Sunday, December 31, 2017

Adult size in Scaphites

Three adult specimens of Scaphites showing the size range.  The two on the left are probably progenetic dwarfs of contemporary full size species.  Pteroscaphites pisinnus (far left) from the Scaphites whifieldi Zone, undetermined example (center) from the Prionocyclus hyatti Zone, and Scaphites carlilensis (right) from the Prinocyclus macombi Zone.  Only adults grow a hook for a body chamber.  Sexual dimorphs have been reported for most Scaphites, with microconchs being about the same size as Macroconchs but a lot less inflated.  The genus Yezoites may show dimorphic size differences comparable to that shown above, but that is for another post.

Monday, December 18, 2017

Ugly Map Colors

Too bad modern geology is taking a step backward with their geologic mapping colors.  I have yet to see an official standard calling out the new colors. You used to get a choice at stratigraphy.org, but no more.  Are they using a traditional system for the sake of tradition under the guise of priority.  This is almost as bad as illustrating ammonoids upside down of their assumed life position (again, mainly tradition).  It is like moving away from Metric Units back to Imperial feet and inches.  Why random colors?  The divisions are called Systems or in the case of rock units, Series.  Why wouldn't the colors look better in order or series?

CGMW

USGS

Quarternary


Neogene


Paleogene


Cretaceous


Jurassic


Triassic


Permian


Pennsylvanian


Mississippian


Devonian


Silurian


Ordovician


Cambrian


“preCambrian”

I tried to match the colors from the latest time scale from www.stratigraphy.org for the CGMW colors, and from the pdf linked below for the USGS colors

Hopefully no rocks on your map from the Cretaceous, Mississippian, or Cambrian come in contact with each other, they would be difficult to separate.

CGMW

USGS

Cretaceous


Mississippian


Cambrian


How about Jurassic, Pennsylvanian, and Silurian?

CGMW

USGS

Jurassic


Pennsylvanian


Silurian


Why even use colors to distinguish different Formations or Series if they are so similar to others?

Are the old Standards to be changed?
The USGS published some suggestions back in 2005.
And the Geologic Data Subcommittee (GDS) of the Federal Geographic Data Committee (FGDC)
published standards for GIS in 2008.
Are these going to change?  Will they use the random color system of the CGMW?

Some pages (just a few I've run across so far) already using the CGMW colors:
This map (from SVP) was modified from an existing map and strat column with the new colors.
Macrostrat using the new colors.

I think it is unfortunate that these new colors are being adopted, and it seems to me a step backwards.

Whine over :(