Transcript Spatial Analysis of Cinder Cone Distribution at Newberry Volcano, Oregon: Implications for Structural Control on Eruptive Process Steve Taylor and Jeff Templeton Earth and.

Spatial Analysis of Cinder Cone Distribution at
Newberry Volcano, Oregon: Implications for
Structural Control on Eruptive Process
Steve Taylor and Jeff Templeton
Earth and Physical Sciences Department
Western Oregon University
Monmouth, Oregon 97361
• Introduction
• Regional Physiography
• Geologic Setting
• Geomorphic Analysis
• Summary and Conclusion
INTRODUCTION
Cascade Volcanic Arc
Linear chain of volcanoes extending
from southern British Columbia
through Washington and Oregon into
northern California
WOU
Bend
Newberry Volcano
• 56 km east of Cascade Crest
• 40 km south of Bend, Oregon
History of Newberry Work at Western Oregon University
2000-Present
WOU Class Field Trips and Contextual Learning Modules
2000
Friends of the Pleistocene Field Trip to Newberry Volcano
2002-2003
GIS Compilation and Digitization of Newberry Geologic
Map (after MacLeod and others, 1995)
2003
Giles and others, Digital Geologic Map (GSA Fall Meeting)
2003
Taylor and others, Cinder Cone Volume and Morphometric
Analysis I (GSA Fall Meeting)
2005
Taylor and others, Spatial Analysis of Cinder Cone
Distribution II (GSA Fall Meeting)
2007
Taylor and others, Synthesis of Cinder Cone Morphometric
and Spatial Analyses (GSA Cordilleran Section Meeting)
2001-2007
Templeton, Petrology and Volcanology of Pleistocene Ashflow Tuffs (GSA Cordilleran Section Meeting 2004; Oregon
Academy of Science, 2007)
PHYSIOGRAPHIC SETTING
124 W
120 W
122 W
118 W
MJ
Cascades
Cascades
MH
Deschutes-Umatilla
Plateau
Blue Mountains
TFZ
Coast
Western
MW
TS
1
High
Cascadia
44 N
Subduction
Zone
Range
4.5 cm /yr
Willa
mett
e Va
lley
46 N
WRFZ
BFZ
High Lava
Plains
5
6
CL
7
Klamath
Mountains
8
Owyhee
Upland
9
10
Basin and Range
42 N
0
Extent of Newberry Lava Flows
Newberry Caldera
Rhyolite Isochrons (Ma)
Faults:
TFZ = Tumalo Fault Zone
WRFZ = Walker Rim Fault Zone
BFZ = Brother Fault Zone
100 km
9
Newberry Volcano, South View from Lava Butte Lookout
Caldera Summit
Basaltic Aa Lava Flow from
Lava Butte; ~7000 yrs BP
Newberry Volcano, View into Summit Caldera from Paulina Peak
Paulina Lake
East Lake
Geologic Setting
Magma Source in Subduction Zone
Back Arc
Fore Arc
35 – 7 Ma
7 – 0 Ma
Newberry
Position
Eastward Arc
Migration
Decreasing
Slab Dip
122W
120W
Extent of Newberry
lava flows
Rhyolite isochrons (Ma)
0
100
TFZ
km
Newberry Caldera
Fault Zones:
HLP
44N
BFZ=Brothers
TFZ = Tumalo
WRFZ=Walker Rim
BFZ
CR
1
WRFZ
BR
5
6
7
1
6
9 10
8
Geology after Walker and MacLeod
(1991); Isochrons in 1 m.y. increments
(after MacLeod and others, 1976)
Overview of Newberry Volcano
•Shield-shaped composite volcano
•N-S orientation, 64 km x 40 km
•Total Area > 1300 km2
•Summit Caldera Area = 44 km2
•Elevation: 1300 m – 2400 m; Relief ~1100 m
•Composition: Basalt to Rhyolite
•Estimated Volume = 460 km3
•>400 cinder cones and fissure vents
•Quaternary in Age
Normal Polarity <788,000 yrs BP
Tepee Draw Tuff ~500,00 yrs BP
West Flank Tuff ~100,000 yrs BP
Holocene activity: 10,000 – 1200 yrs BP
•One of largest U.S. Quaternary volcanoes
•Historic Annual Precipitation: 30 in/yr
East flank rain shadow of Cascades
Basalt and basaltic andesite flows:
early Pleistocene to Holocene
Basaltic Flows (Pl.- H)
Rhyolite to dacite domes, flows, pumice rings,
and vent complexes: early Pleistocene to
Holocene
Pumice falls, ash flows, and alluvial deposits:
Pleistocene to Holocene
Andesite Tuff (west flank): Pleistocene
Black Lapilli Tuff (west flank): Pleistocene
Alluvial deposits with interbedded lapilli tuff, ash
flow tuff, and pumice fall deposits: Pleistocene
Tepee Draw Tuff (east flank): Pleistocene
Tepee Draw Tuff
Basalt and basaltic andesite of small shields:
Pleistocene
Fluvial and lacustrine sediments: Pleistocene
and Pliocene(?)
Basalt, basaltic andesite, and andesite flows, ash
flow tuffs, and pumice deposits of the Cascade
Range: Pleistocene
Basalt flows and interbedded cinders and scoria
deposits: late Miocene
Rhyolite and andesite flows, domes, and
pyroclastic rocks of Pine Mountain: early
Miocene
Caldera
Newberry Caldera complex
Cinder cones and fissure vents
Cinder Cones
Faults
0
5 km
Study
Area
Oregon
Lava Butte Cone and Aa Flow
~7000 yrs BP (post-Mazama)
Ash &
Pumice
Southeast Cinder Cone Field
GEOMORPHIC ANALYSIS OF
CINDER CONES
Basalt and basaltic andesite flows:
early Pleistocene to Holocene
Cinder Cone Research Questions
Rhyolite to dacite domes, flows, pumice rings,
and vent complexes: early Pleistocene to
Holocene
Pumice falls, ash flows, and alluvial deposits:
Pleistocene to Holocene
Are there morphologic groupings of
~400 cinder cones at Newberry? Can
they be quantitatively documented?
Andesite Tuff (west flank): Pleistocene
Black Lapilli Tuff (west flank): Pleistocene
Alluvial deposits with interbedded lapilli tuff, ash
flow tuff, and pumice fall deposits: Pleistocene
Are morphologic groupings
associated with age and state of
erosional degradation?
Tepee Draw Tuff (east flank): Pleistocene
Basalt and basaltic andesite of small shields:
Pleistocene
Fluvial and lacustrine sediments: Pleistocene
and Pliocene(?)
Are there spatial patterns associated
with the frequency, occurrence, and
volume of cinder cones?
Basalt, basaltic andesite, and andesite flows, ash
flow tuffs, and pumice deposits of the Cascade
Range: Pleistocene
Basalt flows and interbedded cinders and scoria
deposits: late Miocene
Rhyolite and andesite flows, domes, and
pyroclastic rocks of Pine Mountain: early
Miocene
Are there spatial alignment patterns?
Can they be statistically documented?
Newberry Caldera complex
Cinder cones and fissure vents
Faults
Do regional stress fields and fault
mechanics control the emplacement
Study
AreaNewberry volcano?
of 0cinder
cones
at
5 km
Oregon
Methodology


Digital Geologic Map Compilation / GIS of
Newberry Volcano (after McLeod and others, 1995)
GIS analysis of USGS 10-m DEMs

Phase 1 Single Cones/Vents (n = 182)
 Phase 2 Composite Cones/Vents (n = 165)

Morphometric analyses

Cone Relief, Slope, Height/Width Ratio
 Morphometric Classification

Volumetric Analyses

Cone Volume Modeling
 Volume Distribution Analysis

Cone Alignment Analysis

Two-point Line Azimuth Distribution
 Comparative Monte Carlo Modeling (Random vs. Actual)
Single Cone DEM Example
COMPOSITE
(n = 182)
(n = 165)
Composite Cone
DEM Example
RESULTS OF MORPHOMETRIC
ANALYSES – SINGLE CONES
Table 1. Explanation of Qualitative Cone Morphology Rating
Single Cones (n=182)
1
2
3
4
5
6
7
Good-Excellent
Good
Moderate-Good
Moderate
Moderate-Poor
Poor
Very Poor
Cone shape with vent morphology
Cone shape with less defined vent morphology
Cone shape, lacks well-defined vent morphology
Cone shape, no vent
Cone shape, poor definition
Lacks cone shape
Lacks cone shape, very poorly defined morphology
Lava Butte
(Cone Morphology Rating = 1)
0
Lava Butte
(Cone Morphology Rating = 1)
500 m
Lava Butte
(Cone Morphology Rating = 1)
0
Pumice Butte
(Cone Morphology Rating = 4)
Hunter Butte
(Cone Morphology Rating = 7)
500 m
Hunter Butte
(Cone Morphology Rating = 7)
Pumice Butte
(Cone Morphology Rating = 4)
Lava Butte
(Cone Morphology Rating = 1)
Lava Butte
(Cone Morphology Rating = 1)
0
0
500 m
Hunter Butte
(Cone Morphology Rating = 7)
500 m
n=182
Single Cones
Table 2. Summary of Relevant Cone Morphometry Data.
Cone
Morphology
Class
Class 1
Class 2
Class 3
Class 4
Class 5
Class 6
Class 7
All Cones
No.
Avg Slope (deg) Cone Height (m)
11
21
10
35
35
11
59
Mean Variance
19.9
11.8
18.2
10.5
18.1
2.7
14.9
12.1
14.4
10.6
11.9
13.7
10.2
19.0
182
13.6
24.2
Hco/Wco
Mean Variance Mean Variance
132.4 1344.9
0.18
0.0012
124.4 2282.4
0.20
0.0073
126.2 1991.0
0.19
0.0017
76.2
1918.4
0.15
0.0014
78.1
1682.9
0.15
0.0012
59.5
1721.3
0.13
0.0025
50.4
1401.3
0.14
0.0046
76.4
2520.7
0.2
0.0038
30
Morphometric Group II
n = 11
n = 21
Average Cone Slope (Degrees)
25
n = 35
n = 11
n = 10
n = 59
20
n = 35
15
10
Morphometric Group I
5
Mean
Range
Standard Deviation
0
1
Single Cones
2
3
4
Cone Morphology Rating
5
6
7
250
n = 10
Morphometric Group II
n = 35
200
n = 11
n = 21
n = 35
n = 59
Cone Height (meters)
n = 11
150
100
50
Morphometric Group I
0
1
Single Cones
2
3
4
Cone Morphology Rating
5
6
7
0.6
Morphometric Group II
0.5
Cone Height / Cone Width
n = 21
0.4
n = 59
0.3
n = 10
n = 11
n = 35
n = 35
0.2
n = 11
0.1
Morphometric Group I
0
1
Single Cones
2
3
4
Cone Morphology Rating
5
6
7
Single Cones
Table 3. Results of Systematic T-Test Analyses.
Cone
Morphology
Class
df

Class 1-Class 2
30
0.05
1.38
0.089
1.70
0.177
2.04
Accept Ho
Group I
Class 2-Class 3
29
0.05
0.11
0.458
1.70
0.915
2.05
Accept Ho
Group I
Class 3-Class 4
43
0.05
2.85
0.003
1.68
0.007
2.02
Reject Ho
Group II
Class 4-Class 5
44
0.05
0.36
0.360
1.68
0.719
2.02
Accept Ho
Group II
Class 5-Class 6
44
0.05
2.05
0.023
1.68
0.046
2.02
Group II
Class 6-Class 7
92
0.05
1.88
0.032
1.66
0.064
1.99
Accept Ho
Accept Ho
Class 1-Class 2
30
0.05
0.49
0.315
1.70
0.631
2.04
Accept Ho
Group I
Class 2-Class 3
29
0.05
-0.10
0.459
1.70
0.918
2.05
Accept Ho
Group I
Class 3-Class 4
43
0.05
3.17
0.001
1.68
0.003
2.02
Reject Ho
Group II
Class 4-Class 5
44
0.05
-0.13
0.450
1.68
0.899
2.02
Accept Ho
Group II
Class 5-Class 6
44
0.05
1.30
0.100
1.68
0.200
2.02
Group II
Class 6-Class 7
92
0.05
1.09
0.140
1.66
0.280
1.99
Accept Ho
Accept Ho
Class 1-Class 2
30
0.05
-0.61
0.272
1.70
0.545
2.04
Accept Ho
Group I
Class 2-Class 3
29
0.05
0.40
0.346
1.70
0.692
2.05
Accept Ho
Group I
Hco/Wco Class 3-Class 4
43
0.05
2.92
0.003
1.68
0.006
2.02
Reject Ho
Group II
Class 4-Class 5
44
0.05
0.20
0.420
1.68
0.840
2.02
Accept Ho
Group II
Class 5-Class 6
44
0.05
0.93
0.179
1.68
0.359
2.02
Group II
Class 6-Class 7
92
0.05
-0.39
0.349
1.66
0.697
1.99
Accept Ho
Accept Ho
Savg
Hco
t
t
P(T<=t)
P(T<=t)
Morphometric
t Stat
Critical
Critical Test Result
one-tail
two-tail
Group
one-tail
two-tail
Group II
Group II
Group II
Moprhometric Group I
(Morphology Rating
Classes 1, 2, and 3)
“Youthful”
Morphometric Group II
(Morphology Rating
Classes 4, 5, 6, and 7)
“Mature”
Northern Domain
Group I: n = 26 (14%)
Group II: n = 76 (42%)
Newberry
Caldera
0
5 km
Southern Domain
Group I: n = 16 (9%)
Group II: n = 64 (35%)
Single Cones
VOLUMETRIC ANALYSES:
SINGLE + COMPOSITE CONES
VOLUME METHODOLOGY
Original DEM of
A. Original 10-m DEM of
Lava
Lava
ButteButte
Cone
Clip cone footprint from 10-m
USGS DEM (Rectangle 2x Cone
Dimension)
Zero-mask cone elevations,
based on mapped extent from
MacLeod and others (1995)
Re-interpolate “beheaded” cone
elevations using kriging
algorithm
Cone Volume =
(Cone Surface – Mask Surface)
B. Masked 10-m
DEM of
of
Masked
DEM
Lava Butte Cone
Lava Butte
0
500 m
CONE VOLUME SUMMARY
(SINGLE AND COMPOSITE)
Cubic Meters
CONE ALIGNMENT ANALYSES
SINGLE + COMPOSITE
Cone lineaments anyone? Question: How many lines can be created
by connecting the dots between 296 select cone center points?
Answer:
Total Lines = [n(n-1)]/2 =
[296*295]/2 = 43,660
possible line combinations
Follow-up Question: Which cone
lineaments are due to random chance
and which are statistically and
geologically significant?
Frequency
METHODS OF CONE
LINEAMENT ANALYSIS
Azimuth
GIS
Frequency
“POINT-DENSITY
METHOD”
(Zhang and
Lutz, 1989)
“TWO-POINT
METHOD”
(Lutz, 1986)
Azimuth
30
0W
REGIONAL FAULTTREND ANALYSIS
Tumalo Fault Zone
n = 142
20
122W
10
0
100
0
TFZ
km
-90
-60
-30
0
BFZ
R
Frequency
30
60
90
Walker Rim Fault Zone
n = 92
20
HLP10
0
-90
1
WRFZ
30
30
-60
-30
0
30
60
90
Brothers Fault Zone
n = 165
20
5
10
BR
6
0
-90
7
8
-60
-30
0
Azimuth
30
60
90
CONE TWO-POINT ALIGNMENT
ANALYSIS (after Lutz, 1986)
2000
95%
95%Critical
Critical Value
Value
NULL HYPOTHESIS
Distribution of Actual Cone Alignments =
Random Cone Alignments
1000
C.
0
-90
EXPECTED ALIGNMENT FREQUENCY:
FEXP = (n*(n-1) / (2*k))
NORMALIZED ALIGNMENT FREQUENCY:
FNORM = (FEXP / FAVG) * FOBS
FNORM = normalized bin frequency
FEXP = expected bin frequency
FAVG = average random bin frequency
FOBS = observed bin frequency
3000
Frequency
n = No. of Cinder Cones
k = No. of Azimuthal Bins
Normalized Newberry Two-Point Azimuths
Normalized
Cone Azimuths
(Combined
NorthTwo-Point
and South Domains)
B.
-60
-30
0
30
60
90
Two-Point Azimuths: Random Simulation
(Combined North and South Domains)
Random Two-Point Cone Azimuths
n =n296
= cones
296 / /Replicate
replicate
Replicate no. = 300
Replicates
= 300
Line Segments / Replicate
= 43,660
2000
1000
0
-90
3000
-60
-30
0
30
60
90
Two-Point Azimuths: Newberry Cones
ActualNorth
Two-Point
Azimuths
(Combined
and SouthCone
Domains)
=296
296 cones
n =nTotal
Line Segments = 43,660
Line Segments = 43,660
CRITICAL VALUE:
2000
LI = [(FEXP / FAVG) * FAVG] + (tCRIT * RSTD)
1000
FEXP = expected bin frequency
FAVG = average random bin frequency
RSTD = stdev of random bin frequency
tCRIT = t distribution ( = 0.05)
A.
0
-90
-60
-30
0
Azimuth
30
60
90
TWO-POINT ANALYSIS RESULTS
NORTH DOMAIN
SOUTH DOMAIN
Normalized Newberry Two-Point Azimuths
(North Domain)
500
Normalized Newberry Two-Point Azimuths
(South Domain)
600
95%
Critical
95%
Critical
ValueValue
400
95% Critical Value
95% Critical Value
200
0
-90
-60
-30
0
30
60
90
Two-Point Azimuths: Random Simulation
(North Domain)
n = 149 cones / Replicate
500
Frequency
0
B.
0
-90
-60
-30
0
30
60
90
60
90
60
90
Two-Point Azimuths: Random Simulation
(South Domain)
600
n = 149 / replicate
Replicate no. = 300
Line
Segments / Replicate
= 11,026
Replicates
= 300
Frequency
C.
C.
cones
/ Replicate
nn== 147
147
/ replicate
Replicate no. = 300
Replicates
300 = 10,731
Line Segments / =
Replicate
400
200
0
-90
-60
-30
0
30
60
90
Two-Point Azimuths: Newberry Cones
(North Domain)
500
-90
B.
-30
0
30
Two-Point Azimuths: Newberry Cones
(South Domain)
600
n = 149
cones
n = 149
cones
Total
Line
Segments== 11,026
11,026
Line Segments
-60
n = 147
cones
n = 147 cones
Total Line Segments
= 10,731
Line Segments
= 10,731
400
200
0
A.
-90
-60
-30
0
Azimuth
30
60
90
A.
0
-90
-60
-30
0
Azimuth
30
POINT-DENSITY METHOD
(Zhang and Lutz, 1989)
1-km wide filter strips with 50% overlap
Filter strip-sets rotated at 5-degree azimuth increments
Tally total number of cones / strip / azimuth bin
Calculate cone density per unit area
Compare actual densities to random (replicates = 50)
Normalize Cone Densities: D = (d – M) / S
D = normalized cone density
d = actual cone density (no. / sq. km)
M = average density of random points (n = 50 reps)
S = random standard deviation
Significant cone lineaments = >2-3 STDEV above random
Comparison of Fault Trends and
Cinder Cone Lineaments at
Newberry Volcano
Tumalo
Fault
Zone
Cind er cone location
10
Cone lineament determined by
M onte Carlo point-density method
o f Zh ang and Lutz (1989)
20
n = 142
Brothers
Fault
Zone
TFZ
BFZ
n = 87
10
5
20
n = 165
Missing
WRFZ?
Cinder Cone Lineaments
(Critical L-value >2 SD)
Walker Rim
Fault
Zone
10
20
n = 92
0
10 km
SUMMARY AND CONCLUSION
I. CONE MORPHOLOGY
•




•
Degradation Models Through Time (Dohrenwend and others, 1986)
Diffusive mass wasting processes
Mass transfer: primary cone slope to debris apron
Reduction of cone height and slope
Loss of crater definition
Newberry Results (Taylor and others, 2003)




Group I Cones: Avg. Slope = 19-20o; Avg. Relief = 125 m; Avg. Hc/Wc = 0.19
Group II Cones: Avg. Slope = 11-15o; Avg. Relief = 65 m; Avg. Hc/Wc = 0.14
Group I = “Youthful”; more abundant in northern domain
Group II = “Mature”; common in northern and southern domains

Possible controlling factors include: degradation processes, age
differences, climate, post-eruption cone burial, lava composition, and
episodic (polygenetic) eruption cycles
II. CONE VOLUME RESULTS
•
Newberry cone-volume maxima align NW-SE with the Tumalo fault zone;
implies structure has an important control on eruptive process
III. CONE ALIGNMENT PATTERNS
•
•
•
•
•
Newberry cones align with Brothers and Tumalo fault zones
Poor alignment correlation with Walker Rim fault zone
Other significant cone alignment azimuths: 10-35o, 80o, and 280-295o
Results suggest additional control by unmapped structural conditions
Cone-alignment and volume-distribution studies suggest that the
Tumalo Fault Zone is a dominant structural control on magma
emplacement at Newberry Volcano
IV. CONCLUDING STATEMENTS
•
•
This study provides a preliminary framework to guide future
geomorphic and geochemical analyses of Newberry cinder cones
This study provides a preliminary framework from which to pose
additional questions regarding the complex interaction between stress
regime, volcanism, and faulting in central Oregon
Future Work
Coordination of cone morphology studies with USGS basalt flow
mapping, stratigraphic, and geochemical research (Donelly-Nolan)
Use of cone morphology classes to guide geochemical sampling and
radiometric dating studies
Use of cone morphology classes to guide soil chronosequence work
Use of cone alignment patterns
to further investigate the
relationship between fault
mechanics, stress regime, and
magma emplacement
mechanisms
ACKNOWLEDGMENTS
Funding Sources:
Western Oregon University Faculty Development Fund
US Geological Survey Small Grants Program
WOU Student Research Assistants:
Jeff Budnick, Chandra Drury, Jamie Fisher, Tony Faletti
Denise Giles, Diane Hale, Diane Horvath, Katie Noll, Rachel
Pirot, Summer Runyan, Ryan Adams