photos/13/0702-15_BIF_Boulder/:

By Alan Silverstein, ajs@frii.com (page updated Tue Nov 8 20:14:34 MST 2022)

Parent directory/folder = photos/13/

Another unexpected adventure! There are eight reservoirs on the North Platte River, and now I've kayaked on all six of the major ones -- adding Alcova and Seminoe on van trips with Cathie since retiring -- plus about 46 miles of the river itself in three sections. Whee!

Now about the "Big BIF" photos here; some explanation is warranted. As a rockhound, years ago I started noticing BIF = banded iron formation rocks around Glendo and Guernsey reservoirs, many miles downstream. Also locally called "ironwood" because they resemble petrified wood, but they are about 4-6 times older than any petrified wood, and much denser too. These stones are each unique, usually beautiful, and very ancient! Perhaps 2500 million (2.5 billion) years old. They take a nice tumble polish.

I've long wondered about the source of the nice BIF rocks. A few BIF outcrops I've managed to visit display only cruddier, brown/white stones. Long story short, the further upstream on the North Platte, the more and bigger and more varied the BIFs. The source appears to be the Bradley Peak area about 10 miles west of Seminoe Reservoir, although I haven't found a way yet to access it.

Well on July 2 exploring Seminoe Reservoir (where rockhounding is allowed), I found a beautiful boulder of BIF! Another long story short, I just had to snag it... And on July 12 I was back there (alone this time, without Cathie), and made it happen! I found out later it weighs 204 pounds.

Image files (Kb): (click on any image for next)

  1. 00_SeminoeSatMap.JPG (84)
  2. 0702A_BoulderInSitu.JPG (281)
  3. 0702B_BoulderInSitu.JPG (283)
  4. 0703A_EastAcrossLakeZoom.JPG (300)
  5. 0703B_BoulderOnGravelBar.JPG (292)
  6. 0703C_WholeBoulderTopView.JPG (282)
  7. 0703D_BoulderCloseup.JPG (285)
  8. 0704E_UpOnEndWithBoat.JPG (287)
  9. 0712A_BoatsAndBoulder.JPG (287)
  10. 0712B_RockOnTheRunway.JPG (288)
  11. 0712C_BoulderByTheLake.JPG (291)
  12. 0712D_BoulderInRaft.JPG (293)
  13. 0712E_WindAndWaves.JPG (297)
  14. 0712F_TimAndRockInCar.JPG (292)
  15. 0712G_WetBoulderInCar.JPG (290)
  16. 0713_ColoradoBorder.jpg (362)
  17. 0714_WashingByDriveway.JPG (284)
  18. 0715A_RockOnCart.jpg (500)
  19. 0715B_RockOnCart.jpg (526)
  20. 0715C_RockInAir.jpg (486)
  21. 0715D_DaveAndRogerLiftingRock.jpg (550)
  22. 0715E_AlanBySuzy.jpg (374)
  23. 0715F_PeopleAtPicnic.jpg (673)
  24. 0803_BIFsInFrontYard.JPG (278)