Tertiary Channels of Ca map

[Alex Burke]

I tried to overlay the old sketch of the tertiary channels of Ca into Google Earth, it didn't line up too well and the margin of error is very high, but here it is for entertainment purposes I wouldn't follow this map to closely

View attachment Ca Tertiary Sketch Overlay2.kmz

Link to original map with the map key ftp://ftp.conservation.ca.gov/pub/dmg/pubs/cg/1965/18_03.pdf

Interesting links on Ca tertiary channels Locating Tertiary

DEAD RIVERS OF CALIFORNIA: Tertiary Channels rich in gold nuggets

I realized after making this overlay there are possibly better more modern sketches to overlay in this paper, so I'll try another sometime with maybe better results.
http://ucmp.berkeley.edu/science/profiles/garside_paper.pdf

 

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[russau]

Lots of good reading ! Thankyou.

 

[Clay Diggins]

That map is in an entirely different projection than the Google Earth interface. You will need to reproject the map to google's made up projection.

The Clark map you are showing will never be very accurate because it's a greatly reduced copy of the original 1932 Jenkins map. Clark does a good job of explaining the basics of the channels but the map graphics are only generalized. We found one of the two or three Jenkins originals still in existence at the New Mexico School of Mines Federal Repository Library in Socorro, New Mexico.

We were allowed to take the original book and large folio for a month for reproduction as we are visiting geologists at that University. The original map was around 3 x 4 foot and has a lot more detail than the later copies. We managed to reproduce the map, reproject it, digitize it and include the results in our MinerDiggins American River FootPrints software.

The Jenkins map will probably never be reproduced full size again. The existing copies are very fragile and all the copies we know of are no longer available for study. There are better maps and information available though.

For the American River FootPrints we found the 1932 Olaf P. Jenkins Tertiary Map in the 1932 Report of the State Mineralogist - Volume 28 useful. That report also relies on the excellent work of Waldemar Lindgren. That map is fairly general also but we did digitize the results based on the Jenkins report for the FootPrints. We have found no digital copies of that map. It was a large folded "tip in" at the back of the report.

Probably the best tertiary mapping available for the area is the limited area report by Deb K. Chandra in 1961. You will find that report in the California Division of Mines, California Special Report 67 - Geology and Mineral Deposits of the Colfax and Foresthill Quadrangles, California. We have also reprojected and digitized that information for the FootPrints maps. The map was in a pocket and is not very readable but it has better detail than any other and the Chandra report is the best we've found. Unfortunately we've never found a digitized copy of the report with the map included on the internet. That map was also folded so finding readable copies is difficult.

You can find those maps and 116 reports totaling more than 40,000 pages in the Land Matters California Treasures DVD. Most of those materials could be searched out on the internet but the DVD has an index and is searchable as well as being OCR for copy and paste of text and images. It's a very handy research tool if you are studying California mining and mineralogy.

Heavy Pans

 

[Alex Burke]

Good info as always. Mostly I wanted to post these links because I prospected for decades not knowing I was digging on 100's of feet of useless gravel I figure at least the links may be educational to poor souls like myself. I agree my map sucks someone needs to post a good one haha.

I think it would maybe work better just doing a small section at a time possibly? I am interested in how to reproject the map to googles projection and getting better at this stuff so I will google that or if you have a link explaining it that would be great. Thanks as always I learn a lot from you always appreciate your knowledge.

 

[Clay Diggins]

The best place to start for serious mapping is to get a copy of Qgis. It's the most advanced mapping program available, there is a version to run on each operating system and it's free.

There is a pretty big learning curve to advanced mapping but luckily there is good documentation and good support in the various versions. Dig in and try some basic stuff. You can output your work in most formats including the google fake projections and funky file formats. Being it's free just make backup copies of all your map data and bang away. After awhile it will seem easy to do what you want and you will come to love the quick accurate response, speed, cool tools and easy modifications.

Heavy Pans

 

[Oakview2]

Oldie but a goodie.



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