Mountain Formation
Outcrops, north-central
Pennsylvania, USA
by Evan Filion
An Undergraduate Honors Thesis
Bucknell University Department of
Geology and Environmental Geosciences
Honors Committee: Drs. Ellen Chamberlin, Jeff Trop, and Kelly Bickel

2. Acknowledgements
Advisors:
● Dr. Ellen Chamberlin, Geology Dept.
● Dr. Jeff Trop, Geology Dept.
Additional Honors Council Reviewer:
● Dr. Kelly Bickel, Mathematics Dept.
Summer Research Partner:
● Matylda Zaklicki, 2020
Additional Collaborators:
● Dr. Dave Broussard, Lycoming College
● Lily Pfeiffer, University of Oklahoma
● Dr. Pierre Zippi, Biostratigraphy.com, LLC
2

3. Roadmap for Presentation
Motivation for project
Context, scope, and goals
Methods
Data and results:
● Sedimentology
● Fluvial architecture
● Channel depth
● Grain size
● River slope
Discussion and significance
QuestionsUS Rte. 15 at Blossburg South Outcrop 3

4. Two Outcrops
along US 15
Huntley Mountain Formation
River system (fluvial) deposits
The trusty subjects of this
research:
Blossburg West
(younger)
Blossburg South
(older)
4

5. Why study rocks
at the side of the
highway?
Obviously it’s fun, but why is it significant?
These outcrops inferred to be Latest Devonian
This is a very dynamic time period because:
● Acadian Orogeny 1,2
● Climate change/glaciation 3
● Freshwater vertebrate evolution, including
fin-to-limb transition (tetrapod) 4,5
5

6. Project Scope
and Goals
Document characteristics of 2 outcrops
near Blossburg, PA:
● Qualitative description of the lower
Huntley Mountain Fm.
● Quantitative reconstruction of Latest
Devonian river systems
(i.e. paleohydraulics)
Contextualize these data to interpret
environmental and basin sedimentation
processes
6

7. Geologic Setting - Appalachian Foreland Basin
Late Devonian = Acadian Orogeny
Sediments transported from
mountains through rivers to sea
A large portion of basin fill is
river deposits
Quantitative analysis of Latest
Devonian sediments is lacking
(e.g. channel depth, slope)
That’s where we come in :)
Paleogeographic map of Pennsylvania during Late Devonian
© 2013 Colorado Plateau Geosystems Inc.
7

8. River Systems - Facies Architecture
86
Avulsion

9. Geologic Setting - Outcrop Location in PA
Late Devonian strata5
9

10. Geologic Setting - Outcrop Location in PA
Spechty
Kopf Fm.
Rockwell Fm.
Late Devonian strata5
Other Devonian-Mississippian
strata
Research by Berg and
Edmunds (1979)7
Huntley Mountain Fm.:
● Gray sandstones
● Inferred transition
meandering to
braided
○ But no quantitative
data to support
10

11. Overview of Methods - Characterize Outcrops
Sedimentology:
● Measure rock properties (color, grain size, etc.)
● Stratigraphic column & lithofacies table
Facies Architecture:
● Scan outcrops to make 3D outcrop model
Terrestrial lidar scanner (TLS) GigaPan Epic Pro V
● High-resolution outcrop panoramas
● Map surfaces and facies on panoramas
11

12. Overview of Methods - Characterize Outcrops
Channel Depth:
● Measure bar surface height as proxy
Grain Size:
● Run disaggregated sample through
laser particle size analyzer
Paleoslope:
● Use median grain size and channel
depth to get slope Laser Particle Size Analyzer
12

13. Sedimentology
Facies Architecture
Grain Size
Paleochannel Depth
Paleoslope
Data and Results
13

14. Goal: characterize sedimentology with stratigraphic
column, lithofacies table, and images
Three facies categories identified:
Sedimentology of
Blossburg South and West
● Channel Facies
○ Green-gray channel bar sandstones
○ Intraforamational mudstone conglomerates
● Proximal Floodplain Facies
○ Crevasse splay sandstone/mudstone sheets
○ Massive red/green levee siltstone
● Distal Floodplain Facies
○ Red relict-bedded/fissile mudstone paleosols
○ Gray shales
Channel Facies
Distal Floodplain Facies
Proximal Floodplain
Facies
14

15. Sedimentology of
Blossburg South and West
Major upsection changes:
● Increase in channel facies proportion
● Decrease in distal floodplain proportion
● Decrease in paleosol abundance
15

16. Facies Architecture - Example of how to make and read architecture maps
Gigapan Image
Architecture
Map Overlaid on
Gigapan Image
16

17. Blossburg South
Ribbon/Sheet Sand Body
17

18. Blossburg West
Amalgamated Sand Body
18

19. Facies Architecture
Important results:
● Lateral accretion surfaces
● Facies proportion based on area
measurement:
Blossburg
South
(older)
Blossburg
West
(younger)
Blossburg
South
Blossburg
WestMajor upsection changes:
● Ribbon sand bodies → amalgamated
● Increase in channel facies proportion
19

20. Upsection Change:
● Increase in channel depth
Paleochannel Depth
Goal:
Measure the height of
bar surfaces as proxy
for channel depth
Results:
Paleochannel depths
range 0.9-2.7 m
20

21. Grain Size
Goal:
Calculate the
median grain size
(D50) of channel
bar deposits
Upsection Change:
● Increase in grain size
Results:
Valid grain size
medians range
142-221 μm
PDF grain size curve
D50 values plotted vs. stratigraphic height
(Blossburg Middle data from Zaklicki, 2020)8
21

22. Paleoslope
Goal:
Use D50 and channel
depth values → slope
(Lynds et al., 2014)9
NO significant change
in slope
Results:
Paleoslope estimates range
0.31 x10-4 - 2.7 x10-4
Method 1 slope equation
Method 2 slope equation
Method 2 slope values plotted vs.
stratigraphic height
(Blossburg Middle data from Zaklicki, 2020)8
22

23. Discussion
River Plan Form
What types of river systems built
Blossburg South and West strata?
● Low slope (~10-4)
● Fine- to medium-grained sand
○ (not coarse/v.coarse sand/gravel)
● Lateral accretion surfaces
= Meandering Rivers
23

24. Discussion - Explain Upsection Changes
Primary upsection changes:
● Increase in grain size
● Increase in channel depth
● Increase in channel facies proportion
● Decrease in distal floodplain preservation
With an unchanging slope
What could cause this?
Three variables to consider:
1. Progradation of a Distributive Fluvial
System
2. Decrease in accommodation to
sedimentation ratio
3. Climate change - including glaciation
and/or increase in precipitation
24

25. Kosi megafan distributive fluvial system, northern India
Prograding
Distributive
Fluvial System
Not well characterized in Appalachian
foreland basin, but are likely 10
25

26. Prograding
Distributive
Fluvial System
Progradation consistent with:
● Increased channel facies proportion
● Increased grain size
● Increased channel depth
Not well characterized in Appalachian
foreland basin, but are likely
Facies architecture model for prograding DFS 11
(older)
(younger)
26

27. Decreasing Accommodation-to-Sedimentation

28. Decreasing Accommodation-to-Sedimentation
28

29. Decreasing Accommodation-to-Sedimentation
Decreasing accommodation consistent with: 12,13
● Increasing channel facies proportion
● Decreasing distal floodplain preservation
○ Reworking of deposits (i.e. scouring)
High A-to-S
Low A-to-S
29
However, Columbera et al. (2015) suggests these
changes are unreliable for predicting A-to-S 14

30. View of Appalachian foreland basin during glaciation 3Age comparison for strata around glacial interval 16
Climate Change/Glaciation - Comparing Outcrop Ages
● Decreasing sea level = increasing slope?
● Glacial advance = increasing discharge = deeper channels + bigger grains?Latest Devonian age zones 30

31. Significance and
Conclusions
What have we learned from Blossburg
South and West?
First quantitative reconstruction of Latest Devonian
Appalachian landscape and rivers:
● Slope = ~0.3-2 x10-4
● Channels are generally 0.9-2.7 m deep
● Lower Huntley Mountain Fm. is ~68-75% channel deposit
○ (Nearly equivalent to sandstone proportion)
Although previous research suggests a change in river plan
form (e.g. meandering → braided river):
● Both outcrops = Meandering River (L. Huntley Mtn. Fm.)
31

32. Significance and
Conclusions
What have we learned from Blossburg
South and West?
Upsection changes could result from:
● Prograding distributive fluvial system in the alluvial plain
● The advance of glaciers and increased discharge
Further research to improve interpretations:
● Ages of more palynology samples, closely-spaced
throughout the Blossburg section - improve confidence
● Increased sample size for paleoslope estimation
● Extending the Blossburg section upward into upper
Huntley Mountain Fm.
32

33. THANK YOU!
QUESTIONS?

34. References
1) Murphy, J. B., and Keppie, J. D., 2005, The Acadian orogeny in the northern
Appalachians: International Geology Review, v. 47, no. 7, p. 663-687.
2) Bradley, D. C., and O'Sullivan, P., 2017, Detrital zircon geochronology of pre‐and
syncollisional strata, Acadian orogen, Maine Appalachians: Basin Research, v. 29,
no. 5, p. 571-590.
3) Brezinski, D. K., Cecil, C. B., and Skema, V. W., 2010, Late Devonian glacigenic
and associated facies from the central Appalachian Basin, eastern United States:
GSA Bulletin, v. 122, no. 1-2, p. 265-281.
4) Daeschler, E. B., Clack, J. A., and Shubin, N. H., 2009, Late Devonian tetrapod
remains from Red Hill, Pennsylvania, USA: how much diversity?: Acta Zoologica, 90,
p. 306-317. doi:10.1111/j.1463-6395.2008.00361.x
5) Broussard, D. R., Trop, J. M., Benowitz, J. A., Daeschler, E. B., Chamberlain Jr, J.
A., and Chamberlain, R. B., 2018, Depositional setting, taphonomy and
geochronology of new fossil sites in the Catskill Formation (Upper Devonian) of
north-central Pennsylvania, USA, including a new early tetrapod fossil:
Palaeogeography, Palaeoclimatology, Palaeoecology, v. 511, p. 168-187.
6) Chamberlin, E. P., and Hajek, E. A., 2015, Interpreting paleo-avulsion dynamics
from multistory sand bodies: Journal of Sedimentary Research, v. 85, no. 2, p. 82-94.
7) Berg, T. M., and Edmunds, W. E., 1979, The Huntley Mountain Formation: Catskill-
to-Burgoon transition in north-central Pennsylvania: Pennsylvania Geological Survey,
4th ser., Information Circular 83, 80 p.
8) Zaklicki, M.B., 2020, Sedimentological, fluvial architecture, and paleoenvironment
analysis of the Late Devonian Catskill Formation, north-central Pennsylvania, USA
[Undergraduate Honors Thesis]: Bucknell University.
34
9) Lynds, R. M., Mohrig, D., Hajek, E. A., and Heller, P. L., 2014, Paleoslope
reconstruction in sandy suspended-load-dominant rivers: Journal of Sedimentary
Research, v. 84, no. 10, p. 825-836.
10) Davidson, S. K., Hartley, A. J., Weissmann, G. S., Nichols, G. J., and Scuderi, L.
A., 2013, Geomorphic elements on modern distributive fluvial systems:
Geomorphology, v. 180, p. 82-95.
11) Weissmann, G. S., Hartley, A. J., Scuderi, L. A., Nichols, G. J., Davidson, S. K.,
Owen, A., et al., 2013, Prograding distributive fluvial systems: geomorphic models
and ancient examples, in New Frontiers in Paleopedology and Terrestrial
Paleoclimatology: SEPM Special Publication, v. 104, p. 131-147.
12) Bridge, J. S., and Leeder, M. R., 1979, A simulation model of alluvial
stratigraphy: Sedimentology, v. 26, no. 5, p. 617-644.
13) Heller, P. L., and Paola, C., 1996, Downstream changes in alluvial architecture;
an exploration of controls on channel-stacking patterns: Journal of Sedimentary
Research, v. 66, no. 2, p. 297-306.
14) Colombera, L., Mountney, N. P., and McCaffrey, W. D., 2015, A meta-study of
relationships between fluvial channel-body stacking pattern and aggradation rate:
implications for sequence stratigraphy: Geology, v. 43, no. 4, p. 283-286.
15) Zippi, P. A., 2019, Palynology of samples from measured sections of the Catskill
and Huntley Mountain Formations near Blossburg, PA, from Broussard, D. R.
(personal communication/unpublished data).
16) Kaiser, S. I., Becker, R. T., Steuber, T., and Aboussalam, S. Z., 2011, Climate-
controlled mass extinctions, facies, and sea-level changes around the Devonian–
Carboniferous boundary in the eastern Anti-Atlas (SE Morocco): Palaeogeography,
Palaeoclimatology, Palaeoecology, v. 310, no. 3-4, p. 340-364.

35. Appendix
35

36. Full
Bloss.
Strat.
Column
36

37. Lithofacies
Table
37

38. Facies Subclassifications
and Associated
Lithofacies
38

39. 39
Additional
Sedimentology
Photos
Channel Facies:

40. 40
Additional
Sedimentology
Photos
Proximal
Floodplain
Facies:

41. 41
Additional
Sedimentology
Photos
Distal
Floodplain
Facies:

42. Facies Area Proportion
Blossburg West
Blossburg South
42

43. 43
Facies
Area
Proportion
Raw Data

44. 44
Mapping Channel-
Belt-Scale Scours

45. 45
TLS and GigaPan
Locations

46. 46
3D Outcrop Models - Blossburg South

47. 47
3D Outcrop Models - Blossburg West

48. 48
Grain Size Data across Three Blossburg Outcrops
Bar surface height vs. stratigraphic height
(Blossburg Middle data from Zaklicki, 2020)8

49. 49
Grain Size CDF (cumulative) Plot - D50 Visual

50. 50
Grain Size and Bar Height Data for
Paleoslope Reconstruction Formulae

51. 51
Summary of Data
for Three
Blossburg Outcrops

52. 52
Additional
Devonian-
Mississippian Age
Correlations
European Rhenish Massif stratigraphy and zonation 16

53. 53
Palynology Info
Example of What
Recovered Miospores
Look Like
Recovered miospore examples