Post by Admin on Mar 6, 2023 20:19:15 GMT -7
2023-3-6
Change of Mind. I had convinced myself that William Barbee was right back in 1875, that the silver had come up from a deeper source.
I searched and found a possible source - the Alamo Impact in Nevada.
That was not the source. IF it had been, silver would have been found in the intervening pet wood layers of the Shinarump and Chinle.
So where DID the SILVER come from?
It was part of the Midas Comet Impact the geologists have erroneously labeled "The Sevier Orogeny."
That 300 mile diameter "Dirty Water Balloon" ended Jurassic Time as it created a 300 mile wide mineral belt path of wealth from northwest Canada to Tierra Del Fuego at the tip of South America.
Silver Reef was just a side touch along the way.
Following the impact and sinking of the Brand New Rocky Mountains (the Eastern Crater Rim), the Laramide Orogeny repeated the silver bearing layers 3 times.
Change of Mind. I had convinced myself that William Barbee was right back in 1875, that the silver had come up from a deeper source.
I searched and found a possible source - the Alamo Impact in Nevada.
That was not the source. IF it had been, silver would have been found in the intervening pet wood layers of the Shinarump and Chinle.
So where DID the SILVER come from?
It was part of the Midas Comet Impact the geologists have erroneously labeled "The Sevier Orogeny."
That 300 mile diameter "Dirty Water Balloon" ended Jurassic Time as it created a 300 mile wide mineral belt path of wealth from northwest Canada to Tierra Del Fuego at the tip of South America.
Silver Reef was just a side touch along the way.
ABSTRACT
The Silver Reef mining area in southwestern Utah contains the only known occurrence in the United States of commercial bodies of silver ore with minor copper-uranium-vanadium minerals in sandstone. The ore bodies are restricted to the Silver Reef sandstone member of the upper Triassic Chinle formation and occur on the limbs and nose of a major anticline and a subsidiary anticline and syncline. A newly recognized north trending normal fault and a thrust fault with a minimum eastward displacement of 1500 feet repeat the ore horizon three times. No constant relationship exists between the mineralization and the folds or faults.
Silver, copper, and minor gold values in a bentonite 300 feet below the ore-bearing horizon, minerals of these metals and lense-like bentonitic shales in the Silver Reef sandstone, and other known occurrences of notable metal content in volcanic tuffs suggest a new theory of origin for these unusual deposits. It is concluded that the metals were primary constituents of original volcanic tuffs in Triassic time; that these metals were dissolved and/or mechanically transported by streams eroding the tuffaceous sediments; that they were later deposited with the sandstone and shales of the Silver Reef area; that further concentration of the metals in the Silver Reef sandstone was by (1) solution in circulating ground water, and (2) precipitation through contact with entombed plant debris and associated bacteria in more permeable buried Triassic stream channels. Folding, erosion, and exposure of the ore horizon is assumed to have resulted in secondary enrichment of the ore deposits by meteoric waters.
The Silver Reef mining area in southwestern Utah contains the only known occurrence in the United States of commercial bodies of silver ore with minor copper-uranium-vanadium minerals in sandstone. The ore bodies are restricted to the Silver Reef sandstone member of the upper Triassic Chinle formation and occur on the limbs and nose of a major anticline and a subsidiary anticline and syncline. A newly recognized north trending normal fault and a thrust fault with a minimum eastward displacement of 1500 feet repeat the ore horizon three times. No constant relationship exists between the mineralization and the folds or faults.
Silver, copper, and minor gold values in a bentonite 300 feet below the ore-bearing horizon, minerals of these metals and lense-like bentonitic shales in the Silver Reef sandstone, and other known occurrences of notable metal content in volcanic tuffs suggest a new theory of origin for these unusual deposits. It is concluded that the metals were primary constituents of original volcanic tuffs in Triassic time; that these metals were dissolved and/or mechanically transported by streams eroding the tuffaceous sediments; that they were later deposited with the sandstone and shales of the Silver Reef area; that further concentration of the metals in the Silver Reef sandstone was by (1) solution in circulating ground water, and (2) precipitation through contact with entombed plant debris and associated bacteria in more permeable buried Triassic stream channels. Folding, erosion, and exposure of the ore horizon is assumed to have resulted in secondary enrichment of the ore deposits by meteoric waters.
COMMENTS REGARDING ORE GENESIS AT SILVER REEF, UTAH
by RICHARD V. WYMAN
The most recent publication on the geology of Silver Reef is that by Paul Dean Proctor (1) in which he hypothecates an origin of the silver mineralization from the leaching of Triassic volcanic tuffs, and transportation of the metals as sulfates to the seat of syngenetic deposition within the Silver Reef sandstone.
The following comments are intended principally to refute the arguments presented by Proctor, rather than let his work stand uncontested. Additional facts based upon the work of the recent operators add weight to the epigenetic origin of the orebodies from hypogene solutions.
ARGUMENTS FOR SYNGENETIC ORIGIN ANSWERED
On page 121 Proctor lists eleven points that must be considered in any theory of origin. Most of these points as presented tend to favor a syngenetic origin. They are as follows:
1.) The occurrence of silver chloride in association with copper carbonates and minor amounts of uranium-vanadium minerals and some selenium.
2.) The known areal distribution of minor silver and copper content in the St. George basin.
3.) The localization of commercial ore deposits in light colored sandstones inter- bedded-with red sandstone and shales of the Triassic Chinle formation.
4.) The common association of the metallic minerals with plant remains.
5.) The concentration of silver and copper minerals in stratigraphic units within the sandstone member.
6.) The association of silver, and to a lesser extent, copper with clay galls.
7.) The paragenetic sequence of deposition of the different minerals in the deposits.
8.) The absence of the associated intrusive rocks with the mineral deposits.
9.) The lack of silicification, sericitization, typical ore textures, and other accompaniments of hypogene deposition.
10.) The absence of recognizable feeder channels for the different orebodies.
11.) The occurrence of silver- and gold-bearing chalcocite-pyrite concretions in the bentonitic shale 310 feet below the Silver Reef sandstone.
CONCLUSION
The theory of genesis of the Silver Reef mineralization from a syngenetic process is doubtful on the basis of the evidence. The theory of genesis from the leaching of underlying bentonitic shales appears impossible from a logical approach, as well as from the field evidence.
An epigenetic origin for the orebodies fits the facts, and is especially substantiated by the presence of related alteration and a relation of orebodies to post-Chinle structures. A hypogene origin for the ore solutions appears most logical in view of the epigenetic origin, presence of igneous activity in the general vicinity, and stratigraphic distribution of the known mineralization. Solutions in their migration were controlled by permeability and ore deposition by chemical favorability of the beds as well as structure.
The ore solution must have been capable of carrying silver, copper, uranium, vanadium, gold, selenium, and sulfur. Further reconstruction of the nature of the ore solution would be a worthwhile step in the study of the ore genesis.
by RICHARD V. WYMAN
The most recent publication on the geology of Silver Reef is that by Paul Dean Proctor (1) in which he hypothecates an origin of the silver mineralization from the leaching of Triassic volcanic tuffs, and transportation of the metals as sulfates to the seat of syngenetic deposition within the Silver Reef sandstone.
The following comments are intended principally to refute the arguments presented by Proctor, rather than let his work stand uncontested. Additional facts based upon the work of the recent operators add weight to the epigenetic origin of the orebodies from hypogene solutions.
ARGUMENTS FOR SYNGENETIC ORIGIN ANSWERED
On page 121 Proctor lists eleven points that must be considered in any theory of origin. Most of these points as presented tend to favor a syngenetic origin. They are as follows:
1.) The occurrence of silver chloride in association with copper carbonates and minor amounts of uranium-vanadium minerals and some selenium.
2.) The known areal distribution of minor silver and copper content in the St. George basin.
3.) The localization of commercial ore deposits in light colored sandstones inter- bedded-with red sandstone and shales of the Triassic Chinle formation.
4.) The common association of the metallic minerals with plant remains.
5.) The concentration of silver and copper minerals in stratigraphic units within the sandstone member.
6.) The association of silver, and to a lesser extent, copper with clay galls.
7.) The paragenetic sequence of deposition of the different minerals in the deposits.
8.) The absence of the associated intrusive rocks with the mineral deposits.
9.) The lack of silicification, sericitization, typical ore textures, and other accompaniments of hypogene deposition.
10.) The absence of recognizable feeder channels for the different orebodies.
11.) The occurrence of silver- and gold-bearing chalcocite-pyrite concretions in the bentonitic shale 310 feet below the Silver Reef sandstone.
CONCLUSION
The theory of genesis of the Silver Reef mineralization from a syngenetic process is doubtful on the basis of the evidence. The theory of genesis from the leaching of underlying bentonitic shales appears impossible from a logical approach, as well as from the field evidence.
An epigenetic origin for the orebodies fits the facts, and is especially substantiated by the presence of related alteration and a relation of orebodies to post-Chinle structures. A hypogene origin for the ore solutions appears most logical in view of the epigenetic origin, presence of igneous activity in the general vicinity, and stratigraphic distribution of the known mineralization. Solutions in their migration were controlled by permeability and ore deposition by chemical favorability of the beds as well as structure.
The ore solution must have been capable of carrying silver, copper, uranium, vanadium, gold, selenium, and sulfur. Further reconstruction of the nature of the ore solution would be a worthwhile step in the study of the ore genesis.
Silver, copper, uranium, vanadium, gold, selenium, and sulfur are the Midas Comet Signature elements from Canada to Upheaval Dome in Utah.
Comet Eye View of Silver Reef from NW to SE.
Following the impact and sinking of the Brand New Rocky Mountains (the Eastern Crater Rim), the Laramide Orogeny repeated the silver bearing layers 3 times.