Codes for the identification of aquifer names and geologic units in the United States and the Caribbean outlying areas

U.S. GEOLOGICAL SURVEY CIRCULAR 878-C U.S. GEOLOGICAL SURVEY CIRCULAR 878-C

Dallas L. Peck, Director

1. Purpose and Scope................................................ C2
2. Specifications for the codes..................................... C2
3. Availability of the codes........................................ C8

2.1 Purpose and source of the codes............................. C2 2.2 Description of the codes.................................... C2 2.3 Development of the codes.................................... C2 2.3-1 Development of the first part of the code................. C2 2.3.2 Development of the second part of the code................ C2 2.3.3 Development of the third part of the code................. C6 2.4 Examples of the codes....................................... C6 2.5 Qualifications of the codes................................. C6

2. Order of letter elimination.................................. C5 Page

III This standard provides codes to be used for the identification of aquifer names and geologic units in the United States, the Caribbean and other outlying areas. Outlying areas include Puerto Rico, the Virgin Islands, American Samoa, the Midway Islands, Trust Territories of the Pacific Islands, and miscellaneous Pacific Islands. Each code identifies an aquifer or rock-stratigraphic unit and its age designation. The codes provide a standardized base for use by organizations in the storage, retrieval, and exchange of ground-water data; the indexing and inventory of ground-water data and information; the cataloging of ground-water data aquisition activities; and a variety of other applications.

Acknowledgment is given to the following personnel of the U.S. Geological Survey who served on a technical working group which had the responsibility for the technical review and validation of this standard: Abstract

Claire B. Davidson, Water Resources Division Robert L. Laney, Water Resources Division Gwendolyn W. Luttrell, Geologic Division David V. Maddy, Water Resources Division Charles 0. Morgan, Water Resources Division Owen 0. Williams, Water Resources Division This standard provides codes used for the identification of aquifer names and geologic units in the United States, the Caribbean and other outlying areas. Outlying areas include Puerto Rico, the Virgin Islands, American Samoa, the Midway Islands, Trust Territories of the Pacific Islands, and miscellaneous Pacific Islands. Each code identifies an aquifer or rock-stratigraphic unit and its age designation. The codes provide a standardized base for use by organizations in the storage, retrieval and exchange of ground-water data; the indexing and inventory of ground-water data and information; the cataloging of ground-water data acquisition activities; and a variety of other applications.

The codes apply to all areas of the United States and the Caribbean outlying areas including Puerto Rico and the Virgin Islands. Codes have also been developed for use in American Samoa, the Midway Islands, Trust Territories of the Pacific Islands, and miscellaneous Pacific Islands.

in the U.S. Geological Survey's National Water Data and Storage System (WATSTORE) that was established in 1971. The coding procedures are based on the rock-stratigraphic coding system proposed by the American Association of Petroleum Geologists and published in its October 1967 bulletin. The code identifies the aquifer or rock-stratigraphic unit and its age designation.

eight characters in length, and consist of three parts. The first part contains three numeric characters that identify the erathem, system, and series (time-stratigraphic units) of the rock unit. The second part contains up to four alphabetic characters for the name of the rock-stratigraphic unit. A mnemonic code is developed by the selection of letters from the name. Rules for this procedure are given below. The third part of the code is a single character in position eight and denotes a qualifying term for parts of the rock unit such as upper, middle, lower, or basal part. The third part may not always exist.

to be used in the development of the codes.

numeric codes that may be used for the first part. If a rock unit extends across more than one time-stratigraphic unit, the numeric code for the youngest unit is selected.

the second part of the code are: 2.1 Purpose and Source of the Codes. The codes were developed for use

2.2 Description of the Codes. The codes are alphanumeric, a maximum

2.3 Development of the Codes. The following sections describe the rules

2.3.1 Development of the First Part of the Code. Table 1 lists the

2.3*2 Development of the Second Part of the Code. The rules used for

(1) The second part of the code is developed by eliminating letters from the orginal name until no more than four letters remain. Prior to eliminating letters, the following should be dropped from the rock-stratigraphic name.

Cenozoic....................... 100 Quaternary................... 110 Holocene................... 111 Pleistocene................ 112 Tertiary....................... 120 Pliocene.....................121 Miocene...................... 122 Oligocene.................... 123 Eocene....................... 124 Paleocene.................... 125

Jurassic.....................220 Upper......................221 Middle.....................22*1 Lower...................... 227 Triassic.....................230 Upper......................231 Middle.....................234 Lower......................237

Paleozoic...................... 300 Permian...................... 310 Upper......................311

Devonian......................... 340 Upper..........................341 Middle.........................344 Lower.......................... 347 Silurian.........................350 Upper..........................351

Ordovician....................... 360 Upper.......................... 361

Precambrian (informal time term).400 Proterozoic (formal time term)...401 Late...........................410 Middle......................... 420 Early..........................430 Archean (formal time term).......404 Late...........................440 Middle.........................450 Early..........................460 Pre-Archean (informal time term).407 Code

St. Croixan..................372 considered as two words. Abbreviations, such as "St. 11 , are to be retained and not written out.

infrequent case of aquifers or other rock units named by their depth of occurrence at some geographic locality, such as the "500-foot sand of the Memphis area."

500-foot of the Memphis area 05MP 2000-foot sand of the Baton Rouge area 20BR (2) Rock names such as McGregor, St. Lawrence, Van Alien are to be

(3) Replace all non-alphabetic characters with blanks, except in the

(4) Deletion of letters and double letter elimination proceed in the

(5) Deletion is continued until the mnemonic is reduced to at least

(6) In the rare instances where the mnemonic reduces to a first letter

(7) If the original word is smaller than four characters and the depth A. The rank off the unit; such as group, formation, member. B. Any lithologic descriptors; such as, sandstone, shale, or limestone. C. Insignificant words; such as, the, on, a, an. D. Qualifying terms such as upper, middle, or lower. These terms are used in the development of the third part of the code (see below).

A. If no depth of occurrence is indicated, a mnemonic code of up to four alphabetic characters is generated from the name to form the second part of the data code.

B. If depth of occurrence is included with the name, the first two characters of the second part are numeric and represent the depth, while a two-character mnemonic is generated from the alphabetic portion of the name to form the last two characters of the second part. To obtain the numeric representation, form the depth value into a four-digit numeric by adding leading zeros if necessary, and then select the two leftmost digits. For example:

sequence of steps given in table 2. For double letter elimination (step 9 of table 2), one letter of each double letter is deleted. For elimination of each individual letter (other steps of table 2), deletion proceeds from right to left; each occurrence is deleted except for the first letter of a word.

four characters, or two characters if the depth of occurrence is included.

and two sets of double letters (as FTTRR) eliminate the first letter on the right without regard for the letter sequence shown in table 2.

of occurrence is not indicated, the word is entered in the data field left justified. Do not add any characters to fill up the data field. Leave unused spaces blank. C4

9. Double Letters 18. F 27. Z (delete one)

code may be used for modifiers and qualifying terms of the rock-stratigraphic unit. If the word to be coded in position eight is upper, middle, or lower, use the letters U, M, or L, respectively, for the code. If any other word is to be coded in position eight and the first letter is U. M, or L, use the last letter that remains after following the elimination procedure of table 2, other than U, M, or L.

assigned codes for aquifer names or rock stratigraphic units within one State.

this standard may be made by U.S. Geological Survey employees and must be forwarded to the Assistant Chief Hydrologist for Scientific Information Management, Water Resources Division, U.S. Geological Survey, 440 National Center, Reston, Virginia 22092, who will verify the acceptability of requests with the Water Resources Division's representative on the Geologic Names Committee. A copy of each request should also be forwarded to the Chairman, Data Standards Committee, U.S. Geological Survey, 115 National Center, Reston, Virginia 22092. When requesting new codes, the following information must be provided:

When requesting changes to existing codes, the following information must be provided:

(8) If duplicate codes appear, some alteration of the code will be made

2.3*3 Development of the Third Part of the Code. Position eight of the

2.4 Examples of the Codes. Figure 1 contains a sample list from the

2.5 Qualifications of the Codes. Requests for changes or additions to

1. States(s) in which the name of the unit is to be used.
2. Name of the unit for which a code is being requested. If the unit is a member of a formation, include the formation name also.
3. Geologic age of the unit; if more than one age is represented, provide a Isit of all ages involved.
4. The listing of the code and aquifer name exactly as it appears in the standard's list of codes and names.
5. The corrections) to be made.
6. The reason for the change and verification that the requested change is acceptable to any other States that may be affected.

by the U.S. Geological Survey. This must be done to insure system-wide uniqueness. The rule to be followed with formal names will be to retain the correct mnemonic code with the name which has priority in time. The second name will be coded retaining the first vowel. If more than two names reduce to the same mnemonic, it may be necessary to make some arbitrary code adjustment for the third and any subsequent names. These same rules will be used, where possible with informal names.

C6 Figure 1. Example of aquifer names and geologic unit codes

3. Availability of the Codes

The list of codes for the identification of aquifer names and geologic units is dynamic in that codes are frequently added or changed as new information becomes available. A current list of codes assigned to the standard may be obtained by written request to the National Water Data Exchange, U.S. Geological Survey, M21 National Center, Reston, Virginia 22092.

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