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Bishop's Tawton, North Devon, Devon, England, UKi
Regional Level Types
Bishop's TawtonCivil Parish
North DevonDistrict
DevonCounty
EnglandConstituent Country
UKCountry

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PhotosMapsSearch
08901890017272353155946.jpg
Collecting phosphate minerals at Downrow Quarry

Downrew Quarry, Bishop's Tawton, North Devon, Devon, England, UK
04632740017272353169329.jpg
Cacoxenite etc. plate as removed from the quarry wall.

Downrew Quarry, Bishop's Tawton, North Devon, Devon, England, UK
Mindat Locality ID:
298942
Long-form identifier:
mindat:1:2:298942:9
GUID (UUID V4):
0
Other Languages:
French:
Bishop's Tawton, North Devon, Devon, Angleterre, Royaume-Uni
German:
Bishop's Tawton, North Devon, Devon, England, Vereinigtes Königreich
Italian:
Bishop's Tawton, North Devon, Devon, Inghilterra, Regno Unito
Spanish:
Bishop's Tawton, North Devon, Devon, Inglaterra, Reino Unido
Basque:
Bishop's Tawton, Devon, Ingalaterra, Erresuma Batua
Cebuano:
Bishop's Tawton, North Devon District, Inglatera, Hiniusang Gingharian
Dutch:
Bishop's Tawton, North Devon, Devon, Engeland, Verenigd Koninkrijk
Egyptian Arabic:
بيشوپس تاوتون, ديڤون, انجلترا, المملكه المتحده
Irish Gaelic:
Bishop's Tawton, Devon, Sasana, An Ríocht Aontaithe
Japanese:
ビショップス・トートン, 北デヴォン, デヴォン, イングランド, イギリス
Minnan / Hokkien-Taiwanese:
Bishop's Tawton, Devon, Eng-tē, Liân-ha̍p Ông-kok
Polish:
Bishop's Tawton, North Devon, Devon, Anglia, Wielka Brytania
Swedish:
Bishop's Tawton, North Devon, Devon, England, Storbritannien
Welsh:
Bishop's Tawton, Gogledd Dyfnaint, Dyfnaint, Lloegr, Y Deyrnas Unedig


Bishop's Tawton is a village and civil parish in the North Devon district of Devon, England. It is in the valley of the River Taw, about three miles south of Barnstaple.

The village sits at the foot of the western end of Codden Hill, the name locality for the Carboniferous Codden Hill Cherts, a complex of marine deep-trench deposits generally depleted of carbonates but in which phosphatic nodules abound.

The exposure of the Codden Hill Cherts extends westward as a series of low hills, finally disappearing at the coast, and extends eastward as far as South Molton. The exposure comes to surface as a series of E-W trending folds.

The beds extend below the surface for an unknown distance to the south and are eroded completely to the north.

The cherts are sparsely fossiliferous though are noted for the presence of phosphate minerals, in particular Wavellite (TL at Filleigh, to the east of Codden Hill).

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.


Mineral List

Mineral list contains entries from the region specified including sub-localities

8 valid minerals.

Rock Types Recorded

Note: data is currently VERY limited. Please bear with us while we work towards adding this information!

Rock list contains entries from the region specified including sub-localities

Select Rock List Type

Alphabetical List Tree Diagram

Detailed Mineral List:

ⓘ Beraunite ?
Formula: Fe3+6(PO4)4O(OH)4 · 6H2O
Habit: Massive, bladed masses.
Colour: reddish-brown to clove brown
Description: Some reddish-brown areas of a small number of specimens show the bladed forms resembling those of eleonorite. Further work is required for confirmation.
ⓘ Cacoxenite
Formula: Fe3+24AlO6(PO4)17(OH)12 · 75H2O
Habit: massive, botryoidal, encrusting
Colour: yellow
Description: Cacoxenite is found as a bright yellow encrustation in fractures in the rock of the quarry, often in association with porous quartz veins. Where it is found, it is locally abundant but is absent through most of the quarry. Larger plates showing the phosphatic mineralisation vary across the suface between clove-brown and bright yellow, occasionally to orange and red. The cacoxenite is generally between a deep yellow-brown and bright yellow.
ⓘ 'Manganese Oxides'
ⓘ 'Manganese Oxides var. Manganese Dendrites'
Habit: Dendritic - coarsely crystalline to lacy dendritic encrustations.
Colour: Black
Description: The development of manganese dendrites is particularly varied in this quarry - ranging from coarse, tangible crystals infilling fracture voids down to delicate, mossy developments across the siltstone surfaces. In places, these developments do present a particular aesthetic appeal.
ⓘ Metavivianite ?
Formula: Fe2+Fe3+2(PO4)2(OH)2 · 6H2O
Habit: blased masses
Colour: dark green
Description: A few areas of phosphatic encrustation show the colour and approximate form of metavivianite. Further work is required.
ⓘ Opal
Formula: SiO2 · nH2O
ⓘ Opal var. Common Opal
Formula: SiO2 · nH2O
Habit: none: massive
Colour: white to off-white
Fluorescence: none
Description: Redeposited silica tubes formed in cracks in the Codden Hill Cherts which host a number of phosphate species. These thin-walled tubes appear to have formed in much the same way as speleothem 'straws', and various walls and ramifications appear across the rock surfaces. These same cracks also play host to the various phosphate minerals found at this location.
ⓘ Rockbridgeite ?
Formula: (Fe2+0.5Fe3+0.5)2Fe3+3(PO4)3(OH)5
ⓘ Strengite ?
Formula: FePO4 · 2H2O
Habit: botryoidal, encrusting; massive
Colour: pale purple
Description: Areas of purple phosphatic encrustations strongly resemble strengite.
ⓘ Variscite ?
Formula: AlPO4 · 2H2O
Habit: botryoidal; encrusting
Colour: white
Description: Tiny, pale hemispheres and white encrustations have been tentatively placed as variscite. Variscite has been previously reported (unconfirmed) from this location.
ⓘ Wavellite
Formula: Al3(PO4)2(OH)3 · 5H2O
Habit: Radial hemispheres, botryoidal
Colour: bottle green to black
Description: Small clusters of generally dark hemispheres lining a cavity formerly filled with phosphatic clay. Other minerals peresent in this specimen are manganese oxides, cacoxenite and other unidentified (phosphate) minerals. The specimen was removed in the process of extracting cacoxenite plates from the quarry wall.

List of minerals arranged by Strunz 10th Edition classification

Group 4 - Oxides and Hydroxides
ⓘOpal4.DA.10SiO2 · nH2O
ⓘvar. Common Opal4.DA.10SiO2 · nH2O
Group 8 - Phosphates, Arsenates and Vanadates
ⓘRockbridgeite ?8.BC.10(Fe2+0.5Fe3+0.5)2Fe3+3(PO4)3(OH)5
ⓘStrengite ?8.CD.10FePO4 · 2H2O
ⓘVariscite ?8.CD.10AlPO4 · 2H2O
ⓘMetavivianite ?8.DC.25Fe2+Fe3+2(PO4)2(OH)2 · 6H2O
ⓘBeraunite ?8.DC.27Fe3+6(PO4)4O(OH)4 · 6H2O
ⓘCacoxenite8.DC.40Fe3+24AlO6(PO4)17(OH)12 · 75H2O
ⓘWavellite8.DC.50Al3(PO4)2(OH)3 · 5H2O
Unclassified
ⓘ'Manganese Oxides
var. Manganese Dendrites'
-
ⓘ''-

List of minerals for each chemical element

HHydrogen
Hⓘ BerauniteFe63+(PO4)4O(OH)4 · 6H2O
Hⓘ CacoxeniteFe243+AlO6(PO4)17(OH)12 · 75H2O
Hⓘ MetavivianiteFe2+Fe23+(PO4)2(OH)2 · 6H2O
Hⓘ OpalSiO2 · nH2O
Hⓘ Rockbridgeite(Fe2+0.5Fe3+0.5)2Fe33+(PO4)3(OH)5
Hⓘ StrengiteFePO4 · 2H2O
Hⓘ VarisciteAlPO4 · 2H2O
Hⓘ WavelliteAl3(PO4)2(OH)3 · 5H2O
Hⓘ Opal var. Common OpalSiO2 · nH2O
OOxygen
Oⓘ BerauniteFe63+(PO4)4O(OH)4 · 6H2O
Oⓘ CacoxeniteFe243+AlO6(PO4)17(OH)12 · 75H2O
Oⓘ MetavivianiteFe2+Fe23+(PO4)2(OH)2 · 6H2O
Oⓘ OpalSiO2 · nH2O
Oⓘ Rockbridgeite(Fe2+0.5Fe3+0.5)2Fe33+(PO4)3(OH)5
Oⓘ StrengiteFePO4 · 2H2O
Oⓘ VarisciteAlPO4 · 2H2O
Oⓘ WavelliteAl3(PO4)2(OH)3 · 5H2O
Oⓘ Opal var. Common OpalSiO2 · nH2O
AlAluminium
Alⓘ CacoxeniteFe243+AlO6(PO4)17(OH)12 · 75H2O
Alⓘ VarisciteAlPO4 · 2H2O
Alⓘ WavelliteAl3(PO4)2(OH)3 · 5H2O
SiSilicon
Siⓘ OpalSiO2 · nH2O
Siⓘ Opal var. Common OpalSiO2 · nH2O
PPhosphorus
Pⓘ BerauniteFe63+(PO4)4O(OH)4 · 6H2O
Pⓘ CacoxeniteFe243+AlO6(PO4)17(OH)12 · 75H2O
Pⓘ MetavivianiteFe2+Fe23+(PO4)2(OH)2 · 6H2O
Pⓘ Rockbridgeite(Fe2+0.5Fe3+0.5)2Fe33+(PO4)3(OH)5
Pⓘ StrengiteFePO4 · 2H2O
Pⓘ VarisciteAlPO4 · 2H2O
Pⓘ WavelliteAl3(PO4)2(OH)3 · 5H2O
FeIron
Feⓘ BerauniteFe63+(PO4)4O(OH)4 · 6H2O
Feⓘ CacoxeniteFe243+AlO6(PO4)17(OH)12 · 75H2O
Feⓘ MetavivianiteFe2+Fe23+(PO4)2(OH)2 · 6H2O
Feⓘ Rockbridgeite(Fe2+0.5Fe3+0.5)2Fe33+(PO4)3(OH)5
Feⓘ StrengiteFePO4 · 2H2O

Geochronology

Mineralization age: Carboniferous : 341 Ma to 326.4 ± 1.6 Ma

Important note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.

Geologic TimeRocks, Minerals and Events
Phanerozoic
 Paleozoic
  Carboniferous
   Mississippian
ⓘ Mudstone (youngest age)326.4 ± 1.6 MaDownrew Quarry, Bishop's Tawton, North Devon, Devon, England, UK
ⓘ Siltstone (youngest age)326.4 ± 1.6 MaDownrew Quarry, Bishop's Tawton, North Devon, Devon, England, UK
ⓘ Greywacke (youngest age)326.4 ± 1.6 MaDownrew Quarry, Bishop's Tawton, North Devon, Devon, England, UK
ⓘ Mudstone (oldest age)341 MaDownrew Quarry, Bishop's Tawton, North Devon, Devon, England, UK
ⓘ Siltstone (oldest age)341 MaDownrew Quarry, Bishop's Tawton, North Devon, Devon, England, UK
ⓘ Greywacke (oldest age)341 MaDownrew Quarry, Bishop's Tawton, North Devon, Devon, England, UK

Fossils

This region is too big or complex to display the fossil list, try looking at smaller subregions.

Other Databases

Wikipedia:https://en.wikipedia.org/wiki/Bishop%27s_Tawton
Wikidata ID:Q4917449
GeoNames ID:2655559

Localities in this Region

Other Regions, Features and Areas that Intersect

British and Irish IslesGroup of Islands
Eurasian PlateTectonic Plate
UK

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