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"Foothold Cleft", Airline Railroad, East Hampton (Chatham), Middlesex Co., Connecticut, USAi
Regional Level Types
"Foothold Cleft"- not defined -
Airline Railroad- not defined -
East Hampton (Chatham)- not defined -
Middlesex Co.County

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Lock Map
Latitude & Longitude (WGS84): 41° 34' 32'' North , 72° 29' 47'' West
Latitude & Longitude (decimal): 41.57556,-72.49639
GeoHash:G#: drkkw29ep
Köppen climate type:Dfb : Warm-summer humid continental climate
Nearest Settlements:
East Hampton2,691 (2017)0.5km
Lake Pocotopaug3,436 (2017)2.8km
Terramuggus1,025 (2017)7.0km
Moodus1,413 (2017)8.9km
Higganum1,698 (2017)10.1km

A mere 50ft from the tourmaline occurrence on the airline trail, a long cavity of quartz, andulari, and pyrite was found by mistake by Rowan Lytle while climbing around, looking at the rock faces. Clear, terminated crystals up to 4cm were found, and many had chlorite and kaolinite inclusions.

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:

'Chlorite Group'
Habit: grains in quartz and host rock
Colour: green-grey
Reference: Rowan M. Lytle Collection
Formula: α-Fe3+O(OH)
Reference: Rowan M. Lytle Collection
Formula: C
Reference: Rowan M. Lytle Collection
Formula: Al2(Si2O5)(OH)4
Reference: Rowan M. Lytle Collection
'K Feldspar'
Reference: Rowan M. Lytle Collection
'K Feldspar var: Adularia'
Formula: KAlSi3O8
Reference: Rowan M. Lytle Collection
Formula: FeS2
Reference: Rowan M. Lytle Collection
Formula: SiO2
Habit: well formed, often doubly terminated
Colour: transparent or milky
Description: Some have phantoms of kaolinite or chlorite. Size ranges from 3mm to 3cm.
Reference: Rowan M. Lytle Collection

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Group 2 - Sulphides and Sulfosalts
Group 4 - Oxides and Hydroxides
Group 9 - Silicates
Unclassified Minerals, Rocks, etc.
'Chlorite Group'-
'K Feldspar'-
'var: Adularia'-KAlSi3O8

List of minerals arranged by Dana 8th Edition classification

Semi-metals and non-metals
Group 2 - SULFIDES
AmBnXp, with (m+n):p = 1:2
Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Unclassified Minerals, Mixtures, etc.
'Chlorite Group'-
'K Feldspar'-
'var: Adularia'-KAlSi3O8

List of minerals for each chemical element

H KaoliniteAl2(Si2O5)(OH)4
H Goethiteα-Fe3+O(OH)
C GraphiteC
O QuartzSiO2
O K Feldspar (var: Adularia)KAlSi3O8
O KaoliniteAl2(Si2O5)(OH)4
O Goethiteα-Fe3+O(OH)
Al K Feldspar (var: Adularia)KAlSi3O8
Al KaoliniteAl2(Si2O5)(OH)4
Si QuartzSiO2
Si K Feldspar (var: Adularia)KAlSi3O8
Si KaoliniteAl2(Si2O5)(OH)4
S PyriteFeS2
K K Feldspar (var: Adularia)KAlSi3O8
Fe PyriteFeS2
Fe Goethiteα-Fe3+O(OH)

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

Devonian - Silurian
358.9 - 443.8 Ma

ID: 3186140
Paleozoic sedimentary and volcanic rocks

Age: Paleozoic (358.9 - 443.8 Ma)

Lithology: Mudstone-carbonate-sandstone-conglomerate

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Ordovician - Cambrian
443.8 - 541 Ma

ID: 2851357
Brimfield Schist (Includes Hamilton Resevoir Formation)

Age: Paleozoic (443.8 - 541 Ma)

Stratigraphic Name: Brimfield Schist; Hamilton Resevoir Formation

Description: Gray, rusty-weathering, medium- to coarse-grained, interlayered schist and gneiss, composed of oligoclase, quartz, K-feldspar, and biotite, and commonly garnet, sillimanite, graphite, and pyrrhotite. K-feldspar partly as augen 1 to 3 cm across. Minor layers and lenses of hornblende- and pyroxene-bearing gneiss, amphibolite, and calc-silicate rock.

Comments: Part of Eastern Uplands; Iapetus (Oceanic) Terrane - Merrimack Synclinorium; Brimfield Schist and equivalent formations (includes Tatnic Hill Formation) (Upper? and Middle Ordovician). The age of the Brimfield Group in this area is Cambrian(?) based on the intrusion of 440 my Hedgehog Hill gneiss in the top of the Hamilton Reservoir Formation in the upper part of the Brimfield, although the top of the Brimfield may be Ordovician or older Paleozoic (Pease, 1989) per CT013. Original map source: Connecticut Geological and Natural History Survey, DEP, in cooperation with the U.S. Geological Survey, 2000, Bedrock Geology of Connecticut, shapefile, scale 1:50,000

Lithology: Major:{schist,gneiss}, Minor:{amphibolite,calc silicate rock}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License


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Rowan M. Lytle Collection

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