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Open File: Nfld/2401, compiled by
M.J. Batterson and published March 1994; revised in 2001.
This compilation provides a list of all currently available
surficial and aggregate geology maps for Newfoundland and Labrador.
The maps are listed by NTS map sheet, and are mostly at scales of
1:50,000 or 1:250,000. Maps are available as blue line, printed black
line or colour maps, and digital on demand colour maps. For ease of
searching, information is listed by 1:250,000 scale NTS map sheet,
and is divided into 4 separate categories.
Maps are listed under the headings of Ice Flow, Surficial
Geology and Aggregate Geology. A section of pertinent Current Research
articles is also included because these reports commonly compliment
the associated mapping.
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For information on surficial and aggregate publications, see
Surficial Geology & Aggregate Maps for Newfoundland and
the
Geofiles Database. In the database search Document Type
= All GSNL Maps and Keyword = Surficial
Geology/Geomorphology and title equals either 'ice', 'surficial'
or 'aggregates' to get a list of references.
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These maps provide data used to reconstruct the directions and
sequences of glacial advances during the Quaternary. Most of the data
are from striations, and are presented as directional or
non-directional indicators. A direction is assigned to a striation
where features such as nailheads, miniature rat tails, or outcrop
stossing were identified on a rock surface which unequivocally define
the direction of glacial movement. Where these features were not found
a non-directional orientation is applied. Where more than one set of
striations are found at a site, the relative age can be determined
from either cross-cutting relationships or the preservation of one set
of striae in the lee of a later set. Where a clear age relationship can
be determined a relative age is assigned, with 1 being the oldest.
Where no clear relationship is seen, no relative age is assigned. Some
maps present ice flow data derived from clast fabrics measured from tills.
Clast fabrics describe the orientation and dip of elongate clasts
within a sediment. Elongate clasts will align themselves parallel to
flow lines in a glacier and this orientation may be preserved if the
clasts are deposited beneath the ice. Thus, the orientation of clasts
in sediment (clast fabric) can be used to determine the direction of
ice flow that deposited the sediment. The fabric data shows the last
ice flow to have affected the sediment.
Most maps under the
ice flow heading present only ice flow data. Some maps however, are
surficial geology maps on which ice flow data is recorded.
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Surficial geology maps provide data on the types of material and
landforms found at the surface. These maps are largely derived from
aerial photograph interpretation with a variable amount of field
checking. On some maps a reliability diagram is attached which
outlines the amount of field checking. Each map has a detailed legend
attached that describes the characteristic of each sediment type and
feature encountered. The legend has a genetic category that defines
the sediment type (e.g., glacial, fluvial, aeolian), and a morphology
category that describes the surface expression (e.g., veneer, blanket,
hummocky, fan). Most mapped units contain more than one genetic and/or
morphological type. To accommodate this, units are subdivided by
decreasing dominance (e.g., Tv/Rc means that the area is dominantly a
veneer of glacial sediment, with a lesser area of bedrock concealed by
a mat of vegetation). Up to three genetic or morphological categories
can be accommodated on the maps, with a combination of slashes (/ or
//) and hyphens (-) being used to indicated relative proportions. The
maps provide only a general indication of sediment characteristics and
some variability in sediment is to be expected across a map area. A
till, for instance, may have a silty texture in one part of the area,
and be sandier elsewhere, although both areas will have the T
designation. Similarly, overburden thickness can only be inferred from
these maps.
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These maps provide data on granular or bedrock aggregates within an
area. Granular aggregate maps outline sand and gravel deposits, and
categorise each deposit by their potential as an aggregate producing
area, with Zone 1 having the highest potential. Recent maps commonly
include grain size and petrographic data. Sample data, including grain
size and petrographic analyses, related to other map areas can be
obtained from the Terrain Sciences Section, Geological Survey Branch,
Telephone (709) 729-3888. Potential reserves of material are
approximated based on the aerial extent and depth of natural or
man-made exposures. Detailed descriptions are commonly provided in
associated Current Research articles.
Bedrock aggregate maps
define rock types suitable for construction aggregate uses, including
class A and B material, rip-rap, asphalt and concrete. The suitability
of individual rock types is defined on the basis of physical
characteristics (e.g., hardness, grain size, fractures, mineral
constituents), petrographical properties (e.g., petrographic number)
and chemical/mechanical properties (e.g., abrasion, soundness, alkali
reactivity). Some maps include this data. Data for other areas may be
found in associated Current Research articles or may be obtained from
the Terrain Sciences Section, Geological Survey Branch, Telephone (709)
729-5634.
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