NU REG /CR-0874

RECENT VERTICAL MOVEMENT OF THE LAND SURFACE IN THE LAKE COUNTY UPLIFT AND BASIN AREAS, , MISSOURI AND KENTUCKY

R. G. Stearr.s

Vanderbilt University

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: L:i- 3. 0 001 Prepared for U. S. Nuclear Regulatory Commission

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This report was prepared as an account of work sponsored by an agency of the Government. fleither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or resprnsibility for any third party's I use, or the results of such use, of any information, apparatus product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned righ ts.

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Available from National Technical Information Service Springfield, Virginia 22161 NU REG /CR-0874 R6,R A

RECENT VERTICAL MOVEMENT OF THE LAND SURFACE IN THE LAKE COUNTY UPLIFT AND REELFOOT LAKE BASIN AREAS, TENNESSEE, MISSOURI AND KENTUCKY

Prepared by R. G. Stearns

Vanderbilt University Department of Geology Nashville, TN 37235

Manuscript Completed: Merch 1979 Date Published: June 1979

Prepared for Division of Reactor Safety Research Office of Nuclear Regulatory Research U. S. Nuclear Regulatory Commission Washington, D.C. 20555 NRC FIN No. B5960 3 } fj ij 0 2 i

CONTENTS

Abstract iv

Introduction 1

Previous Studies 4 Background 4 Definitions and Descriptions of Tiptonville Dome, Reelfoot Lake Basin, and other Features 5 The Present Writer 's Use of Tiptonville Dome, Reelfoot Lake Rasin, and Lake County Uplift 9

Present Study 13

Acknowledgmente 14

Flood Maps 15 Uplift of Tiptonville Dome, Ridgely Ridge, and Bessie Ridge as Judged from Soil Maps and Topography 17

Topographic Envelopes 21 General 21 Detailed Topographic Envelope 22 Generalized Topographic Envelope 22

Modern Erosion of the Topographic Highs 26

Relation to Deeper Structure 29 Evidence from Gravity Anomaly Data 29 Evidence from Earthquake Epicenters 29

Conclusions 33

References Cited 37

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ILLUSTRATIONS

No. Page

1- Map showing location of the study area within the Mississippi

Embayment ...... 2

2- The study area showing the area of uplift and area of " Maxi-

mum" uplift (stippled) as mapped by Fuller ...... 3

3- Outline map showing the topographic features considered in

this report that have or may have a tectonic origin ..... 11

4- Tiptonville Dome as part of a series of topographic highs,

' which are drawn as islands during a flood that of 1937 . 36

5- Soil map showing areas underlain by older soils ..... 18

6- Elevation of the areas shown on Figure 5 to be underlain by

older soile ...... 19

7- Detailed configuration of the alluvial plain of the

Mississippi River in the study area ...... 23

8- Generalized configuration of the entire width of the

Eastern Lowlands of the alluvial plain c f the Mississippi

River ...... 24

9- Area occupied by channels of the since 1765, and the areas where lateral erosion has likely destroyed

part of the Tiptonville Dome and Lewis Prairie ...... 27

p (\bb 3 _, u iii

No. Page

10- The flood islands as they may have been in 1812 ...... 28 11- Bouguer gravity anomaly map of the Tiptonville Dome, Ridgely

Ridge and Reelfoot Lake area ...... 30 12- Earthquake epicenters in Lake County, Tennessee, and

vicinity ...... 31

Tables

1- Soils in the study area that are described as having a

"B" horizon ...... 20 2- Table of vertical movement, estimates and bases, for the

various topographic features ...... 34

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ABSTRACT

Tiptonville Dome, an established tectonic uplift, is one in a 20 mile series of en echelon topographic highs , most or all of which are uplifts. These features are too high to have been flooded dur- ing the largest historic floods. During these floods they were temporary islands. From Lewis Prairie, at New Madrid in Missouri, five such topographical 3y high areas extend southward across the

Mississippi River to Ridgely, Tennessee. Although separated now due to modern river erosion, they were nearly continuous in 1811.

Contour trends reveal a squarish topographic bulge west of the

" flood islands," the western corner of which is near Portageville,

Misscuri. It may have been uplifted with, but less than, the

" flood islands." This bulge and the topographic highs comprise the Lake County Uplift.

Vertical movement is interpreted from variations in eleva- tion of the alluvial plain surface and old soils. Individual features, datums, and vertical movement estimated are as follows:

TOPOGRAPHIC DATUM OF A DATUM OF ___ FEATURE LARGE FLOOD REELFOOT LAKE Ridgely Ridge Up 5-15 feet Up 20-25 feet Tiptonville Dome Up 10-20 feet Up 35-40 feet Bessie & Washpan Ridges Up 0-10 feet Up 15-20 feet Lewis Prairie Up 5 feet Up 5 feet Reelfoot Lake Basin ------Portageville Bulge ----- Up 0- 5 feet Ridgely Ridge and Tiptonville Dome in Tennessee correlate with positive gravity anomalies, and small earthquakes are concentrated beneath or near them. Thus these topographic features may be sur- face manifestations of deep-scated tectonic movements that contpgue Ob' }'70'" today. 1

INTRODUCTION

Stratigraphically defined structural datum planes, from which historic and late pre-historic vertical movements of tectonic origin can be measured, are obscure or very irregular in the New Madrid earthquake region of southeast Missouri and northwest Tennessee.

Unconformities such as that at the base of the high level continental deposits of Pleistocene and Pliocene (?) age and the base of the Mississippi River alluvium of Late Pleistocene and Recent age are irregular and hundreds of thousands or more years old. These provide poor data from which to recognize recent structural dis- placements. Possibly a more senitive datum is the -elatively even

Holocene surface of the Mississippi River alluvial plain. A coincidence between the shape of this surface, and several other mapped parameters including distribution of soils with a B-horizon. Bouguer gravity anomaly, and distribution of earthquakes will be shown.

F.gure 1 shows the general location of the area referred to in t-his report. Figure 2 shows the same area as n apped by Fuller

(1912, Plate 1).

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e MEMPHIS / TENN __ __ ------{ ARK -'f(f 35* MISS LA O 50 MILES

Figure 1- Map showing location of the study area within the Mississippi Embayment. The Tiptonville Dome limits of Fuller are shown by the dotted line around Tiptonville, Tennessee.

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NEW MADRID

N KY HICK- 1 i MAN MO / ' KY KY __ (/ 2- ~~ ~/ ~ TENN

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Figure 2- The study area showing the area of uplift and the area of " maximum" uplift (stippled) as mapped by Fuller (1912, redrawn from a pa rt of his Plate 1). Compare this with

Figure 3. , j,jO C b, 4

PREVIOUS STUDIES ,

Background

4 Vertical movements have been inferred for portions of the

region in the vicin.ty of Lake County, Tennessee, by Usher (1837),

McGee (1892), Fuller (1912), and Fisk (1944). Fuller mapped the

limits of uplift and an area of greater uplift of the Tiptonville

Dome, which he named (Figure 3). Glenn (1933) suggested that the Reel-

foot Lake sunken lands were the result of compaction during the

earthquakes of 1811-12, rather than downfaulting, but Fisk (1944)

asserted that a fault separates the Tiptonville ome and Reelfoot

Lake sunken land, and he supported this interpretation by drill

records as well as river elevation data. Krinitzsky (1950), dis-

cussed criteria for recognizing faults; one of his criteria was

irregularities that appear on profiles of the land surface.

Later Saucier (1970' suggested a physiographic origin for the

St. Francis e' Ink land. Past work leaves open the possibility of

much vertical tectonic movement, but alternative explanations

are offered. This present paper, though not concerned with

faulting versus " bulging" uses lateral changes in the land

surface elevation and gradients on maps to infer likely tectonic uplift and downsinking patterns.

pI ' n_ v ,f) J V 5

Definition and Descriptions of Tiptonville Dome, Reelfoot Lake Basin, and Other Features

The Tiptonville Dome and Reelfoot Lake Basin were first described in the geological literature ay Usher (1837) who had seen them several years before writing his report and had repro- duced them from memory. He noted that the entire left (Tennessee) bank of the river was uplifted from New Madrid south to the mouth

of the , or from about latitude 36 35' to latitude 36 .

The uplift was said to be "only a few feet," but yet it obstructed the mouth of Reelfoot Creek and the Obion River. He also stated

that "this obstruction formed several lakes along back of this . . .

It is quite probable that the land there was depressed in some degree in order to form these lakes." Usher was explic_e that the uplift is on the Tennessee side and said that on the Missouri side New

Madrid sank. Lyell (1849) visited New Madrid in 1846 and described the occurrence of the 1811 ground movement (p. 174) as foll ows:

". . . the ground swelled up so the river flowed backward for a time, carrying several flatboats northward against the stream."

Lyell presented a landslide explanation for sinking of the Missouri side at New Madrid which was, at the time of his visit, sliding into the river. The present Lty is on the riverbank yet nearly a mile north of its 1811 location. Lyell also presented evidence that the

Missouri side had risen. Portage Bayou which used to make a con- nection by boat to a point on the Mississippi just south of

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New Madrid nas been dry since the earthquake.

McGee (1892) described the uplift (which he called the Lake

County uplift, a name this writer will adopt) and the Reelfoot lake

Basin. He said (p. 411) that the uplift includes "all of Lake

County, Tennessee, and a considerable area in Missouri, on the opposite side of the river. This area, some 20 miles in mean diameter, bulges upward in a low dome, 20 or 25 feet above the level of the alluvial plain. " McGee explicitly stated that the uplift occurs on both sides of the Mississippi River, but presents no facts in support for uplift of the Missouri side, though Lyell did. McGee agreed with the view that the river ran backward

(as eyewitnesses claimed, but were generally not believed) to fill Reelfoot Lake Basin as a result of the bulge damming up the low-gradient river. Because of the lack of sediment deltas where streams entered the lake in 1892, McGee reasoned that Reelfoot

Lake Basin was filled suddenly with water. He emphasized the fact that, during floeds on the Mississippi River, Reelfoot Lake level rose about 20 fee t , so that the " Lake County uplif t is transformed into a double island" (p. 412).

Fuller (1912, p. 63) first called this uplift the Tiptonville

Dome and censidered the feature to include areas on both sides of the Mississippi River (Figure 2). He used the description more or less as presented by Usher and McGee as summarized above. The dimensions of the Tiptonville Dome were given by Fuller (p. 6 2. )

330 CI3 7

as 15 miles long and 5 to 8 miles wide. The maximum uplift

" was recognized by him as being . . . in a relatively narrow

belt extending from near the south side of the Mississippi at

New Madrid a little east of south to a point 2 or 3 miles south

of Reelfoot Lake. The uplift of this belt has been sufficient to

raise the surface above the highest floods . . . The amount of

uplift, ju6ging from the fact that the land is only 10 to 15

feet above the high water mark, could not have been over 15 to

20 feet." Fuller also recognized that not all the uplift was

necessarily due to the 1811 earthquake. As he points out:

". . . but if Little Prairie (Lewis Prairie on his map, a name

this writer will use), on which New IIadrid is situated, is a

part of the dome, Lae uplift will have to be referred to an

earlier date, as New Madrid Village previous to the shock was on

high land, never covered by the floods. He mapped the dome as

an egg-shaped feature. On his map (Plate 1) Fuller excludes

New Madrid and the high ground about 4 miles to the south and

west (Fig. 2).

Fuller also gave an estimate of the depression of the

original land surface below the normal water level in Reelf,>ot

Lake as- "2 to 10 feet, and possibly even more locally . . ."

(p. 68). This present paper in large measure is a refinement of Fuller's work, extending the limits of, giving a more I . E. ') ;U" n o ' ' 8

detailed shape to, and variation in the area of uplift.

Fuller is the only autnor to state a preference for the mode of origin of aplifts and sunken areas. He thought they most

lixu2 7 ucie superficial wrinkles of the Cretaceous and younger

Mississippi Embayment fill as it moved laterally toward the

Mississippi River and Gulf of Mexico during earthquakes, a con- clusion not supported by the present study.

Glenn (1933) appears to use Fuller's smaller area of maximum uplift which is not covered by floodwaters as the Tiptonville Dome, rather than Fuller's larger area included in his egg-shaped dashed line limit. His description is as follows:

"Tiptonville Dome. From Proctor City south to Tiptonville,

the flood plain has been domed up by differential earth

movements until its elevation is 300 to 320 feet above sea

level. This domed area is not covered by flood waters."

Fick (1944) more clearly defined the geographie units and placed the Tiptonville Dome south of New Madrid and on the

Tennessee side of the Mississippi River, as he defines the

Mississippi River to be the east boundary of the Little River

Lowland south of New Madrid. On page 25 he says: "Tiptonville

Dome, south of the Cairo Lowland, is an uplifted area which lies opposite the southern end of Sikeston Ridge, but is not a

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continuation of that feature." The reason that Fisk denied a common origin between the high ground on both sides of gew

Madrid is because Tiptonville Dome is underlain by more recent meander style alluvium whereas Sikeston Ridge is under) .in 1 1 ancient braided alluvium.

Fisk stated further that the Reelfoot Lake Basin and Tipton- ville Dome are separated by a fault and assigts estimates of "uplif t" and downfaulting" as follows (p. 25) : " Maximum uplift of the

Tiptonville Dome amounts to 15 ft. judging from the displacement of stream profiles, and the Reelfoot Lake Basin is downfaulted by at least 25 ft.; hence the total displacement is as much as

40 ft." He also said of the faulting that 'he movement along

the fault was probably slow and long continued, in accordcace with Fuller's earlier conclusion for the uplift in general, so

movement in 1811-12 on the fault was slight.

The Present Writer's Use of Tiotonville Dome, Reelfoot Lake Basin, and Lake Courity Uolif t

It is clear . rom the literature review that the limits of

uplift have been variously defined by McGee, Fuller, Glenn and

Fisk. They are all essentially correct, but have used the same

name, "Tiptonville Done" in two ways. The present writer will use

McGee's original name " Lake County" for the large uplift, and Fisk's and Glenn's later restricted definition of the area of

greater uplift for the Tiptonville Dome. The basi ~ for " Lake

County uplif t" is priority for McGee's earlier (1892) work; the

jav70 0, i '

basis for restricting the name "Tiptonville Dome" is consistency.

Fuller's relationships are not contradicted. There is vari- ation and uncertainty between previous workers as to whether topography resulted from erosive or tectonic processes. This writer chooses to define them as topographic features and then consider .. ether or not they are of tectonic origin. Tiptonville

Dome is that area including the City of Tiptonville, that was not f Joded in 1937; or, where protected by levees, would not have been flooded in the absence -f levees. It is so mapped on

Figure 3 and is only one in a series of areas of high ground.

The collective name for all such features grouped into an in fe rred. larger area of uplift is the " Lake County Uplift."

Once the definition of the topographic features is made explicit, they have a useful meaning regardless of origin. Figure 3 is a map showing the various named features within the area of the Lake County Uplift and the Reelfoot Lake Basin.

The Reelfoot Lake Basin is defined a., the present of Running Reelfoot Bayou that once was occupied mainly by lakes and wetlands. Present Reelfoot Lake is only part of the basin. Before the 1811-12 carthq'zakes this area was in two separate stream drainage areas: the present Reelfoot Lake was drained by Reelfoot Creek which drained westward directly into the Mississippi River. The other is the southward flowing Obion

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Figure 3- outline map showing the topographic features con- sidered in this report that have, or may have, a tectonic origin.

f , ^jO; ) si e I 12

River , now called Running Reelfoot Bayou, which still follows approximately its original course downstream from Reel- foot Lake. A chain of lakes about 20 miles long existed here until after 1869 (Ushe7, 1837 map, and Glenn, 1869 base map in his 1933 report). South of Reelfoot Lake only remains of this old chain. Reelfoot and Isom lakes both could drain if not protected.

. . . 13

PRESENT STUDY

, The present investigation has the benefit of new data as well as information presented in previous publications. The new

data consist chiefly of (1) recent detailed 7 minute maps which

provide a better rendition of topography; (2) soil surveys (Brown

and others, 1965, 1969, and 1973) permit an inurenra*ation of the origin of surface deposit in terms of relative age (younger versus older, but dates unspecified) ; and (3) gravity surveys (including

that of the writer as part of Hildenbrand and others, 1977), which provide clues to uplifts and (4) relatively accurate location of earthquake epicenters (Stauder and others, 1976-77) which permit comparisc. of topography and soil with gravity and earth- quakes.

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14

ACKNOWLEDGME NTS

This project was mainly made possible by a grant from the U. S. Nuclear Regulatory Commission _(NRC 04-76-2 99)- to Vander- :

bilt University as part of the New Madrid Study Group. U. S. Geoloc cal Survey Regional Geophysics Branch furnished support for part of the gravity survey (Grant No. 14-08-031-G-270). Geologic Services Branch of Tennessee Valley Authority and the

Tennessee Division cf Geology loaned gravity meters. A computer- drawn gravity map was made by TVA. Much assistance in compiling flood and soil map was rendered by Phill Steidl, graduate student and Vicki Castro, undergraduate

student at Vanderbilt University. T. M. Haselton, graduate student, and Parrish Erwin, undergraduate student participated

in the gravity survey. Peggy "renne, of the Geology Department

: at Vanderbilt, compiled earthquake epicenters on a base map. The manuscript was much improved by criticism and discussion

with Stuart W. Mahe r, E. T. Luther, T. C. Buschbach, J. M.

Kellberg, and David Russ.

______1 The New Madrid Study Group is a confederation of geological surveys and universities working together on the geology and geophysics of the region with a focus on earthquakes and their e f fects . It is mainly funded by the U.S. Nuclear Regulatory Commission, and its co-ordinator is Dr. T. C. Buschbach of the Illinois Geological Survey, and St. Louis University,

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FLOOD MAPS

The Tiptonville Dome, a topographic high, was recognized by earlier workers because it has been above the greatest floods e.g. Mississippi River Commission, 1887, 1939.

The " shorelines" and altitude of islands above the 1937 flood serves to illustrate (Figure 4) the relationship of Tiptonville

Dome to the other topographic high areas. Ridgely Ridge is a southward continuation, but it is o2fset about 3 miles to the east. This map also shows that the highest part of Ridgely Ridge, about a mile northwest of Ridgely, is nearly as prominent a high as Tiptonville Dome. Tiptonville Dome is offset to the ease relative to more northern features; the west edge of Lewis Prairf. is 5 miles or so out of line with the west edge of Tiptonville

Dome. Tiptonville Dome is an uplift; it will be shown that Ridgely

Ridge is also an upllft, and if Lewis Prairie is too, then Tipton- ville Dome is the middle member of a series cf five en-echelon uplifts.

The southernmost and longest uplift is Ridgely Ridge; next the Tiptonville Dome, then the smaller Bessie and Washpan Ridges, and on the north Lewia Prairie, which is narrowly separated from

Sikeston Ridge. These were likely once all closely connected, as Tiptonville Dome and Ridgely Ridge now are; big gaps were eroded after 1811 by the Mississippi River as will be shown later. 1" Dome" in geology ordinarily signifies a structural uplift. Although the present writer defines it as a high topographic elevation, the name is retained because of long usage. If all the authors including the presentonearecorrect,}i}tQis 022 also an uplift. 16

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W [ 's f f ' [[ N E w MADRID * [ s A N ' 'N $ \ Ln 2. - t 4.J " | I ' ) " gwA $ HPAN RIDGE '

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Figure 4- Tiptonville Dome as part of a series of topographic highs, which are drawn as islands during a flood like that of 1937 to an elevation of about 298 at mile 900.

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UPLIFT OF TIPTONVILLC Dome, RIDGELY BIDGE, AND BESSIE RIDGE

AS JUDGED FROM SOIL MAPS AND TOPOGRAPHY

Areas underlain by soil with a B-horizon probably stopped receiving sediment before areas underlain by soils lacking a

B-horizon. Figure 5 delineates areas with soils having a B-horizon and Figure 6 shows the surface elevation of these soils. See

Table 1 for a list of soils with "B" horizons. Both high and low ground have so'ls with and without B-horizons. Where soils lack- ing B-horizons occur on high ground, it is possible that sediment at the land surface was deposited on lower ground a relatively short time ago and since uplifted.

In the Reelfoot Lake Basin, soils with B-horizons occur on low ridges nearly at lake level (ele ; ion 283 feet). Between

Reelfoot Lake Basin and the Tiptonville Come, the elevation of these soils is from about 315 feet on the dome to 280 feet (or lower if any of the soils lie buried beneath lake mud) in the basin -- a dif ference of 35 feet (or more). If as a basis for calculation, this surface can be considered to once have been nearly flat, the present 35 foot (or - ater) difference is con- sistent with Fisk's (1944) estimate from drill data of 40 feet of vertical fault offset between these two areas.

------

1 In the (Jure 1977) USGS-Vanderbilt trench on the Tiptonv.mle Dome, two samples of gastropod shells from about 8 feet below the land surface on the Tiptonville Dome gave radiocarbon dates of about 1203 to 1603 years b.p. If these dates are correct the uplift

has been at least 20 feet or so in about 1400 years. ~ b, ,!. ! "b a ufl 18

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Figure 5- Soil Map showing areas underlain by older soils, as judged from their having a B horizon. These older soils probably differ from each other in age by many hundrede r thousands of years, but they are likely to be collectively older than the other soils on the alluvial plain without "B" horizons. For a list of the soils having "B" horizons see Tablo 1.

'

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19

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Figure 6- Elevation of the areas shown on Figure 5 to be underlain by older soils. p q f., IT G c. V 7) JV's 20

TABIE 1

SOILS IN THE STUDY AREA THAT ARE DESCRIBED AS HAVING A "B" HORIZON. THESE UNDERLIE THE STIPPLED AREA ON FIGURE 5 IN DYER, LAKE AND OBION COUNTIES, TENNESSEE

Which County or Series Name Counties Comment 2 Alligator Dyer County Not mapped in Lake or Obion Cos. Bosket Dyer County Not mapped in Lake or Obion Cos. Commerce Obion County In Lake and Dyer Cos. this soil is mapped, but is tPere described as having no "B" horizon

Dubbs Dyer County Not mapped in Lake or Obion Cos. Dundee Dyer Co. Not mapped in Lake or Obion Cos. Forestdale byer and Obion Cos. Not inapped in Lake County Iberia Lake and Obict Jos. Not mapped in Dyer County Reelfoot Lake and Obion Cos. Not mapped in Dyer Cc ty Sharkey Obion County In Lake and Dyer Cos. this soil is mapped, but is there described as having no "B" horizon Tiptonville Lake and Obion Cos. Not mapped in Dyer County Worthen Lake and Obion Cos. Not mapped in Dyer County

1 Brown and others, 1965, 1969, 1973.

2 Dyer County was mapped and published first, so some coils mapped there are probably similar to those given other names later in Lake and Obion Counties.

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21

TOPOGRAPHIC ENVELOPES

General

An envelope is a devi:e useful to generalize topography

and restore local eroded areas by graphically filling in de-

pressions. Because relief is so low on most of the alluvial

plain, envelopes, though they represent considerable straighten-

ing cf contour lines, either touch or stay within a couple of

feet of the land surface. Stearns (1967) used such envelopes

to describe the dissected Western Highland Rim plateau surface

in Tennessee and readers are referred to that paper for a de-

tailed description of the method.

The use of envelopes is preferable to some averaging

technique, precisely because envelopes emphasize high points.

In this study the metnod served best to partially restore eroded

topographic highs near the river. The shape of the land surface

as generalized by envelopes will be examined for patterns of

vertical movement.

-r pqp )J U L. d 22

Detailed Topographic Envelope (Figure 7 )

Figure 7 is a contour map of an envelope closely approxi- mating the topography. It touches the ground at points no more than 2000 feet apart, and generally closer than 2000 feet apart.

The topographic highs already described are well displayed to- gather with some curious trends west of the Mississippi River where the ground surface is nearly flat. The 280-foot contour

line though having small deflections, makes a distinct :" with its base extending roughly from Portageville, Missouri southeastward; its diagonal runs north northeast from Portage- ville about 14 miles toward the west edge of Sikeston Ridge where it turns west parallel to the base. This trend appears to be anomalous, it would be expected that 5-foot contours would trend westward, as do the 50-foot contours on AMS 1:250,000 maps (e.g. on the Dyersburg 2 degree sheet, north of the area shown on Figure 2, the 300-foot line trends west 25 miles from

East Prairie to Dexter). The feature defined by the "Z" contour configuration will be referred to below as the "Portageville

Bulge."

Generalized Topographic Envelope (Figure 8)

Figure 8 is a more generalized topographic map. (The part of the map to the north and west, not on Figure 7, was made from

15-minute topographic maps rather than the 7 1/2-minute maps used for Figure 7.) This map is also an envelope, but is more gener- alized as it touches the ground at points spaced 1.5 miles qq ., g io c. ' })J V 23

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Figure 7- Detailed Configuration of the alluvial plain of the Mississippi River in the Study Area (in the east part of the Eastern Lowlands). This is an envelope over the surface that touches every 2000 feet of closer. Arrows are put on the 280 foot contour line to show its "Z" shaped trend.

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Pigure 8- Generalized configuration of the entire width of the Eastern Lowlando 'he alluvial plain of the Mississippi River. This map is an envelope on the surface that touches every mile and a half or closer. The spacing permits contour lines to " jump across" the Mississippi River. Arrows are put on the 280 foot contour line in the same position as those on Figure 7 330 0 .'. 3 25

apart or closer, generally closer. The features seen on Figure

7 are apparent here, too. The "Z" shape mentioned for the 280-

contour line on Figure 7 occurs on Figure 8 for all contours

from 275 to 290 feet. This pattern extends westward for 8 to

16 miles to the scarp at the edge of the Malden Plain. The

set of east-west-trending contours just east of Malden scarp

will be used as an arbitrary datum for comparison. This lower

ground includes areas said by Fuller to have been " sunk," in

1811-12 but the sinking was disputed by Saucier (1970). Saucier's

conclusion is arbitrarily accepted to permit a quantitative

basis for comparison.

The eastern part of Missouri on Figure 8 displays a dis-

tinct rectangular southwestward-trending gentle " bulge" of the

' alluvial plain. Its west edge is shown by the diagonals of the

"Z" contours bearing about south 40 degrees west from near

Lilbourn (at the west edge of Sikeston Ridge) a distance of

some 12 miles (as measured from the 280-foot contour line bend).

This squarish bulge (Portageville Bulge) is believed by the writer (in accordance with the general conclusions of McGee and

Fuller) to be the western and southern fringe of the Lake County

Uplift, which is less uplifted (roughly 10 feet) compared with

the land farther west below the Malden scarp.

O '? ? 3sv7O vsu 26

MODERN EROSION OF THE TOPOGRAPHIC HIGHS

Fisk (1944, Plate 22) has precented historic river courses back to 1765 as well as more ancient ones. Using only the com- bined belt of the historic courses (Figure 9) we can see where the topographic highs could have been much eroded. Figure 10 shows that the north edge of Tiptonville Dome and east edge of

Bessie Ridge could have been connected in 1765 with about 6 square miles of high ground that has since been eroded. The east side of Lewis Prairie has been eroded back two miles or so by the river since 1765, opening an original smaller gap to the present 2 miJes between Washcan Ridge and Lewis Prairie.

Figure 10 suggests a probable chain of topographic highs from Sikeston Ridge in Missouri, 25 airline miles, to Ridgely in Tennessee with erosion partially restored so that gaps between tN'em are a mile or less. This could have been the situation in

1812 immediately after the earthquake.

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Figure 9- Area occupied by channels of the Mississippi River since 1765, and the areas where lateral erosion has

likely destroyed part of the Tiptonville Dome t.ndi Lewis Prairie. i , p , 'A h a (d Gst 28

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Figure 10- The flood islands as they may have been in 1812 (restored for likely post-1765 lateral river erosion). Dashed lines show estimated extensions. 29

RELATION TO DEEPER _ STRUCTURE

Evidence from Gravity Anomaly Data

A gravity survey with about a 1-mile spacing of stations, and about 0.2 milligal or better accuracy has been made of the

Tiptonville Dome, Ridgely Ridge, and Reelfoot Lake areas in

Tennessee (Figure ll) . Tiptonville Dome and Ridgely Ridge are on or near Lne crest of a north-trending elongated positive

Bouguer gravity anomaly. The sources for such an anomaly are likely to occur only below the Cretaceous, at least 3030 feet deep and perhaps at earthquake focal depth. This relationship supports the conclusion that topographic features in Tennessee are deep seated structures. They are therefore not some dis- cordant surface ef fect such as wrinkling during lateral shift of soft surficial deposits (as suggested by Fuller, 1912), or catastrophic local compaction of soft clays (as suggested by

Glenn, 1933, for the Reelfoot Lake sunk area).

Evidence from Ear _thquake Epicenters

comparison of earthquake epicenters (Figure 12) with the pattern of uplifts as proposed herein shows that the south end of Ridgely Ridge in Tennessee and Lewis Prairie Ridge in Missouri have many epicenters. This is a partial coincidence, because fewer earthquakes do occur on other similar features; for example only two occurred under the Tiptonville Dome, and only two have occurred near Washpan Ridge.

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n '!. ~ ,, (T '. fJ Figure 11- Bouguer gravity anomaly map of the Tiptonville Dome, Ridgely Ridge and Reelfoot Lake area. Contro? (not shown) consists of about 800 obser- vatior. points. The flood islands are shown by the r, tippled pattern. 31

m, , ' erse ' 8995' e . \ + ++ y g p'8si r u noRio y , , 44++ "t.o. . */ +++++44 ff .' + - ++ + & + ' , . & ' ' + 444 ++ , e + ++ + + +4t4,+1' , E, 4 + g. . 2, 4 t '+-\ '+ ' d '. ny ' '' -' > -4 .fi 4 - =f ' 7g,, 3s se ' I , - ' ' ++ +dt -t +++'-1) ) + m .. / ' ' + + + + + + - +++ - / + + + d [ t+ + s . + + 5;o s 4 i +t- ++ + f - + + t +++ '- TIP N VIL L E [ + tt 4+ / + + r~ -M + + ! ; ++ r| ! 4 + 4+! 4-[4J / + + -- - + +r' / 'Q ++ 4+ +--+ - -+ + ) - WO F r;~ N .4 4 . + d +f f / ' * ' ' ' \ + ~- \+ r+ 4 + , +-- ' + + + , + dy,__.'*

Figure 12- Earthquake epicenters in Lake County Tennessee, and vicinity June 30, 1974 to Jun. 30, 1977 (from Stauder and others Southeast Missouri Regional Seismic Network Quarterly Bulletins). Earthquakes south or west of Caruthersville or north of New Madrid are not shown. Flood islands are shown Ff the stippled pattern. LU 038 32

Earthquake locations suggest that the south edge of the uplift is a zone of recent movement. A line of earthquakes trending from near Dyersburg through Miston and northwestward across the Mississippi River toward Portageville is precisely on the trend of the 280-foot contour line (which topographi- cally defines the trend of the south relatively straight edge of the Lake County Uplif t. Continuous microearthquake activity suggests that uplift may occur gradually, and that only part of it may have been accomplished during major earthquakes.

plQ ,) Jn ' J' 33

CONCLUSIONS

Tiptonville Dome, a topographic high long recognized as a tectonic uplift, is seen to be part of a 20- to 25-mile long series of topographic highs. This series of topographic highs extends northward from Ridgely Ridge in southern Lake County,

Tennessee, into Missouri at Lewis Prairie, a southwest tip of

Sikeston Ridge. Though now separated by a gap of nearly 3 miles near New Madrid, in 1765 the topographic highs probably were nearly continuous, separated by gaps of only about a mile. Rec- tangular trends of contour lines in Missouri and southern Lake

County, Tennessee define a squarish slightly high area, called the Portageville bulge. This feature could well be tectonic and raised with the ridges. The bulge, together with the ridges, are collectively classified as the Lake County Uplift of McGee (1892).

The ridges in Tennassee coincide with positive gravity anomalies. Thus, these topographic features in Tennessee are surface manifestations of deep seated tectonic movements. Be- cause small earthquake epicenters are abundant on parts of the uplifts and in the vicinity of uplift boundaries, the uplift may be a continuous phenomenon, only part of which occurred during major earthquakes such as the 1811-12 series.

330 0"0 TABLE 2 HOW DEFINED LIKELY APPROX. VERTICAL FEATURE AND MAPPED ORIGIN (S) MOVEMENT E3TIMATES B AS IS FOR ESTIMATE * RIDGELY Flord Island Tectonic Uplift UP 20-25 r". (6 to 8 m) from Reelfoot Lake RIDGE Topographic may be nearly origina1 shape UP 5-15 (2 to 5 m) from Miss. River flood *

TIPTONVILLE Flood island Tectonic Uplift UP li Feet (5 m. ) from Uplifted stream pro- DOME Topographic now carved on N files (Fisk 's (1944) & W side by later- estimate (relative al river erosion to flood level) UP 35-40 Ft. (11 to 12 m) f r im Reelfoot Lake (elev. 283) UP 10-20 Ft. (3 to 6 m) from Miss. River flood

BESSIE RIDGE A chain of Tectonic Uplift UP 15-20 Ft. (5 to 6 m) from Reelfoot Lake and flood maybe mostly WASHPAN RIDGE islands destroyed by UP 2-10 Ft. (1 to 3 m) from Miss. River flood Topographic lateral erosion

LEWIS PRAIRIE A flood Possibly a lesser UP 5 Ft. (2 m) from Reelfoot Lake y Island tectonic uplift maybe 1/3 de- UP 5 Ft. (2 m) from Miss. River flood stroyed by lateral river erosion

REELFOOT Low wetland & Tectonically sunk DOWN 2 to 10 Ft. (1 to 3m) 1.elow present lake water LAKE BASIN adjacent '. ow or left behind as level, Fuller's area adjacent land was (1912) estimate Topograpl uplifted farther. Maybe nearly original shape t;l DOWN 25 Ft. (8 m) Offset from Drilling, ' L Fisk's (1944) estimate. CT' (re l . to flood a strata on Tiptontille c; Dome, see above)

.s

6 TABLE 2 (Cont'd)

HOW DEFINED LIKELY APPROX. VERTICAL BASIS FOR ESTIMATE FEAT URE AND MAPPED _ ORIGIN (S) MOVEMENT ESTIMATES from Usher (1837) account PORTAGEVILLE Topographic Tectonic up- UP "only a few feet" in BULGE squarish shape lift & maybe 1811-12 along river anomaly partly a con- on Tennessee side, and s tructiona l enough to dry up feature Portage Bayou in from Lyell (1846) deposited by Missouri Mississippi River Maybe nearly original shape 3 UP 0-5 Ft. (0-2 m) from Reclfoot Lake

______w w * Estimates of uplift relative to Reelfoot Lake are the pre ferred estimates. They come from com- paring contours on Figure 8 with elevation 283, the spillway level of Ree foot Lake. If it is desired to estimate uplift relative to the pre-1811 small slough at Reelfoot Lake, add 2-10 feet (1-3 m) to uplift estimates. L-Uplift relative to a flood datum come from contours on Figure 5. L- CZ)

CD h. IV 36

REFERENCES CITED

Brown, William T., Moffitt, William C., Moore, Charles L., and Jackson, Wesley C., 1965, Soil Survey of Dyrr County, Tennessee, U. S. Department of Agriculture Soil Conservation Service, in cooperation with Tennessee Ag. Exp. Sta., 79 p., 65 maps. Brown, William T., Jackson, W. C., Keathley, G. L., and Moore C. L., 1969, Soi] Survey of Lake County, Tennessee, U. S. Department of Agriculture, Soil Conservation Service, in cooperation with Tennessee Ag. Exp. Sta., 39 p., 19 maps.

Brown, William T., Jackson, Wesley C., Keathley, Glisson L., and Moore, Charles L., 1973, U. S. Department of Agriculture Soil Conservation Service in cooperation with Tennessee Ag. Exp. Sta., 60 p. 71 maps.

Fisk, Harold N., 1944, Geological investigation of the alluvial valley of the Lower Mississippi River, U. S. Army Corps of Engineers, Mississippi River Commission, Vicksburg, 78 p., 33 Plates including map of 20 old courses of the Mississippi River, and many others.

Fuller, M. L., 1912, The New Madrid earthquake: U. S. Geological Survey Bull. 494, 119 p.

Glenn, L. C., 1933, The geography and geology of Reelfoot Lake: Tennessee Academy of Science Journal, v. 8, p. 3-12.

Hildenbrand, T. G., Ervin, C. P., Hendricks, John, Keller, G. R., McGinnis, L. D., and Stearns, R. G., 1977, Bouguer gravity map of the northern Mississippi Embayment, parts of Missouri, Arkansas, Tennessee, Kentucky and Illinois, scale 1:500,000. Krinitzsky, E. L., 1950, Geological investigation of faulting in the Lower Miss.ssippi Valley, Corps of Engineers, U. S. Army Technical Memo No. 3-311, Waterways Experiment Station, Vicksburg, 91 p.

Lyell, Charles, 1849, "A second visit to the United States: Vol. 2, Harper and Brothers, New York, 287 p. McGee, W. J., 1892, "A fossil earthquake": Bull. Geol. Soc. Amer., Vol. 4, p. 411-414.

Mississippi River Commission, 1887: Map of the Alluvial Valley of the Mississippi River from the Head of St. Francis Basin to the Gulf of Mexico Showing Lands Subject to Overflow, Location of Levees and Trans-Alluvial Profiles: scale 1:316,800. K ~7 p po7 JJv G^N 37

Mississippi River Commission, 1939; St. Francis Basin of the Alluvial Valley of the Mississippi River: Corps of sngineers, U. S. Army, scale 1:250,030.

Saucier, R. G., 1970, Origin of the St. Francis sunk lands, Arkansas and Missouri: Geol. Soc. Amer. Bull., v. 81, p. 2847-2854 Stauder, William, Schaefer, Stephen, Woods, Marie, Cheng, Shiang-ho, and Morrisey, Sean Thomas; Southeast Missouri Regional Seismic Network; Quarterly Bulletin No. 10, 1 Oct.-31 Dec. 1976, St. Louis University, 23 p. This is one of a continuing series.

Stearns, R. G., 1967, Warping of the Western Highland Rim peneplain in Tennessee by ground-water sapping, Geol. Soc. Amer. Bull. v. 78, p. 1111-1124.

Usher, F. C., 1837, on the elevation of the banks of the Mississippi in 1811: Sillimans Journal ( Am. Jour. Sci.,.First Series), v. 31, p. 294-296.

330 Oc4 #O " " U.S. NUCLE AR REGUL ATORY COMMIESION O '# BIBLIOGRAPHIC DATA SHEET 4. TITLE ANO SUBTITLE (Add Volume No., if epreneof 2. (Leave blai&/ Rtcent Vertical Movement Of The Land Surface in The Lake County Uplift and Reelfoot Lake Basin Areas, Tennessee, 3. RECIPIENT 3 ACCEsslON NO. Missouri and Kentucky. _ 7. AUTHO R(s) 5. DATE REPORT COMPLETED Richard G. Stearns M ON TH |vEAR March 1979 9 PE RFORMING ORGANIZATION N AME AND M AILING ADDRESS (/ne/ var 2,p Coorf DATE REPORT issued MONTH YEAR Vanderbilt University

Department of Geology 3 ft ,,,, ,,, ,; Nashvi I le, Tennessee 37235 8. (Leave Nank)

12. SPONSORING ORG ANIZ ATION N AME AND M AILING ADDRESS (/nclude Zip Codel 10. PROJECT / TASK / WORK UNIT NO. U.S. Nuclear Regulatory Commission Division Of Reacter Safety Research ti. CONTRACT NO. Washington, D. C. 20555 tRC-04-76-299

13. TYPE OF REPORT PE RIOD COVE RE D (/nclusive dams) Technical March 1978 - March 1979

15. SUPPLEMENTARY NOTES 14. (Leave Nm1*/

16. ABsTR ACT C00 words or tessl Tiptonville Dome, an established tectonic uplifk, is one in a 20 mile series of en echelon topographic highs, most or all of which are upilfts. These f eatures are too high to have been flooded during the largest historic floods, During these floods they were temporary Islands. From Lewis prairie, at New Madrid in Missour i, five such topographically high areas extend southward across the Mississippi River to RidgelEy, Tennessee. Although separated now due to modern erosion, they were nearly continuous in 1811. Contour trends reveal q squarlsh topographic bulge west of the " flood Islands", the western corner of which is near Portageville, Missouri. It may have been uplittedwith, but less than, the "finod Islands." This bulge and the topogra )hs highs comprise the Lake County Uplift.

17. KE Y WORDs AND DOCUMENT AN ALYsis 17s. DEsCRIPTORs

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17b. IDENTIFIE Rs/OPEN-ENDED TERMS

19. sECURI Lass (This report) 21. NO. OF PAGEs 18. AV AILABILITY ST ATEMENT Uncl ss ed NTIS-NRC RAR6 +50 Copies f or Contractor + 50 Copies 2 g g g yf g trnespap) 22 PRICE f or N. N. Steuer f or internal distribution s NRC FORM 335 (7 77) UNITE D ST ATE S NUCLE AR R E ".i U L A T O R Y COMMs55 TON f ~] W ASHING TON. D. C 20S55 postage Ano e e r s esio gL p V s NUC LE A R RE GUL A TOR Y OF f ICI AL SUSINF 55 [g C o u w s ssio N P E N A LT Y F O R PRIV A T E USE . $ 300 L"J

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