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Southeast Quarry, North Table Mountain, Golden, Golden Mining District, Jefferson Co., Colorado, USAi
Regional Level Types
Southeast Quarry- not defined -
North Table MountainMountain
Golden- not defined -
Golden Mining DistrictMining District
Jefferson Co.County

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Latitude & Longitude (WGS84):
39° 46' 15'' North , 105° 12' 21'' West
Latitude & Longitude (decimal):
Nearest Settlements:
Golden20,330 (2017)2.2km
Applewood7,160 (2011)4.0km
West Pleasant View3,840 (2011)4.9km
East Pleasant View356 (2011)6.4km
Arvada115,368 (2017)10.7km

This is one of only 2 localities open for collecting on North Table Mountain. It is located on the corner of highway 58 and Easley Road. There is a trail going up along the road cut on highway 58, which then forks E to the quarry. The Quarry is almost directly above the road cut, at the base of the cliff at the top of N. Table Mountain.

The North Table Mountain mesa contains 4 separate lava flows. These flows are shoshonite (K-rich basalt) porphyry erupted fluidly from vents a short distance to the north. The eruptive sites are now eroded; their remnants are exposed as plugs just south of the Ralston Reservoir. The volcanic activity took place in the early Paleocene, approximately 64 ma. Dating indicates that all 4 flows were erupted during an interval of slightly less than 1 ma (Drewes, 2008).

In recent years the most prolific mineral collecting site has been an old quarry in the capping flows, 3 and 4, along the south side of the mesa directly above a prominent highway cut constructed in the late 1960’s. This is referred to as the Southeast Quarry. At this site the top 25 feet of Flow 3 are highly oxidized and amygdaloidal. The collectible material is the substantial amount of rubble on the quarry floor containing boulders of all sizes up to some well in excess of 20 tons. Amygdaloidal cavities in the rubble boulders are commonly up to several inches but may occasionally be 8 inches or larger. That after many, many years of collecting there is still much material to attack is a testament to the tenacity of the rock.

In some areas, the famous copper/zeolite-rich basalts of New Jersey for example, alteration and secondary mineral distributions within amygdaloidal horizons, as well as other mineralized structures, are systematic. They reflect many factors; principally permeability, fluid flux, proximity to the fluid source, crystallinity of the country rock, temperature and the changes in these factors through time. This author is not aware of any study of the size distribution of amygdules in the upper part of Flow 3, of systematic variation of alteration or of the distribution minerals within the amygdaloidal horizon at the Southeast quarry or elsewhere in the Table Mountain area.

Regions containing this locality

North America PlateTectonic Plate

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Mineral List

5 valid minerals.

Detailed Mineral List:

Formula: Na(AlSi2O6) · H2O
Reference: Simon and Schuster's Rocks & Minerals.
Reference: warren cummings (2009), field experience 1965-77
Formula: CaCO3
Reference: warren cummings (2009), field experience 1965-77
Formula: (Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Reference: Simon and Schuster's Rocks & Minerals.
Formula: CaAl2Si3O10 · 6H2O
Reference: Jason Evans Collection
Reference: warren cummings (2009), field experience 1965-77
Formula: NaCa2[Al5Si5O20] · 6H2O
Reference: Simon and Schuster's Rocks & Minerals.

List of minerals arranged by Strunz 10th Edition classification

Group 5 - Nitrates and Carbonates
Group 9 - Silicates
Analcime9.GB.05Na(AlSi2O6) · H2O
Chabazite-Ca9.GD.10(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Cowlesite9.GG.05CaAl2Si3O10 · 6H2O
Thomsonite-Ca9.GA.10NaCa2[Al5Si5O20] · 6H2O
Unclassified Minerals, Rocks, etc.

List of minerals arranged by Dana 8th Edition classification

Group 77 - TECTOSILICATES Zeolites
Zeolite group - True zeolites
Analcime77.1.1.1Na(AlSi2O6) · H2O
Chabazite-Ca77.1.2.1(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Cowlesite77.1.5.8CaAl2Si3O10 · 6H2O
Unclassified Minerals, Mixtures, etc.
Thomsonite-Ca-NaCa2[Al5Si5O20] · 6H2O

List of minerals for each chemical element

H Thomsonite-CaNaCa2[Al5Si5O20] · 6H2O
H AnalcimeNa(AlSi2O6) · H2O
H Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
H CowlesiteCaAl2Si3O10 · 6H2O
C CalciteCaCO3
O Thomsonite-CaNaCa2[Al5Si5O20] · 6H2O
O AnalcimeNa(AlSi2O6) · H2O
O Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
O CalciteCaCO3
O CowlesiteCaAl2Si3O10 · 6H2O
Na Thomsonite-CaNaCa2[Al5Si5O20] · 6H2O
Na AnalcimeNa(AlSi2O6) · H2O
Na Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Al Thomsonite-CaNaCa2[Al5Si5O20] · 6H2O
Al AnalcimeNa(AlSi2O6) · H2O
Al Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Al CowlesiteCaAl2Si3O10 · 6H2O
Si Thomsonite-CaNaCa2[Al5Si5O20] · 6H2O
Si AnalcimeNa(AlSi2O6) · H2O
Si Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Si CowlesiteCaAl2Si3O10 · 6H2O
K Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Ca Thomsonite-CaNaCa2[Al5Si5O20] · 6H2O
Ca Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Ca CalciteCaCO3
Ca CowlesiteCaAl2Si3O10 · 6H2O


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Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Drewes, H. (2008), Table Mountain Shoshonite Porphyry Lava Flows and Their Vents, Golden, Colorado, USGS Scientific Investigations Report 2006–5242, 28 p.

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