Map Unit Abbreviations for Stratigraphic Age Trish Ekberg Montana Bureau of Mines and Geology (MBMG) November 8th, 2021 How the question came up .. a conversion project Guidance from GeMS about MapUnit field: p. 12 p. 15 p. 17 p. 19 What
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Presentation Transcript
01
Map Unit Abbreviations for Stratigraphic Age Trish Ekberg
Montana Bureau of Mines and Geology (MBMG)
November 8th, 2021<br>
02
How the question came up ….. a conversion project<br>
03
Guidance from GeMS about MapUnit field: p. 12 p. 15 p. 17 p. 19<br>
04
What to do? Option 1 – just use the special characters
technically * _ } etc are ASCII (shift-key accessible)
not very easily understood
not traditional use
Option 2 – let authors pick for each map/project
Age abbreviations are explained in DMU table
Might result in adjacent maps not using the same map unit abbreviation for the same unit
(okay according to USGS suggestions to Authors)
https://pubs.usgs.gov/unnumbered/7000088/sta08.pdf p. 11<br>
05
What to do? Option 3 – Not use age identifiers
Only represent lithology in the MapUnit field
Could also be done with formal names
Common with man-made materials
Keeps age information only in Age (DMU table) and Label field (DMU and MapUnitPolys table)
Not in line with USGS Suggestions to Authors
Not traditional use? pc Tertiary Pine Creek sandstone<br>
06
Option 4 – standardize age abbreviations
…….not so easy…
All Caps or mix of capital and lower-case?
Mixed case
If Map Unit = Trg
Tertiary rhyolite granite (Trg)?
Triassic granite (Trg)?
This example issue is solved if you use capital letters to represent age
Tertiary rhyolite granite (Trg)
Triassic granite (TRg)
All-caps
Second letter may conflict with other abbreviations
example – abbreviation for Cambrian
C already used for Carboniferous
could use CA for Cambrian, but t A represents Archean
cant use CM for Cambrian, conflict:
Cambrian rock (CMr)
Cambrian to Mississippian rock (CMr)
CB for Cambrian makes no conflict<br>
07
Took a stab at Option 4 (standardize abbreviations)
Asked Gitter members to weigh in<br>
08
To Do:
Can we all agree on age abbreviations? Each survey uses their own system?
What ages to include? All Subdivisions? Anthropocene too?
How are people using the Label field?<br>
09
How are people using the Label field?
All Text formatting tags
Tags only for special characters
No tags, but note in metadata about using FGDC GeoAge font for Label field<br>
