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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>Geologic Map of New Mexico. This feature class represents contacts between geologic units which may be either lithostratigraphic (stratiform) and lithodemic (do not conform to law of superposition) within the Geologic Map of New Mexico. ContactsAndFaults and MapUnitLines are used to build polygons (MapUnitPolys) and are topologically related to these polygons. These feature classes also represents mapped faults, joints, sheer zones, key beds, and thin map units (measured fault orientations are stored in OrientationPoints) related to contacts between geologic units. Fault data such as measurements of fault planes and slickenlines are recorded as point data in OrientationPoints which, for mapped faults, lie along these lines.</SPAN></P><P><SPAN>Map boundaries, open water boundaries, and snowfield and glacier boundaries delineate the edge of certain map unit polygons and in this sense are contacts. Therefore, they are included in this feature class. Map-unit-bounding fault lines are legitimate elements of this feature class and should not be coincident with contacts.</SPAN></P><P><SPAN>Lines symbolized as “contact”, “contact inferred” and “contact approximately located” are Type = “contact”, but have differing LocationConfidenceMeters, ExistenceConfidence, and (or) IdentityConfidence. Their symbolization may change with map scale.</SPAN></P><P><SPAN>We recommend using “blank” as the value of Symbol for scratch boundaries (where no line is drawn between adjoining polygons, also known as wash boundaries); scratch boundaries are occasionally used for contacts with exceptionally large values of LocationConfidenceMeters.</SPAN></P><P><SPAN>Example values for the Type field can include:</SPAN></P><UL><LI><P><SPAN><SPAN>contact</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>internal contact</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>gradational contact</SPAN></SPAN></P></LI><LI><P><SPAN>fault</SPAN></P></LI><LI><P><SPAN>normal fault</SPAN></P></LI><LI><P><SPAN>reverse fault</SPAN></P></LI><LI><P><SPAN>thrust fault</SPAN></P></LI><LI><P><SPAN>map boundary</SPAN></P></LI><LI><P><SPAN>key bed</SPAN></P></LI></UL><P><SPAN>Symbolization should follow the FGDC Digital Cartographic Standard for Geologic Map Symbolization (FGDC-STD-013-2006) with few exceptions. If the FGDC Standard does not define a suitable symbol required for a geologic map, the standard may be supplemented with custom symbols or a repurposed symbol may be used with the existing FGDC symbols that are “repurposed” for alternate use in the map. Such repurposed symbols should be identified in the RepurposedSymbols data table, which becomes a required table if FGDC symbols are repurposed.These data are coded using a "zero" padded code (01.01.01 vs 1.1.1) using the USGS published FGDC Digital Cartographic Standard for Geologic Map Symbolization.</SPAN></P><P><SPAN>The New Mexico Bureau of Geology and Mineral Resources have configured a data table that contains the definitions and symbol codes to readily reference the symbology used in the feature classes. This data table is named FGDC_Symbols. This will be the primary table used to generate the "Explanation of Map Symbols" in a map layout. When used in conjunction with the RepurposedSymbols data table, the FGDC_Symbols will record any deviations from the FGDC Standard.</SPAN></P><P><SPAN>This list is derived from the FGDC standard, sections 1, 2, 30, and 31. Other values certainly are possible. In all cases, note that modifiers such as “approximate”, “certain”, “concealed”, and “queried” are not encoded in Type. These modifiers reflect the convolution of LocationConfidenceMeters, ExistenceConfidence, IdentifyConfidence, and the map scale. The description of a contact as “approximate” is not literally preserved in a GeMS database; this information is preserved with the appropriate value of LocationConfidenceMeters. When migrating an existing map into the GeMS schema it is often convenient to store “contact, approximate” in a temporary field (e.g., LTYPE) that is later parsed to calculate values of Type, LocationConfidenceMeters, etc.</SPAN></P><P><SPAN>COMMENTS TO MAP USERS</SPAN></P><P><SPAN>A geologic map displays information on the distribution, nature, orientation, and age relationships of rock and deposits and the occurrence of structural features. Geologic and fault contacts are irregular surfaces that form boundaries between different types or ages of units. Data depicted on this geologic quadrangle map may be based on any of the following: reconnaissance field geologic mapping, a compilation of published and unpublished work, and photogeologic interpretation. Locations of contacts are not surveyed but are plotted by interpretation of the position of a given contact onto a topographic base map; therefore, the accuracy of contact locations depends on the scale of mapping and the interpretation of the geologist(s). Any enlargement of this map could cause misunderstanding in the detail of mapping and may result in erroneous interpretations. Site-specific conditions should be verified by detailed surface mapping or subsurface exploration. Topographic and cultural changes may not be shown due to recent development. Cross sections are constructed based upon the interpretations of the author made from geologic mapping and available geophysical and subsurface (drill hole) data.</SPAN></P><P STYLE="margin:0 0 11 0;"><SPAN>Cross sections should be used as an aid to understanding the general geologic framework of the map area and not be the sole source of information for use in locating or designing wells, buildings, roads, or other human-made structures.</SPAN></P><P STYLE="margin:0 0 11 0;"><SPAN>The New Mexico Bureau of Geology and Mineral Resources created the Open-File Geologic Map Series to expedite the dissemination of these geologic maps and map data to the public as rapidly as possible while allowing for map revision as geologists continued to work in map areas. Each map sheet carries the original date of publication below the map and the latest revision date in the upper right corner. In most cases, the original publication date coincides with the date of delivery of the map product to the National Cooperative Geologic Mapping Program (NCGMP) as part of New Mexico’s STATEMAP agreement. While maps are produced, maintained, and updated in an ArcGIS geodatabase, at the time of the STATEMAP deliverable, each map goes through cartographic production and internal review before uploading to the Internet. Even if additional updates are carried out on the ArcGIS map data files, citations to these maps should reflect this original publication date and the original authors listed. The views and conclusions contained in these map documents are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the State of New Mexico or the U.S. Government.</SPAN></P></DIV></DIV></DIV> |
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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN STYLE="font-size:12pt">Any use of this geologic map, directly or indirectly via derivative products, must include a citation to the Authors, the Publisher (The New Mexico Bureau of Geology and Mineral Resources), the published year, the map series and number, and any contributing agencies like the USGS with regard to maps that were partially funded under the STATEMAP program.</SPAN></P></DIV></DIV></DIV> |