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Regional Surficial Geology Help File |
CONTENTS
IntroductionMethod
Aerial Photograph Interpretation
Transferring Interpretation
Into the GIS
Surficial Geology
Map Legend
Table 1 Variables included in the Surficial Geology database
Table 2 Genetic1Ma values assigned to the Genetic250 values
Symbology File
Disclaimer
Recommended Citation
References
Contact
INTRODUCTION
This help file contains documentation for the regional surficial geology of Newfoundland and Labrador. The surficial geology map layer provides data on the types of material and landforms found at the surface of the earth. It was derived from 1:50 000, 1:250 000 and 1:1 000 000 scale surficial geology maps, aerial photograph interpretation and variable amounts of field verification.
The regional surfical geology map of the Island of Newfoundland was compiled by Liverman and Taylor (1990a). The compiled paper version was prepared at a scale of 1:500 000 (Liverman and Taylor, 1990b). The regional surficial geology map of Labrador was compiled by Klassen et al. (1992, Map No. 1814A) at a 1:1 000 000 scale.
The map presented in the Geoscience Atlas, is based on the attributes in the 'Genetic1Ma' field (see Table 1). These are attributes as defined in Klassen et al. (1992) for the Labrador map. The surficial geology attributes in the 'Genetic250' field, for the Island portion of the map, were translated to the equivalent attribute in the 'Genetic1Ma' field (see Table 2).
METHOD
Aerial Photograph Interpretation
1:50,000 scale black and white photos were interpreted, followed by ground verification in the field. The legend combines major landform types (fluvial, glaciofluvial, marine, till etc.) with morphology (eroded, lineated, blanket etc.). The proportion of landscape types are shown by slashes and dashes (e.g. Tv/Tr).
Transferring Interpretation
Aerial photograph interpretation was transferred to a sepia base. Polygon boundaries and labels were checked and revised as necessary. The final version was then transferred to a blank mylar sheet registered to a topographic basemap.
Into the GIS
The line work (including polygon labels) was scanned and then digitized.
Labels were checked for accuracy, any polygon labeling conflicts were identified,
and problems resolved, commonly by further aerial photograph interpretation.
SURFICIAL GEOLOGY
The surficial geology of Newfoundland and Labrador is subdivided into 5 main categories: bedrock, till, glaciofluvial, raised marine and modern sediments/Holocene sediments (including fluvial sand, gravel and silt (alluvium) found adjacent to modern streams, colluvium at the base of steep hills, modern marine deposits such as beaches and tidal flats, and Aeolian deposits). This database includes the surficial geology at a 1:1 000 000 scale for Labrador and 1:250 000 scale for the island of Newfoundland. The attributes in the database are presented in Table 1.
MAP LEGEND
for both the Genetic250 and Genetic1Ma fields (from Klassen et al., 1992 and Liverman and Taylor, 1990a and 1990b)
Ablation Drift: sediments and landforms formed during the disintegration of the ice sheets; predominantly massive to poorly stratified, silty to sandy diamicton and poorly sorted to well sorted sand and gravel; characterized by irregular hummocks and mounds 5 to 10 m high and by extensive meltwater channels; on northern Labrador Peninsula, can include glaciolacustrine and glaciomarine deposits.
Alluvium (fluvial): moderate to well sorted gravel, sand, silt and clay deposited in modern river systems.
Bog: accumulation of degraded organic matter deposited in poorly drained low lying areas.
Colluvium: accumulation of poorly sorted detritus around the base of steep hills derived from the slopes above.
Concealed bedrock: mainly bedrock concealed by vegetation with patches of till, sand and gravel and bog and exposed rock.
Drift Poor areas: greater then 80% bedrock; includes areas of till and other surficial materials generally less than 1m thick and discontinuous; on northern Labrador Peninsula, characterized by extensive boulder fields, dominantly felsenmeer.
Exposed bedrock: areas of bedrock with little or no surface sediment (or vegetation cover).
Glaciofluvial deposits: proglacial or ice contact sand and gravel; forming ice contact fans and deltas, outwash plains and terraces, potted outwash, crevasse fillings, kame terraces, commonly associated with askers; includes areas of extensive, thick fluvial sediments derived from pre-existing glaciofluvial deposits.
Glaciofluvial Gravel and Sand: variable thicknesses of gravel and sand with diverse topographical expressions. It consists mainly of poorly to moderately sorted gravel with 5-50% sand.
Glaciolacustrine Deposits: sandy, poorly sorted sediments deposited within lakes dammed by glacier ice; forming blanket deposits > 2m thick.
Glaciomarine and Marine Deposits: gravel, sand and mud deposited or modified within a glaciomarine or marine environment, undifferentiated; forming extensive, thick (>5m) blanket accumulations; includes ice contact deposits.
Hummocky Terrain: a blanket of till having an irregular hummocky topography and relief of 2 to 10m. Hummocks mostly till, but may contain sand and gravel.
Marine clay, sand, gravel and diamicton: varies in composition and recognized by its topographic position relative to the modern sea level, and geomorphology. Incorporates: planar terraces of sand and gravel, silt and clay plains, diamicton blanket, sand and gravel ridges and sand and gravel at or near Modern Sea Level.
Ridge Till: a blanket of till having topography consisting of ridges oriented parallel or perpendicular to ice flow.
Rogen Moraine: irregular to sinuous ridges which are generally less than 1km long and 10 m high, or hummocks; composed of massive to poorly stratified, sandy diamicton, gravel and sandy gravel; can be mantle by large boulders. Ridges trend roughly perpendicular to ice flow; fields of ribbed moraine vary in outline form irregular and blocky to elongate, lying parallel to regional ice movement; in the south ribbed moraine preferentially occurs within valleys.
Till blanket: continuous till cover thicker than 1.5m. Includes areas of eroded till.
Till, undifferentiated: predominantly nonstratified, poorly sorted, silty to sandy diamicton, gravel and sandy gravel; deposited either directly from ice or by meltout during ablation; includes glaciofluvial, glaciolacustrine, marine, and fluvial deposits of either minor area/extend or thin (<2m) and discontinuous.
Till veneer: thin (1.5 m) discontinuous sheet of till overlying bedrock. Patches of exposed bedrock and thicker sediment common. Relief and topography variable.
| SURFICIAL GEOLOGY ATTRIBUTES | |
|---|---|
| VARIABLE | DESCRIPTION |
| Genetic250 | Description of surficial geology units at 1:250 000 scale for Labrador |
| Genetic1Ma | Description of surficial geology units at 1Ma scale for Newfoundland and Labrador |
| Source | Organization (GSNL or GSC) |
| Reference | Sources from which sample information was obtained |
| Red | Amount of red (0 to 255) in the polygon colour |
| Green | Amount ofgreen (0 to 255) in the polygon colour |
| Blue | Amount ofblue (0 to 255) in the polygon colour |
in the surficial geology polygons on the Island of Newfoundland.
| SURFICIAL GEOLOGY EQUIVALENT VALUES | |
|---|---|
| Genetic250 | Genetic1Ma |
| alluvium | alluvium |
| bog | bog |
| colluvium | colluvium |
| concealed bedrock | drift poor |
| exposed bedrock | exposed bedrock |
| glaciofluvial gravel and sand | glaciofluvial |
| hummocky terrain | ablation drift |
| marine clay, sand, gravel and diamicton | glaciomarine and marine |
| ridge till | rogen moraine |
| till blanket | till blanket |
| till veneer | till, undifferentiated |
To Top
SYMBOLOGY FILE:
For ArcGIS users, to symbolize the regional surficial geology polygons please download this layer file.
DISCLAIMER
Open File reports, maps and digital data issued by the Geological Survey Division of the Mining and Mineral Development Branch, Government of Newfoundland and Labrador, are made available for public use. They have not been formally edited or peer reviewed, and are based upon preliminary data and evaluation. The user agrees not to provide a digital reproduction or copy of this product to a third party. Derivative products should acknowledge the source of the data.
The Geological Survey (the "authors and publishers") retains the sole right to the original data and information found in any product produced. The authors and publishers assume no legal liability or responsibility for any alterations, changes or misrepresentations made by third parties with respect to these products or the original data. Furthermore, the Geological Survey assumes no liability with respect to digital reproductions or copies of original products or for derivative products made by third parties. Please consult with the Geological Survey in order to ensure originality and correctness of data and/or products.
RECOMMENDED CITATION
(for downloaded database)
Newfoundland and Labrador Geological Survey. "Surficial Geology - Regional." Newfoundland and Labrador GeoScience Atlas OnLine. Last update: 2011. https://geoatlas.gov.nl.ca . [fill in date downloaded].
The original source should be referenced wherever possible. Please refer to the Index of Surficial Geology and Aggregate Maps (link below) or the Geofiles, to search for the pertinent reports and maps.
REFERENCES/SOURCES
View the individual Surficial Geology Maps through the Geoscience Atlas in the Indexes Group - Index of Surficial Geology Maps layer (link to the individual maps)or view all the maps through the Surficial Geology Group - Regional Surficial Geology layer.
Klassen, R. A., Paradis, S, Bolduc, A. M and Thomas, R. D
1992. Glacial landforms and deposits, Labrador, Newfoundland and eastern Quebec. Geological Survey of Canada, 'A' Series
Map n. 1814A.
Liverman, D. and Taylor, D.
1990a. Surficial geology map of insular Newfoundland. In Current research, Edited by C. P. G. Pereira,
D. G. Walsh and R. F. Blackwood, Government of Newfoundland and Labrador, Department of Mines and Energy,
Geological Survey Branch, Report 90-01, 1990, pages 39-48.(
pdf - 2.68mb)
Liverman, D. and Taylor, D.
1990b. Surficial geology map of insular Newfoundland, preliminary version.
Government of Newfoundland and Labrador, Department of Mines and Energy,
Geological Survey Branch, Map 90-008, Open File NFLD/1994, scale 1:500 000.
CONTACT
Dave Taylor
Project
Geologist
Geochemistry, Geophysics and Terrain Sciences Section
Geological Survey Division, Mining and Mineral Development Branch
Government of Newfoundland and Labrador
P.O. Box 8700,
St. John's, NL A1B 4J6
t. (709) 729-5624
Email: davetaylor@gov.nl.ca
General Email: GeoscienceOnline@gov.nl.ca
(Help File updated: October 2022)
(Database last updated: check the What's New file)