SURFICIAL GEOLOGY – SCARPS AND DRUMLINS

Field	Description
Main ID Information	Metadata Updated 2007
Title	Benton County Aggregate Evaluation – Scarps and Drumlins (lines)
Filename	Sgeoxln3 (ArcView Shapefile)
Abstract	This dataset consists of information about the types of landforms and features that are represented by an line (arc). These landforms consist of channel scarps and drumlins.
Place Keywords	Benton County, Minnesota
Theme Keywords	Landforms, Features
Time Period of Content	Fall 2001 – Spring 2002
Parent Theme	NA (Agp02py3)
Spatial Extent of the Data	Benton County, Minnesota
Contact Person	Aggregate Resources Mapping Program
Contact Person Organization/Division	Department of Natural Resources, Division of Lands and Minerals
Contact Person Position	Geologist or GIS Specialist
Contact Address	500 Lafayette Road, Box 45
Contact City	St. Paul
Contact Zip Code	55155-4045
Contact Voice Phone	651-259-5959
Contact Fax Phone	651-296-5939
Additional ID Information
Originator	Department of Natural Resources, Division of Lands and Minerals, Mineral Potential Section
Purpose	To display linear surficial geologic landforms and features that were too small to be mapped as polygons.
Progress	Complete
Currentness Reference	All data was gathered in the late fall of 2000 and the summer and fall of 2001 and compiled in the Fall of 2001 through the spring of 2002.
Maintenance Frequency	None planned
Access Constraints	NA
Use Constraints	NA
Associated Data Sets	Aggregate Potential and Surficial Geology (Agp02py3 and Agp02ln3).
Data Quality
Attribute Accuracy	These lines were digitized on screen with DOQs and DRGs (topographic maps) as the backdrops.
Logical Consistency	NA
Completeness	The units were delineated by aerial photograph interpretation (1:40,000), and digitized on screen using ARCVIEW; with DOQ’s and DRG’s (topographic maps) as the backdrops.
Horizontal Positional Accuracy	1:50000
Vertical Positional Accuracy	NA
Lineage	Color infrared and black-and-white aerial photographs were used to delineate geological landforms and aggregate resources. Stereoscopic pairs of color infrared aerial photographs (NAPP, 9"x9" at 1:40,000 scale, April 1991 and 1992) were used along with reconnaissance-level, high-altitude, black-and-white photographs (1:80,000 scale). Aerial photographs (DOQs) were also available digitally and used within ARCVIEW (1:12,000 scale). Aerial photographic interpretation was completed with a glacial mapping technique known as the landsystems approach. This technique relies on the principle that depositional glacial landforms are composed of a predictable range of sediments, some consisting of sorted sand and gravel and others consisting of silts, clays, or unsorted materials. In addition to the landsystems approach, several other general characteristics helped determine the nature of the material, such as tonal contrasts, texture, context, shape, size, trend, association, and patterns. These characteristics can help determine the properties of the surface material (e.g., certain vegetation grows on well drained soils such as sand and gravel, which on an aerial photograph has a distinctive texture, tone, pattern, etc.). The landform recognition approach (part of the landsystems approach) was also used when interpreting the topography within Benton County; glacial landforms have distinct and unique shapes and patterns that can be observed in their topographic expression. Topographic maps (USGS 1:24,000), digital elevation models, and shaded relief maps were all used to help delineate these sand and gravel bearing features. The topographic expression of a feature can also be observed by looking at the distribution of lakes and wetlands. For example, a string of lakes and/or wetlands may be the signature of a glacial outwash channel or collapsed channel, which may host sand or gravel deposits. Several aggregate bearing features were located using this technique (outwash channels, collapsed channels, glaciofluvial fans, eskers, and terraces).
Source Scale Denominator	1:50000
Spatial Reference
Horizontal Coordinate Scheme	UTM
Ellipsoid	GRS80
Horizontal Datum	NAD83
Horizontal Units	Meters
Distance Resolution	NA
Altitude Datum	NA
Altitude Units	NA
Depth Datum	NA
Depth Units	NA
UTM Zone Number	15
Raster only
Cell Width	NA
Cell Height	NA
Spatial Data Organization
Geographic Reference for Tabular Data	The lines represent geologic landforms that are too small to be mapped as polygons.
Native Dataset Environment	ArcView 3.1 / ArcInfo 8.0.2
Vendor Specific Object Type	NA
Tiling Scheme	NA
Spatial Object Type	Vector
Transfer Size	378 kb
Entities -- Attributes
Entity-Attribute Overview	The lines represent geologic landforms that are too small to be mapped as polygons.
Entity-Attribute Detailed Citation	ArcView specific fields include shape (i.e., feature type - polyline), fnode_ (id of beginning node of line), tnode_ (id of ending node of line), lpoly_ (id of polygon to the left of the line - “0" if a line feature, not a line defining a polygon), rpoly_ (id of polygon to the right of the line - “0" if a line feature, not a line defining a polygon), Length (length of line segment), sgeoxln3_ (unique id for line, assigned by Arc/INFOsoftware), sgeoxln3_i (an id usually assigned during theme creation). The scarp and drumlin line attributes are described in the table below.

Table Name	Field Name	Begin Column	Definition	Valid Values	Descriptions
Sgeoxln3.shp	Uniqln_id		Number,3,0	263	Drumlin (Length)
				264	Drumlin (Width)
				265	Channel Scarp - well defined
				266	Channel Scarp - inferred
	Sgeolntype		Text, 33	Channel Scarp (Well Defined)	Channel Scarp - well defined
				Channel Scarp (Inferred)	Channel Scarp - inferred
				Drumlin (Length)	Elongated ridge of till – oriented in the direction of ice flow. Defines the length of a drumlin.
				Drumlin (Width)	Elongated ridge of till – oriented perpendicular to the direction of ice flow. Defines the width of the drumlin.