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Karst Potential Classification
The karst potential map shows the tendency for geologic units to develop or have karst features such as sinkholes, springs, caves, or other solution features. The classification is based on lithology. The lithologic characteristics used are percentage of CaCO3 in the carbonate portion of the unit, grain size, bedding thickness, and insoluble components. Insoluble components may occur as a mineral grains within the limestone lithology or as interbeds of noncarbonate rock. These criteria were evaluated for all rock units and combined rock units that appear on the map, and resulted in about 50 distinct rankings. These rankings were reduced to three to five simplified classes by analysis of their frequency of distribution and the scale of the map data.
1:500,000 (small scale) map data (viewed at scales 1:150,001 and smaller) displays three classes:
 
INTENSE
Areas underlain by bedrock with high potential for karst development. May exhibit mature karst, including caves, sinkholes, and springs where they crop out.
 
PRONE
Areas underlain by bedrock with moderate potential for karst development. Development of karst features in this category is variable and dependent on site-specific conditions. Occurrence of caves may be influenced by physiographic setting, unit thickness, and lithology.
 
NONKARST
Areas underlain by bedrock with limited or no potential for karst development. Karst features rare or absent.

1:24,000 (large scale) map data (viewed at scales 1:150,000 and greater) displays five classes:
 
VERY HIGH
Thick-bedded, typically fine-grained and pure limestone units with little or no insoluble content. Will exhibit mature karst, including caves, sinkholes, and springs where they crop out.
 
HIGH
Limestone units with low insoluble content, but varied grain size and bedding characteristics. Likely to contain karst features. Occurrence of caves may be influenced by physiographic setting, unit thickness, and lithology.
 
MEDIUM
Limestone units and coarse-grained, or siliciclastic units with limestone interbeds. Limestone units may contain a high percentage of insoluble minerals. Siliciclastic units will only be karst-prone where limestone beds occur in the near surface. Development of karst features in this category is variable and dependent on site-specific conditions.
 
LOW
Siliciclastic units with minor limestone beds or units primarily composed of dolomite. Karst features are poorly developed or absent.
 
NONKARST
Consolidated or unconsolidated siliciclastic units. Karst features rare or absent.

Two different sinkholes layers are displayed in this layout:
Statewide Sinkhole Outlines
These data represent digital GIS sinkhole coverage for all of Kentucky. The highest elevation, closed, topographic contour of each mapped sinkhole was digitized as a GIS polygon. The second highest elevation contour was also digitized where very large, shallow, karst valleys were so expansive that the area covered by the polygon obscured patterns in sinkhole distribution. These karst valleys are mostly confined to the Western Pennyroyal. The spacing of contour intervals on the topographic maps of the state vary in from 40 foot to 10 foot. No attempt was made to use a constant elevation, standardize the outline to a uniform contour interval, or record the elevation of the digitized contour. Digitization was done onscreen using digital raster graphic files of the 7.5-minute topographic contours, registered and projected to the Kentucky State Plane coordinate system.
LiDAR-derived Sinkhole Outlines
The sinkhole maps are derived from LiDAR data using ArcGIS 10.1. LiDAR data were used to create digital elevation model (DEMs). Surface depressions were then extracted from the DEMs and visually inspected for sinkholes. Field verification suggests that the accuracy of the identified sinkholes to be real sinkholes is over 85%. The data provided here are provisional and updates will be provided if needed. LiDAR data were provided by the Louisville/Jefferson County Information Consortium (LOJIC) through Kentucky Division of Geographic Information. The LiDAR was flown in August, 2009 and the average point spacing is 1.0 meter. DEMs were created using LAS Class 2 surface with 5 feet resolution. Each sinkhole is presented as a polygon feature and the attribute table contains the following fields:
SinkholeID: an 8-digit numerical code, in which the left three digits represent FIPS county code and the remaining five digits are sequential.
Latitude: latitude of the centroid of the sinkhole
Longitude: longitude of the centroid of the sinkhole
Area_sqft: the approximate surficial area of the sinkhole
County: County location of the sinkhole
Method: the method used for identifying the sinkhole
Field Verified: Show if the sinkhole is checked and verified in the field.
 

Geologic Map Service Tutorials:


Overview of Map Functionality
Most of the map functionality is provided in the tabs on the right-side of the map interface:

Tools. The tool tab contains standard tools for zoom and pan control of the map. In addition there are several custom tools:

Query. This functionality allows you to search the Kentucky Geological Survey database for geologic descriptions from KGS publications, maps, and field notes and highlight those units on the map. Follow the instructions on the tab for more information about using this feature.

Legend. This tab provides explanations of symbology for the map layout. The map unit colors display the map colors for the units in the viewed extent. Other map symbols are displayed below the colors and are also displayed with each map layer on the "Layers" tab.

Layers. This tab provides controls for changing the layout of the map. There are three main sections in this tab: Geologic Information. There are two ways to get information about geologic units or other features on the map. The identity tool , described above, is used to gather information about specific features. It works by clicking on the map and the results are sent to a pop-up window. The identity tool only returns descriptions from the 1:24,000-scale GQ's. Be aware that the sensitivity of the tool is scale-dependant. Clicking at small scales may return descriptions for multiple map units or features.

The Geologic Information tab provides comprehensive searches for all information that pertains to the map extent. Because of the larger amount of information that is accessed, the searches are provided from individual links. The results are grouped by type of source and then by the individual source title. The source title is a link to the KGS online list of publications, where many publications can be viewed. For lithology descriptions, a portion of the graphic stratigraphic column is provided for context, and the full stratigraphic column is accessed from a link.