GEOLOGICAL INTERPRETATION OF LANDSAT IMAGERY

FOR THE SANDHURST ROXANA EXPLORATION PERMIT

NEAR

FLAT BAY, NEWFOUNDLAND

December 1995

By

Frederick N. Murray

Consulting Geologist

TABLE OF CONTENTS

PAGEINTRODUCTION .........................................…………………. 1

LANDSAT SCENE............................................………………. 4

STRATIGRAPHY........................................…………………… 5

STRUCTURE..............................................…………………... 7

STRESSED VEGETATION......................................…………. 20

CONCLUSIONS.............................................………………… 22

SELECTED BIBLIOGRAPHY.....................................……… 24

LIST OF ILLUSTRATIONS

FIGURE PAGE

I. Index map of Newfoundland illustrating the location of Exploration Permit 93-101 ..............…………… 2

2. One-quarter Landsat scene centered at approximately 580 411 West Longitude and 48° 22’ North Latitude ………………….............................. 13

3. Landsat true--color image of Exploration Permit 93-101 .................................……………………..... 14

4. Landsat infrared image of Exploration Permit 93-101 ...................................……………………... 15

5. Landsat infrared image of Exploration Permit 93-101 illustrating important geological information .........................…………………..... 16

6. Landsat, Kauth-Thomas transformation image of Exploration Permit 93-101 ..........…………......... 17

INTRODUCTION

This report on Landsat imagery is written at the request of Mr.Gary Johnson of Sandhurst Roxana Exploration Ltd., P.O. Box 2707,Tulsa, Oklahoma 74101. The study includes the area of ExplorationPermit 93-101, Department of Natural Resources, Government ofNewfoundland and Labrador, and surrounding areas.The northern boundary of the Exploration Permit lies 2 kilometerssouth of Flat Bay, Newfoundland, a coastal town on the southeastside of St. George's Bay. Essentially the permit area is a square 20kilometers on a side, excluding the oceanic area of the northwestcorner, and containing approximately 36,000 hectares (89,000 Ac).The permit is located on the basis of Universal Transverse MercatorGrid with the southeast corner of the 20 kilometer by 20 kilometerpermit placed at reference point 390000 m East and 5340000 mNorth. The permit boundary is aligned with the UTM grid. Anapproximate location for the southeast corner is 58° 12.5' WestLongitude and 48° 29’ North latitude. Thirteen kilometers of Atlanticcoastline delineate the northwest corner of the Permit (Figure 1).

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Figure 1. Index map of Newfoundland illustrating the location ofExploration Permit 93-101.

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The purpose of this report is to evaluate Landsat imagery andrelate it to surface geology in order to determine the petroleumpotential of Exploration Permit 93-101. The imagery also providesinformation on roads and vegetation cover. Vegetation is important inthat it relates to surface geology and accessibility for seismic crewsand other equipment. Information for this report was interpreted fromLandsat imagery or obtained from various geologic literature sources.No field check or ground truthing was accomplished.The Department of Natural Resources, Government of

Newfoundland and Labrador at St. John's Newfoundland werehelpful in locating information, references, and maps for this report.Messieurs Ian Knight and Dave Hawkins were most helpful in thisrespect. Also, Mr. Fred Thistle, Forestry Management Division of theDepartment of Natural Resources, Corner Brook, Newfoundland, wasvery helpful in furnishing forest inventory maps which were used asan aid for interpreting landsat imagery.

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LANDSAT IMAGERY

The Landsat imagery of this report was purchased fromradarsat, 3851 Shell Road, Suite 200, Richmond, British Columbia,Canada V6X 2W2. A one-quarter scene dated August 9, 1991 was

chosen to avoid winter snow conditions and place emphasis onthe "leaves on trees" growing season-when stressed vegetationwould be most evident. The region covered by the one-quarter scenewas centered at approximately 580 411 West Longitude and 48'D221 North Latitude and covered an area 88 kilometers (north-south)by 92 kilometers (east-west). A few small cumulus clouds werepresent in the southern part of the one-quarter scene, but none withinthe Exploration Permit area (Figure 2). Landsat imagery was receivedfrom Radarsat in digital form in order to process the one-

quarter scene by computer. A path oriented image wasrequested from Radarsat to eliminate any possible loss of resolutionwhich could occur with reprocessing of data values. The one-quarterscene is a part of full Landsat scene which has the generaldesignation of Row 26, Path 05.

The Landsat data was received from Radarsat in the form of asingle CD-ROM disk containing Landsat-5, Thematic Mapper, digitaldata. The data consisted of a full set of seven Thematic Mapperbands for each pixel. Three of the bands are in the visible part of thespectrum and represent colors; blue, green and red. The infrared partof the spectrum is represented by three bands; one near-infrared andtwo middle-infrared. One band records how objects radiate heat andis referred to as the thermal band.

The imagery was viewed on a Viewsonic 17G, 1280 X 1024,monitor; using a 486/33DX central processing unit; with a 540megabyte hard disk drive; 8 megabyte RAM; and other appropriatehardware. ERDAS 7.5 software was used for processing the Landsat,Thematic Mapper, digital data using various combinations of bandsand band ratios.

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STRATIGRAPHY

The Exploration Permit of this study lies within the Bay St.George subbasin which formed during the late Devonian andCarboniferous time. The part of the subbasin that is currently on landis roughly 125 kilometers long and 25 to 30 kilometers wide andparallels the western coast line of southwestern Newfoundland. Thisland area portion of the subbasin extends from Cape Anguille at thesouthwest end to approximately 25 kilometers northeast ofStephenville Crossing, Newfoundland at the northeast end. A part ofthe subbasin probably lies beneath St. George's Bay wheredeposition of sediments occurred as the basin opened-up during andafter Late Devonian.

Sedimentary rocks of the Bay St. George subbasin are knownto range in age from Late Devonian through Carboniferous. The threeintervals of strata deposited in the subbasin from lowest to highestare the Anguille Group, the Codroy Group, and the Barachois Group.Original thicknesses of these three groups in the Flat Bay - Barachoissynclinorium area are approximated to be: 2,700 feet, 7,500 feet, and6,000 feet, respectively. However, the maximum thickness of thecombined intervals along the axis of the Barachois synclinarium isestimated to be 13,500 feet. The thickness of strata exposed abovebasement rock along the axis of Flat Bay anticline ranges from anestimated 600 feet at the south end to 0 feet at the north end. TheFischells conglomerate of the Anguille Group unconformably overliesbasement rock along the axis of the anticline. A distinction betweengroups of strata and formation boundaries could not be definitelymade by Landsat imagery.

However, the bedded gypsum and possible rock salt depositsof the Codroy Group often displayed lakes, sinkholes, and anirregular vegetation areas which could be traced on the imagery. Thisevaporitic strata of the Codroy Group forms an outcrop belt .5kilometer to 1.25 kilometer in width along both flanks of Flat Bayanticline.

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Sedimentary rocks in the Bay St. George subbasin consistprimarily of continental deposits. Marine sedimentation is associatedwith deposition of evaporates in the lower part of the Codroy Group.The Anguille Group is make up of redbeds, sandstone, conglomerate,shale, and mudstone of fluvial, deltaic, lacustrine, and alluvial fanorigin. The Codroy Group consists of gypsum, rock salt, limestone,siltstone, sandstone, conglomerate; and redbeds of evaporate basin,shallow marine, deltaic, and fluvial origin. The Barachois Groupconsists of typical Middle Pennsylvanian strata (Westphalian). It ismade up of sandstone, siltstone, shale, thin coal beds, and localconglomerates deposited in fluvial and shallow swamp environments.

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STRUCTURAL GEOLOGY

The Long Range fault, a possible extension of the Cabot fault,bounds the Bay St. George subbasin on most of the southeast side.The up-faulted Steel Mountain anorthosite bounds the basin on thenorthern part of the southeast side. Structurally, the subbasin has hada long developmental history, starting with basin filling and formationduring Late Devonian and culminating in Late Carboniferous withmoderate to strong deformation of the subbasin strata to form manyof the evident structural features. Movement along the Long Rangefault has been varied. Vertical movement is associated with basinfilling and right-lateral wrench fault movement is associated with thedeformation of the subbasin.

Knight (1983, p. 273-287) discusses the structural geology ofthe Bay St. George subbasin and relates faulting and folding of thebasin strata to right-lateral 'wrench fault movement on the LongRange fault. The Long Range fault is considered to be the mainregional fault to which subsidiary deformation can be related. In thewrench fault system, the synthetic faults encounter the main fault atan angle of 00 to 250. The Crabbes Brook fault, and the Snakes Bightfault are considered to be examples of synthetic faults. These faultsdemonstrate right-lateral displacement. Antithetic faults occur inassociation with deformation of the Anguille anticline in the southernpart of the Bay St. George subbasin. None of the antithetic faultshave been definitely identified in the Exploration Permit area or thegeneral vicinity as illustrated in Plate 1. Where antithetic faults arepresent, in the southern part of the subbasin, they form an acuteangle of 600 to 70'D with the synthetic faults and their movement isleft-lateral in relation to the long Range wrench fault which is right-lateral.

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Several east-west lineaments observed on Landsat imagerycross the Bay St. George subbasin. The lineaments are relativelystraight line-like features which are believed to be structurallycontrolled. These lineaments are probably faults; however, specificdisplacements could not be identified from Landsat imagery. All ofthese lineaments, with the possible exception of the Dribble Brooklineament, seem to extend westward beyond the current coast line ofSt. George's Bay. The presence of a major fault paralleling the coastline a few kilometers seaward from the coast line has been inferred tobe present (Webb, 1969, p. 775;

Belt, 1969, p. 745; Langdon and Hall, 1994, fig. 5). This fault iscalled the St. George's Bay fault. It crosses the north coast line of St.George's Bay on the east edge of the granitic and mafic rocks of theIndian Head Range complex (Geological map of Newfoundland,1955, 1967) and extends to the northeast on a N 450 E trend.Landsat imagery confirms the trend on land but only the coast line atBank Head and a parallel relationship with the shore line seem tocontrol the direction to the southwest in the bay area.

From north to south, the trends of the lineaments and theirangular relationship with the St. George's Bay fault are as follows:

Angle withSt. George's

Trend Bay Fault

Flat Island lineament N 65° E 20°

Little Barachois Brooklineament N 75° E 30°

Dribble Brook lineament N 75° E 30°

Journois Brook lineament N 80° E 35°

Rattling Brook lineament N 80° E 35°

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Big Otter Pond lineament N 90° E 45°

Mitchells Pond lineament N 90° E 45°

Shoal Point lineament N 90° E 45°

The northern five lineaments are relatively straight. However,the southern three lineaments curve toward the Long Range fault withtrends of S 80° E when approaching the fault. In the case of the OtterPond lineament and the Mitchells Pond lineament the curve reversesto a trend of N 80° E at intersection with the Long Range fault.

The following indicators are used to identify lineaments:

1. Chains of lakes.

2. Elongated lakes.

3. Promontories or embayments in lake shore-lines thatsuggest fault location.

4. Changes in stream direction.

5. Constant direction for a stream over a kilometer or more.

6. Fault scarps.

7. Change in stream appearance from meandering to braided.

8. The presence of bays and coves along the southeast coast line of St. George's Bay.

The bay and cove coast line, which is considered to be anindicator, is in marked contrast to the straight, smooth coast formedalong the northwest side of the Anguille Mountains immediately to thesouth.

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The lineaments may be the east-west trending faults ofLangdon and Hall (1994, p. 1760-1761) that have been recognized bymarine seismic work in the Cabot Strait and St. George's Day. Belt(1969, p. 743-744) presents evidence for a major east-west trendingfault at locality "W” on his map, which seems to correspond with theShoal Creek fault and Shoal Creek lineament. Aeromagnetic data aresaid to indicate a major east-,west structure at this locality.

Three explanations for the series of eight lineaments are offered.

1. The lineaments could be a series of splay faults off the St.George's Bay fault or

2. The lineaments are synthetic faults caused by right- lateral movement on the St. George's Day faults or

3. The lineaments are east-west faults, some of which have been reoriented. In this case lineaments are considered to be unrelated to wrench fault movement.

None of these explanations seems to fit the geometry offaulting. However, deformation of the subbasin has been long andcomplex and it is suggested that a combination of these explanationswould be the best fit.

The Crabbes Brook fault (Knight, 1983, fig.42) bounds theBarachois synclinorium on the northwest side. Only very minimalevidence for this fault could be identified on Landsat imagery. Also,en echelon folds and other surface mapped faults (Knight, 1983,geologic map) in the Barachois synclinorium were not evident onLandsat. The northern end of the Snakes Bight fault and the axis ofthe associated anticline were readily identifiable by topography andimagery.

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Lineament trends are generally evident in the color patterns ofthe Landsat imagery. Figures 2, 3, 4, 5, and 6 illustrate images withdifferent band arrangements, using the three principal colors of red,green, and blue (RGB), to generate the colored image. Selection ofthe bands to be used for red, green, and blue is arbitrary. However,three numerical values must be scaled, one for each of the threeprincipal colors. Three principal color values are used for each pixelin order to generate the raster image which is made up of all thepixels. Algebra computations may be used in various ways to createthe three numerical values used. Obviously, there are a great numberof colored images which can be created. Those images which portraythe geology best are those sought after for interpretation.

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Figure 2. One-quarter Landsat scene centered at approximately580 411 West Longitude and 48° 22, North Latitude. The areacovered is 88 kilometers north-south and 92 kilometers east-west, with north toward the top of the photograph. This is atrue-color image made by combining TM-5 bands 3, 2, 1 (RGB).Date: 8-9-91.

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Figure 3. Landsat true-color image of Exploration permit 93-101Photograph illustrates: forest and vegetation, green; bogs,grayish-purple; fresh water lakes, black; gypsum mine, 'whitearea at top--center; anorthosite, gray nobs in upper right corner;and Trans-Canada highway, white line. TM-5 bands 3, 2, 1(RGB). Date 8-9-91.

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Figure 4- Landsat infrared image Of ExpIoration permit 93-101.Photograph illustrates-, healthy vegetation, various shades of red;stressed vegetation, dark green; and various roads and tracks, paleblue lines. TM-5 bands 4, 3, 2 (RGB). Date: 8-9-91.

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Figure 5. Landsat infrared image of Exploration Permit 93-101illustrating important geological information. Photographillustrates: Dribble Brook lineament, DB; Journois 'Brooklineament, JB; Rattling Brook lineament, RB; Otter Pondlineament, OP; Mitchells Pond lineament, MP; Long Rangefault, LR; Crabbes Brook fault, CB; stressed vegetation, SV;Anorthosite, A; and evaporitic strata of Codroy Group, E. TM-5bands 4, 3, 2 (RGB). Date: 8-9-91.

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Figure 6. Landsat, Kauth-Thomas transformation image ofExploration Permit 93-101. Stressed vegetation forms the darkbrown area in the center of the photograph. The image isdetermined by a so called "tassel cap" transformation in whicheach principal color (RGB) is determined by its own individualequation with the solution to each equation being a function ofthe six Landsat reflectance band values. This image displayssoil brightness. Date: B-9-91.

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Figures 2 and 3 illustrate the Exploration Permit area andvicinity in true-.color. Figures 4 and 5 illustrate infrared imagery withthe positions of important geological features and stressedvegetation. Figure 6 illustrates a tasseled cap transformation imagewhich seems to show stressed vegetation as well as soil brightness.

The most evident fold in the Exploration Permit area is Flat Bayanticline. This anticline is 25 kilometers long and 7 kilometers wide. Ittrends N 40'0 E and roughly parallels the St. George's Bay coast line.The anticline is separated into a northern dome and a southern domeby two lineaments which cross the anticlinal axis at acute angles ofabout 40(. Landsat imagery displays a sequence of lakes, sink holes,and vegetation variation which follow the outcrop of the CodroyGroup evaporates around the flanks of the anticline. Strata dips onthe flanks of the anticline have been reported by Knight (1983,geologic map) to be in the order of 15 to 30 degrees with a scarcity ofattitudes along the axis of the anticline where the Fischellsconglomerate crops out. In places flank dips of 40 to 50 degrees havebeen reported. The anticline is doubly plunging; however, no specificinformation on the angle of plunge is available.

Basement rock of probable Precambrian age has been reportedat the center of the northern dome of Flat Bay anticline. Knight(1983, geologic map) illustrates an outcrop of pre-Carboniferousbasement centering the northern dome which is 4 to 5 kilometers longand l ½ kilometers wide. A single attitude on foliation was evidentlymeasured in this basement rock. This basement rock is considered tobe Grenvillian, of Late Precambrian age (Knight, 1983, p. 13). On hismap, Belt (1969, p. 743-744) indicates basement rock crops out atlocality "X” (northern dome) and that only a few hundred feet ofconglomerate are present above basement at locality 'IF" (southerndome) according to aeromagnetic data. However, no specific drillinginformation seems to be available on the rocks along the axis of Flat'Bay anticline. Also, Landsat imagery displays no outcrop in thecenter of the northern dome with definite texture of Precambriancrystalline rocks as is evident in the area of anorthosite at thenortheastern side of the subbasin (Plate I). If exposures of

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Precambrian crystalline rocks are present at the northern dome, theyare poorly exposed and could be covered with glacial drift in mostplaces.

Flat Bay anticline and Anguille anticline, to the south, havebeen interpreted as en echelon folds related to right-lateral wrenchmovement on the Long Range fault. Similarly, the smaller morelocalized anticlines and synclines in the Barachois synclinorium mayalso be en echelon and related to movement on the Long Rangefault. The smaller folds trend N 20° E to N 30° E and are only one ortwo kilometers in length. These folds have been identified in surfacemapping and are not recognizable on Landsat imagery. The axis ofthe Barachois synclinorium parallels the general trend of the enechelon folds. The synclinorium is roughly 32 kilometers long and 14kilometers wide with the axis trending diagonally across thesynclinorium on an average trend of N 25° E. The Barachois Group,consisting of sandstone, siltstone, shale, and coal primarily of MiddlePennsylvanian age, crops out in the central part of the synclinorium.

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STRESSED VEGETATION

Geobotanical anomalies may exist in areas where the soilcontains unusually high concentrations of the certain elements orcompounds. The excess amount of these elements and compoundsmay be harmful to plants growing in the overlying soil causing stress(Lillesand and Kiefer, 1994, p. 180). Thus, the term "stressedvegetation" has been used by geologists when searching for suchanomalies. In some cases plant varieties change in the anomalousareas because some plant types are unaffected by certain seeminglytoxic concentrations. Settle (1984, p. 19-25) discusses the stressedvegetation conditions in a Wyoming oil field, that could be caused bynatural gas seeping from and underlying oil and gas reservoir rock.Ratioing and principal component analysis methods are used toidentify an anomalous area from airborne multispectral imagery.Conclusions from soil tests indicated that anomalously alkaline soilshad restricted the growth of the stunted sagebrush even though therewere enhanced concentrations of hydrocarbon gases in and aroundthe affected area. The extent to which the acidity of the local soilswere modified by the gases was unknown. Conclusions were that thestressed conditions could not be related genetically to the seepage ofhydrocarbons from the underlying reservoir. Although, the tests fromWyoming and another area in West Virginia were not conclusive, itwas concluded that botanical information obtained from remotelysensed imagery may be geologically significant under certaincircumstances.

The Exploration Permit area demonstrated one area, onekilometer square in extent, which may have stressed vegetation. Thisspot is located at the intersection of Crabbes Brook fault withFischells Brook and centered around UTM grid point 382500 m Eastand 5350000 m North. The area is indicated on Figure 5, Plate 1, andthe central brown area on Figure 6.

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Forestry inventory maps for the southwestern part ofNewfoundland, which are four years or more older than the landsatimagery, indicate 31.9 hectares (.319 kilometer-square) of insectinfested forest where Crabbes Brook fault crosses Fischells Brook.This suggests that insects are responsible for the stressedvegetation. Another area, near Flat Bay, Newfoundland but outsidethe study area, displayed a similar anomalous spot of stressedvegetation which corresponded with an insect infested area on theforest-inventory maps. However, all insect infested areas on theinventory maps did not display stressed vegetation on imagery. Thetree types which display stressed vegetation are mostly balsam firand/or black spruce.

The following possibilities seem evident:

1. Stressed vegetation resulted only from insects.

2. Stressed vegetation is due to harmful soil and the forest inventory maps misidentified the area as insect infestation.

3. Stressed vegetation resulted from harmful soil which weakened vegetation so that trees became infested.

4. Neither insects nor soil are responsible for the stressed vegetation on the imagery.

If the soil of the stressed vegetation area tested positive on ahydrocarbon survey then, either 2 or 3 above might be the case.This could lead to the conclusion that hydrocarbons were seeping tothe surface along the Crabbes Brook fault which traverses thestressed vegetation area.

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CONCLUSIONS

Certain structural, stratigraphic, and vegetation characteristicswere evident on the Landsat imagery for Exploration Permit 93-101 inrelation to petroleum evaluation. Conclusions concerning thesecharacteristics are as follows:

1. The Bay St. George subbasin is crossed by eight lineaments with trends ranging from N 900 E to N 65" E, which extend across the basin from the shore of St. George's Bay to the Long Range fault or other east-side bounding faults.

2. If the St. George's Bay fault is present, its extension on land lies immediately east of the Indian Head Range Complex on the north shore of St. George's Bay.

3. The E-W faults of the Cabot Strait identified by earlier marine seismic work, may be related to the eight lineaments which trend across Bay of St. George subbasin. However, no specific conclusions were made concerning the origin of the lineaments.

4. Coves and heads along the southeast shore of St. Ceorge's Bay are related to the places where the lineaments cut across the shore line.

5. The evaporitic strata, consisting of gypsum and rock salt, crop outon the flanks of Flat Bay anticline and can be recognized on Landsatimagery.

6. An area of stressed vegetation, of approximately one square- kilometer, lies over the Crabbes Brook fault near the place where the fault crosses Fischells Brook. Insect infestation may be either a factor or a cause in vegetation stress.

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Respectfully submitted,

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SELECTED BIBLIOGRAPHY

Belt, E.S., 1969, Newfoundland Carboniferous stratigraphy and itsrelation to the Maritimes and Ireland, in North Atlantic geologyand continental drift, a symposium: Am. Assoc. PetroleumGeologists Memoir 12, p. 734-753.

Geological map of Newfoundland, 1955, Map 1043A: GeologicalSurvey of Canada, Ottawa, Canada, scale 1:760,320.

Geological map of Newfoundland, 1967, Map 1231A: GeologicalSurvey of Canada, Ottawa, Canada, scale 1:1,000,000.

Langdon, G.S., and Hall, J., 1994, DL-vonian-Carboniferous tectonicsand basin deformation in the Cabot Strait area, easternCanada: Am. Assoc. Petroleum Geologist Bull., v. 78, no. 11,p. 1748-1774.

Lillesand, T.M., and Kiefer, R.W., 1994, Remote sensing and imageinterpretation, 3rd ed.: John Wiley and Sons, Inc. 750 p.

Knight, Ian, 1983, Geology of the Carboniferous Bay St. Georgesubbasin, Western Newfoundland: Department of Mines andEnergy, Government of Newfoundland and Labrador Memoir 1,358 p.; geologic map, Map 82-1.

Settle, Mark, 1984, The joint NASA/Ceosat test case project,executive summary: Am. Assoc. Petroleum GeologistsBookstore, Tulsa, OK, 30 P.

Webb, G.W., 1969, Paleozoic wrench faults in CanadianAppalachians, in North Atlantic geology and continental drift, asymposium: Am. Assoc. Petroleum Geologists Memoir 12, p.754-786.

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