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Pontlyfni meteorite, Clynnog, Gwynedd, Wales, UKi
Regional Level Types
Pontlyfni meteoriteMeteorite Fall Location
Clynnog- not defined -
Gwynedd- not defined -

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Latitude & Longitude (WGS84): 53° 2' 11'' North , 4° 19' 10'' West
Latitude & Longitude (decimal): 53.03639,-4.31972
GeoHash:G#: gckvtwyrr
Locality type:Meteorite Fall Location
Meteorite Class:Winonaite meteorite
Meteoritical Society Class:Winonaite
Metbull:View entry in Meteoritical Bulletin Database
Köppen climate type:Cfb : Temperate oceanic climate
Nearest Settlements:
Penygroes1,793 (2017)3.1km
Talysarn1,086 (2017)4.6km
Groeslon880 (2017)5.4km
Garndolbenmaen101 (2012)8.8km
Bontnewydd951 (2017)9.5km
Other/historical names associated with this locality:Caernarvonshire

Winonaite (Primitive Achondrite); Shock Level-S2.
Fell 14 April 1931, 157 g.

Although the main mass is reported to have fallen into the sea, a moderately small portion was recovered. The Pontlyfni meteorite exhibits a fine-grained texture rich in both magnesium-rich olivine (Fa1) and pyroxene (Fs2). Troilite is also relatively abundant. Minor amounts of clinopyroxene, plagioclase and Fe-Ni metal are also found as well as rare relic chondrules. For several decades Pontlyfni was recognized as a somewhat unusual meteorite, but its similarities to a small group of primitive achondrites called Winonaites were not recognized until relatively recently. The Winonaites have very reduced mineralogical assemblages and their oxygen isotopes appear to be closely related to those found in the silicate inclusions of the IAB complex Irons. As most Winonaites lack chondrules, but have a chemical compositions that belies extensive differentiation they have been deemed 'primitive achondrites.' However, the overall similarities between Pontlyfni and other Winonaites are compelling and so Pontlyfni is now classified as a Winonaite. This has two unusually peculiar consequences. The belated classification makes Pontlyfni the only observed Winonaite fall (whenever possible, meteorite prototypes are selected from the members whose falls were observed). And, Pontlyfni is now a chondrule-containing meteorite stone formally assigned to the class of 'achondrites.'

While all Winonaites have fine-grained reduced mineralogical assemblages, Pontlyfni's constituents are more olivine-rich, its textures are even finer-grained, and its mineralogical assemblages more reduced than those of other Winonaites. Odd irregular aggregates are also found. Some of Pontlyfni's features have been attributed to incipient partial melting — but Pontlyfni's history and its precise relationship to other Winonaites are still matters of ongoing discussions.

Regions containing this locality

Eurasian PlateTectonic Plate
British IslesGroup of Islands

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Mineral List

4 valid minerals.

Meteorite/Rock Types Recorded

Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!

Select Rock List Type

Alphabetical List Tree Diagram

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Group 2 - Sulphides and Sulfosalts
Group 9 - Silicates
Unclassified Minerals, Rocks, etc.
'Albite-Anorthite Series'-
'Clinopyroxene Subgroup'-
'Fayalite-Forsterite Series'-
'Pyroxene Group'-

List of minerals arranged by Dana 8th Edition classification

Semi-metals and non-metals
Group 2 - SULFIDES
AmXp, with m:p = 1:1
Group 51 - NESOSILICATES Insular SiO4 Groups Only
Insular SiO4 Groups Only with all cations in octahedral [6] coordination
Group 65 - INOSILICATES Single-Width,Unbranched Chains,(W=1)
Single-Width Unbranched Chains, W=1 with chains P=2
Unclassified Minerals, Mixtures, etc.
'Albite-Anorthite Series'-
'Clinopyroxene Subgroup'-
'Fayalite-Forsterite Series'-
'Pyroxene Group'-

List of minerals for each chemical element

C GraphiteC
O EnstatiteMgSiO3
O ForsteriteMg2SiO4
Mg EnstatiteMgSiO3
Mg ForsteriteMg2SiO4
Si EnstatiteMgSiO3
Si ForsteriteMg2SiO4
S TroiliteFeS
Fe TroiliteFeS

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

419.2 - 443.8 Ma

ID: 3185808
Paleozoic sedimentary rocks

Age: Silurian (419.2 - 443.8 Ma)

Lithology: Sedimentary rocks

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]

443.8 - 485.4 Ma

ID: 3148570
Ordovician limestone

Age: Ordovician (443.8 - 485.4 Ma)

Lithology: Limestone

Reference: Asch, K. The 1:5M International Geological Map of Europe and Adjacent Areas: Development and Implementation of a GIS-enabled Concept. Geologisches Jahrbuch, SA 3. [147]

Early Cambrian
511 - 541 Ma

ID: 2030875
Lower Cambrian Rocks (Undifferentiated)

Age: Cambrian (511 - 541 Ma)

Lithology: Mudstone, siltstone and sandstone

Reference: British Geological Survey. DiGMapGB-625. British Geological Survey ©NERC. [23]

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


Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Kallemeyn, G. W. (1996) Pontlyfni: Not Just Another Winonaite. Meteoritics & Planetary Science 31 (4S): A68-A69. (July 1996)
Benedix, G. K., McCoy, T. J., Keil, K., Bogard, D. D. & Garrison, D. H. (1998) A petrologic and isotopic study of winonaites: evidence for early partial melting, brecciation, and metamorphism. Geochimica et Cosmochimica Acta 62 (14): 2535-2553. (July 1998)
Grady, M. M. (2000). Catalogue of Meteorites (5/e). Cambridge University Press: Cambridge, New York, Oakleigh, Madrid, Cape Town. 690 pages.
Floss, C., Crozaz, G., Jolliff, B., Benedix, G. & Colton, S. (2008) Evolution of the winonaite parent body: Clues from silicate mineral trace element distributions. Meteoritics & Planetary Science 43 (4): 657-674. (April 2008)

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