Te Ahumata (White Cliffs), Great Barrier Island, Auckland Region, New Zealandi
Regional Level Types | |
---|---|
Te Ahumata (White Cliffs) | - not defined - |
Great Barrier Island | Island |
Auckland Region | Region |
New Zealand | Country |
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Latitude & Longitude (WGS84):
36° 13' 52'' South , 175° 25' 13'' East
Latitude & Longitude (decimal):
Mindat Locality ID:
302723
Long-form identifier:
mindat:1:2:302723:6
GUID (UUID V4):
a074cd75-2787-4328-ba75-1dc2c92a7f81
Silver with some gold was found in the southern part of the island in 1893 alternatively known as Te Ahumata or White Cliffs, centred on a large grass covered mountain near Whangaparapara. Until 1908 about 1300 kg of silver/gold bullion was produced.
The discoverers were the Sanderson brothers early 1893, showing a lode trending east-west, dipping south, 2-6 feet wide. It was hosted in country rock of soft blue to whitish sandstone, the lode including a 2 foot wide kaolin seam along the Footwall. Several more lodes were subsequently uncovered in the surrounding area.
It appears during much of the 1890's mining was restricted to prospectors, and small companies with limited capital, covering a range of leases. In 1897, named leases included Mount Argentum, the Great Barrier Excelsior formerly known as White Cliffs, Aotea, Bonanza, Comstock, Junction Barrier, Silver King, Great Barrier Eastern, Great Barrier East. From this time the Great Barrier Gold and Silver Estates Company began consolidating leases, and from 1899 constructed a 20 stamp battery, opening in 1900 and lasting until 1908.
Then no mining took place until 1971 when Consolidated Silver Mining Company quarried 900 tonnes of quartz from the Iona section. Several companies and individuals explored the area until the mid 1980's. A comprehensive study of the deposits is potentially lacking, and any exploration even purely scientific in nature, may meet local opposition, for fear it will lead to mining. Indications are the deposits are complex containing base metals, sulphosalts, seleniferous and selenide minerals and stibnite.
Mineralisation is found in quartz veins in hydrothermally altered Miocene andesites, caped by silicified late Miocene-Pliocene rhyolitic pyroclastic rocks and volcaniclastic sediments. Early alteration resulted in adularia-illite, followed outwards by illite-smectite, and distal Ca smectite.
Silver is found as small quantities of native silver, much chlorargyrite which initially is creamy white however on exposure to air turns purple then black, and pyragyrite. Silver selenide minerals naumannite and aguilarite are found, and many of the lodes contain much stibnite. Galena, sphalerite and chalcopyrite is found at depth. Also mentioned is pyrite, electrum, tetrahedrite, trace pyrrhotite. Species listed under Lees Reef are also possible for neighbouring areas.
Since mining has stopped the lode has gained almost mythical status with comments like a mountain of silver worth billions of dollars being bandied about with little supporting evidence. It is assumed if such a treasure remained mining would not have stopped in 1908, or at least mining would have resumed shortly after.
Plans to allow exploration work in 2010 drew considerable opposition from the local community.
The Mindat co-ordinates are the site of the battery remains. Various tunnels are said to be hidden in the surrounding scrub.
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Standard Detailed Gallery Strunz Chemical ElementsMineral List
Mineral list contains entries from the region specified including sub-localities24 valid minerals.
Rock Types Recorded
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Rock list contains entries from the region specified including sub-localities
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Alphabetical List Tree DiagramDetailed Mineral List:
β Acanthite Formula: Ag2S Localities: References: |
β Aguilarite Formula: Ag4SeS Localities: References: |
β Argyrodite Formula: Ag8GeS6 Localities: References: |
β Arsenopyrite Formula: FeAsS Localities: References: |
β Cervantite Formula: Sb3+Sb5+O4 References: Rod Martin CollectionIdentified by Rod Martin: Visual Identification |
β Chalcopyrite Formula: CuFeS2 Localities: References: |
β Chlorargyrite Formula: AgCl |
β Galena Formula: PbS Localities: References: |
β Gold Formula: Au Localities: References: |
β Gold var. Electrum Formula: (Au,Ag) |
β Kaolinite Formula: Al2(Si2O5)(OH)4 |
β 'K Feldspar' |
β 'K Feldspar var. Adularia' Formula: KAlSi3O8 |
β Marcasite Formula: FeS2 Localities: References: |
β Melanterite Formula: Fe2+(H2O)6SO4 · H2O References: Rod Martin CollectionIdentified by Rod Martin: Visual Identification |
β Muscovite Formula: KAl2(AlSi3O10)(OH)2 |
β Muscovite var. Illite Formula: K0.65Al2.0[Al0.65Si3.35O10](OH)2 |
β Naumannite Formula: Ag2Se Localities: References: |
β Polybasite Formula: [Ag6Sb2S7][Ag9CuS4] Localities: References: |
β Proustite Formula: Ag3AsS3 Localities: References: |
β Pyrargyrite Formula: Ag3SbS3 Localities: References: |
β Pyrite Formula: FeS2 Localities: References: |
β Pyrrhotite Formula: Fe1-xS |
β Quartz Formula: SiO2 References: Rod Martin CollectionIdentified by Rod Martin: Visual Identification |
β Realgar Formula: As4S4 Localities: References: |
β Silver Formula: Ag Localities: References: |
β 'Smectite Group' Formula: A0.3D2-3[T4O10]Z2 · nH2O |
β Sphalerite Formula: ZnS Localities: References: |
β 'Stibiconite' Formula: Sb3+Sb5+2O6(OH) References: Rod Martin CollectionIdentified by Rod Martin: Visual Identification |
β Stibnite Formula: Sb2S3 |
β 'Tetrahedrite Subgroup' Formula: Cu6(Cu4C2+2)Sb4S12S Localities: References: |
List of minerals arranged by Strunz 10th Edition classification
Group 1 - Elements | |||
---|---|---|---|
β | Silver | 1.AA.05 | Ag |
β | Gold var. Electrum | 1.AA.05 | (Au,Ag) |
β | 1.AA.05 | Au | |
Group 2 - Sulphides and Sulfosalts | |||
β | Acanthite | 2.BA.35 | Ag2S |
β | Aguilarite | 2.BA.55 | Ag4SeS |
β | Naumannite | 2.BA.55 | Ag2Se |
β | Argyrodite | 2.BA.70 | Ag8GeS6 |
β | Sphalerite | 2.CB.05a | ZnS |
β | Chalcopyrite | 2.CB.10a | CuFeS2 |
β | Pyrrhotite | 2.CC.10 | Fe1-xS |
β | Galena | 2.CD.10 | PbS |
β | Stibnite | 2.DB.05 | Sb2S3 |
β | Pyrite | 2.EB.05a | FeS2 |
β | Marcasite | 2.EB.10a | FeS2 |
β | Arsenopyrite | 2.EB.20 | FeAsS |
β | Realgar | 2.FA.15a | As4S4 |
β | Proustite | 2.GA.05 | Ag3AsS3 |
β | Pyrargyrite | 2.GA.05 | Ag3SbS3 |
β | 'Tetrahedrite Subgroup' | 2.GB.05 | Cu6(Cu4C2+2)Sb4S12S |
β | Polybasite | 2.GB.15 | [Ag6Sb2S7][Ag9CuS4] |
Group 3 - Halides | |||
β | Chlorargyrite | 3.AA.15 | AgCl |
Group 4 - Oxides and Hydroxides | |||
β | Quartz | 4.DA.05 | SiO2 |
β | Cervantite | 4.DE.30 | Sb3+Sb5+O4 |
β | 'Stibiconite' | 4.DH.20 | Sb3+Sb5+2O6(OH) |
Group 7 - Sulphates, Chromates, Molybdates and Tungstates | |||
β | Melanterite | 7.CB.35 | Fe2+(H2O)6SO4 Β· H2O |
Group 9 - Silicates | |||
β | Muscovite | 9.EC.15 | KAl2(AlSi3O10)(OH)2 |
β | var. Illite | 9.EC.15 | K0.65Al2.0[Al0.65Si3.35O10](OH)2 |
β | Kaolinite | 9.ED.05 | Al2(Si2O5)(OH)4 |
Unclassified | |||
β | 'K Feldspar var. Adularia' | - | KAlSi3O8 |
β | '' | - | |
β | 'Smectite Group' | - | A0.3D2-3[T4O10]Z2 Β· nH2O |
List of minerals for each chemical element
Localities in this Region
- Auckland Region
- Great Barrier Island
- Te Ahumata (White Cliffs)
- Great Barrier Island
Other Regions, Features and Areas containing this locality
Australian PlateTectonic Plate
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Te Ahumata, Great Barrier Island, Auckland Region, New Zealand