Geology 399 Finial Project Jonathan W.F. Remo

Statistical Analysis of the Lithologic and Structural Controls on Mass Movement in

the New River Gorge, West Virginia

Introduction

In the summer of 1998, a study was undertaken to investigate the geologic controls of landslidesand landslide deposits within the New River Gorge (NRG). Three study areas of the NRG were selected based on differences in geology in order to compare and contrast the effects of different bedrock and structural geology on the landslides. The upper gorge study area extends from Hinton to Sandstone Falls, West Virginia. The middle gorge study area extends from Glade Creek to the Plateau. The lower gorge study area extends from Keeneys Creek to Fayette Station.

Mapping in the three study areas at a scale of 1:24,000 has revealed 125 prehistoric, 51 historic landslide deposits. At least 41 of the historic landslide deposits incorporate mine-spoil. Thelithology of bedrock is the most important determinant to the type, size, and composition of the landslides. Joints indirectly influence the orientation of the landslides and the dip of strata effects the type of motion.

The prehistoric events have been analyzed to determine long-term relationships between lithology, structure and landslides because historic landslides are more related to human activities than a result of natural phenomena. The upper gorge study area has only 12 mappable prehistoric and historic landslide deposits, the least of the three areas. The bedrock is dominated by weak shale, which weathers rapidly into fine-grained materials. The rapid weathering of the fine-grained landslide deposits makes it difficult to recognize landslide landforms. The fine-grained materials produced by the weathering of shale bedrock are easily removed from the landscape by stream flow.

The middle gorge area has 65 prehistoric and 3 historic mappable landslide deposits The upper gorge study area has only 12 mappable prehistoric and historic landslide deposits, the least of the three areas. The bedrock is dominated by weak shale, which weathers rapidly into fine-grained materials. The rapid weathering of the fine-grained landslide deposits makes it difficult to recognize landslide landforms. The fine-grained materials produced by the weathering of shale bedrock are easily removed from the landscape by stream flow. The middle gorge area has 65 prehistoric and 3 historic mappable landslide deposits. The middle gorge area is characterized by shale-dominated valley

Introduction Continued

sidewalls with a quartz sandstone capped rim. The sandstone is extremely resistant and produces boulders 2 to 4 meters in long axis. The boulders make landslides landforms difficult to erode. Therefore, the landforms are better preserved making, them more recognizable.

The lower gorge representative area has 49 prehistoric and 5 historic mappable landslides mappable deposits. The lower gorge area is characterized by quartz-sandstone-dominated valley sidewalls. The Nuttall quartz sandstone member at the top of the lower gorge study area is 20 to 40 meters thick. This unit produces extremely large blocks up to 40 meters in long axis. This blocky material is extremely difficult to erode. These landslide deposits are significant enough to alter the flow of the New River and cause large rapids in the lower gorge. e middle gorge area is characterized by shale-dominated valley sidewalls with a quartz sandstone capped rim. The sandstone is extremely resistant and produces boulders 2 to 4 meters in long axis. The boulders make landslides landforms difficult to erode. Therefore, the landforms are better preserved making, them more recognizable.

The lower gorge representative area has 49 prehistoric and 5 historic mappable landslides mappable deposits. The lower gorge area is characterized by quartz-sandstone-dominated valley sidewalls. The Nuttall quartz sandstone member at the top of the lower gorge study area is 20 to 40 meters thick. This unit produces extremely large blocks up to 40 meters in long axis. This blocky material is extremely difficult to erode. These landslide deposits are significant enough to alter the flow of the New River and cause large rapids in the lower gorge.

Study Areas

Comments• There seems to be little if any correlation between joint trends and orientation of mass movement• There is a strong correlation between the Slopes of Lower and Middle Gorge• There is a strong relationship between the Middle and Upper Gorge Study Areas• There maybe a correlation between the joint sets in the Upper and Middle Gorge Study area.• A relationship may exist between the orientation of the mass-movement deposits in the Upper and Middle Gorge.

Correlation Matrix

U Failure U Area of Upper Gorge U s M Failure M Area of Middle Gorge M L Gorge L Area of Lower Gorge Lower Gorge

Orintation Failure m2 Slope Joints Orientation Failure m2 Slope Joints Orientation Failure m2 Slope JointsU Failure Orientation 1.00

U Area of Failure m2 -0.23 1.00Slope of Upper Gorge 0.07 0.06 1.00U Joints -0.24 0.25 0.20 1.00M Failure Orientation -0.23 -0.22 -0.29 -0.20 1.00

M Area of Failure m2 0.12 0.17 0.23 -0.18 -0.23 1.00M iddle Gorge Slope 0.09 0.03 0.74 0.25 0.09 0.03 1.00M Joints -0.01 -0.13 0.03 0.39 -0.24 0.25 0.25 1.00L Failure Orientation -0.23 -0.16 -0.38 -0.35 -0.12 -0.17 -0.54 -0.35 1.00

L Area of Failure m2 0.05 0.02 -0.11 -0.03 0.05 -0.17 -0.08 -0.03 0.15 1.00Slope of Lower Gorge 0.03 0.02 0.42 0.26 0.03 0.01 0.92 0.26 -0.47 -0.08 1.00L Joints -0.20 0.16 -0.58 0.17 -0.20 0.05 -0.14 0.17 -0.05 -0.06 0.10 1.00

Orientation of Joints vs. Orientation of Mass Movement Deposits in Middle Gorge Study Area

0306090

120150180210240270300330360

0 30 60 90 120 150 180 210 240 270 300 330 360

Orientation Joint

Ori

en

tati

on

of

Mas

s M

ove

me

nt

De

po

sit

s

Orientation of Joint Orientation vs. Mass Movement Deposits in Lower Gorge Study Area

0306090

120150180210240270300330360

0 30 60 90 120 150 180 210 240 270 300 330 360

Orientation of Joints

Ori

en

tati

on

of

Mas

s M

ove

me

nt

De

po

sit

s

Orientation of Joints vs. Orientation of Mass Movement Deposits in Upper Gorge Study Area

0306090

120150180210240270300330360

0 30 60 90 120 150 180 210 240 270 300 330 360

Orientation of Joints

Ori

en

tati

on

of

Mas

s M

ove

me

nt

De

po

sit

s

• There appears to be is little if any relationship depicted. Calculated R values are as follows: Upper Gorge Study Area 0.271 Middle Gorge Study Area 0.110 Lower Gorge Study Area 0.017

• Pearson product moment coefficient are used to determine if there is linear relationship between the orientation of joints and the orientation of mass movement deposits.

Analysis of Joints

Precentage of Aspect Frequenecy vs. Precentage of Total Area of Massmovment Deposits in The Upper Gorge Study

Area

0.00

5.00

10.00

15.00

20.00

25.00

30.00

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00

Precentage of Aspect Frequency

Pre

cen

tag

e o

f T

ota

l Are

a o

f M

ass

mo

vem

en

t D

ep

os

its

Precentage of Aspect Frequenecy vs. Precentage of Total Area of Massmovment Deposits in The Low er Gorge Study Area

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00

Percent of Total Aspect Frequency

Perc

ent o

f To

tal A

rea

of M

assm

ovem

ent

Dep

osits

Precentage of Aspect Frequenecy vs. Precentage of Total Area of Massmovment Deposits in The Middle

Gorge Study Area

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

0.00 5.00 10.00 15.00 20.00 25.00 30.00

Percentage Total Aspect Frequency

Pe

rce

nta

ge

of

To

tal A

rea

of

Mas

sm

ove

me

nt

De

po

sit

s

• Pearson product moment coefficient is used to determine linear relationships between aspect and the orientation of mass-movement deposits.• There is a correlation between aspect and the orientation of mass movement deposits. The Middle and Lower Gorge Study Areas have the highest R values, 0.891 and 0.710 respectively. The Upper Gorge has a lower correlation with an R values of 0.465. This is due to the lack of mass-movement deposits in the Upper Gorge Study Area.

Mass Movement Deposits andTheir Relation to Aspect.

Comparison of SlopesPrecentage of Slope Frequency for the Lower Gorge vs. the

Middle Gorge

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00

Precentage of Frequency of the Lower Gorge

Pre

cen

tag

e o

f Fr

eq

ue

ncy

fo

r th

e

Mid

dle

Go

rge

Precentage of Frequency of Slope in the Lower Gorge vs. Upper Gorge Study Area

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00

Precentage of Frquency for The Lower Gorge

Pre

cen

tag

e o

f Fr

eq

ue

ncy

fo

r th

e

Up

pe

r G

org

e S

tud

y A

rea

Percentage of Slope Frequency Middle Gorge Study Area vs. Upper Gorge Study Area

0

500

1000

1500

2000

2500

3000

3500

4000

0 500 1000 1500 2000

Percentage of Slope of the Middle Gorge Study Area

Pe

rce

nta

ge

of

Slo

pe

of

the

Up

pe

r G

org

e S

tud

y A

rea

• The Lower and Middle Gorge Study Areas have similarly steep slopes. While the Upper and Lower and Middle and Upper Gorge Study Areas have less similar slopes.

Pearson's Correlation Coefficients are as follows:

Lower vs.... Middle Gorge 0.925Middle vs... Upper Gorge 0.747Lower vs... Upper Gorge 0.490

Precentage of Lithologies in the Lower Gorge Study Area

Sandstone48%

Coal1%

Shale19%

Shale w / interbedded S.S.

7%

Concealed Section

25%

Precetn of Lithologies in the Middle Gorge Study Area

Sandstone42%

Coal1%

Shale19%

Shale interbedded w / S.S.

11%

S.S. interbedded w / Shale

11%

Concealed Section16%

Precentage of Lithologies in the Upper Gorge Study Area

Sandstone18%

Shale46%

Shale w / interbedded S.S.

23%

Limey Sandstone

4%

Limestone6%

S.S. w / interbedded

Shale 3%

Lithologies of the Study Areas

• The reason for the difference in slope stems from the bedrock geology. The Middle and Lower gorge study areas have more resistant lithologies than the Upper gorge. This is apparent in these pie graphs. The lower and middle gorge have more sandstone in the valley-side walls than upper gorge. Hence the steeper and more similar slopes.

Lithology of Lower vs. Middle Gorge Study Area

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

0.00 10.00 20.00 30.00 40.00 50.00

Precentages of Lithology in Lower Gorge

Pre

cen

tag

e o

f L

ith

olo

gie

s in

Mid

dle

G

org

e

Lithology of Lower Gorge vs. Lithology of Upper Gorge

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

0.00 10.00 20.00 30.00 40.00 50.00

Percentage of Lithology in the Lower Gorge

Pre

cen

tag

e o

f L

ith

olo

gy

in t

he

Up

pe

r G

org

e

Litholgoy of Lower Gorge vs Upper Gorge

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

0.00 10.00 20.00 30.00 40.00 50.00

Precentage of Lithologies Lower Gorge

Pre

cen

tag

e o

f L

ith

olo

gie

s in

Up

pe

r G

org

e

• Pearson product moment coefficient are used to further determine if there is relationship between the lithologies of the study areas.

• The Middle Gorge and Lower Gorge Study Areas shows a strong correlation in lithology with a R value of 0.949. While comparison of the Upper with Lower and Middle Gorge Study Areas shows a much weaker correlation.

Correlation of Lithologies

Conclusions

• Mass-movement deposits show a strong correlation with aspect. (I.e. debris slides go down hill)

• The Middle and Lower Gorge have similar slopes and more similar lithologies than Upper Gorge. This is due to differences in lithology. These differences in lithology effect the preservation and size of mass-movement deposits.

• Joints trends show no statistical correlation to orientation of mass-movement deposits.