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Golden
Basic information Name: Golden
     This is an OFFICIAL meteorite name.
Abbreviation: There is no official abbreviation for this meteorite.
Observed fall: Yes, confirmed fall
Year fell: 2021
Country: Canada
Mass:help 2.39 kg
Classification
  history:
Recommended:  L/LL5    [explanation]

This is 1 of 18 approved meteorites classified as L/LL5.   [show all]
Search for other: L chondrites, L/LL chondrites, L/LL chondrites (type 4-7), LL chondrites, Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 12 Nov 2022
Writeuphelp
Writeup from MB 111:

Golden        51°17’43.3"N, 116°57’29.6"W

British Columbia, Canada

Confirmed fall: 2021 Oct 04

Classification: Ordinary chondrite (L/LL5)

History: On the evening of October 3, 2021 (23:33 local time; 05:33 UT 4 Oct 2021), a bright fireball with flares was widely observed in eastern British Columbia, western Alberta, northern Idaho and Washington, moving towards the SE over eastern British Columbia: IMO recorded the fireball as event 6241-2021. Witnesses near Golden, British Columbia, reported hearing loud booms after the fireball. One fist-sized complete 1270 g individual punched through the southwestern corner of the roof of Ms. Ruth Hamilton’s house in downtown Golden, landing on a pillow next to her head as she lay in bed. On October 10, 2021, researchers from the University of Calgary found a second, 919 g individual on the street-side in the town of Golden, BC, 1.32 km NNW of the main mass fall location.

Physical characteristics: The main mass individual is entirely covered in fusion crust with some regmalypted surfaces and one surface with thinner fusion crust through which chondrules are observed. Many surfaces of the main mass are modified with adhered roofing materials from having punctured the tin, asphalt, plywood and drywall roof during its arrival. The second individual shows 70% fusion crust and one significant broken surface revealing a light grey stone, bearing well-defined chondrules. One large ~7 mm long dark inclusion occurs on a broken face. The fusion crusted surfaces of the two individual are similar in maturity and variation in appearance. Interior stone has visible sub-mm porosity and is slightly friable. Physical Properties: The 1270 g main mass has a bulk density of 3.20±0.01 g/cm3 determined from an X-ray micro-CT scan volume and the 919 g individual has a similar bulk density. A 13.53 g specimen from the main mass provides a grain density of 3.57 ± 0.01 g/cm3 and magnetic susceptibility of log χ (× 10-9 m3/kg) = 4.72. Calculated porosity from bulk and grain densities is 10.4%. A slightly weathered cut block from the second sample returns slightly lower values: Grain density 3.49 g/cm3, bulk density 3.095 g/cm3, with calculated porosity 11.3%. Magnetic isothermal remanence saturation experiments on two chip samples (253 mg and 120 mg) return S-300 values of 0.48 and 0.55, indicating the presence of tetrataenite with high coercivity (Gattacceca et al., 2014).

Petrography: Cut surfaces reveal abundant dark chondrules and disseminated mm-sized metal grains in a green-grey matrix. In X-ray micro computed tomograpy of the main mass, metal and sulfide also occur as occasional mm-wide, irregular aggregates of ~cm area extent, confirmed in cut surfaces. Several metal-poor, X-ray absorbing, subrounded inclusions of up to cm size are observed in the main mass CT volume, likely corresponding with sulfide-bearing dark inclusions. There is no evidence for brecciation in the CT volume. In polished thin section, abundant chondrules and chondrule fragments of POP, PO, RP and BO types are moderately delineated in a recrystallized fine to medium grained feldspathic matrix. Chondrule mesostatsis is finely recrystallized as feldspar. Olivine and pyroxene grains exhibit sharp to undulatory extinction. Micro-XRD analysis (O. Benest, R Flemming, UWO) finds short diffraction streak length in olivine and pyroxene from cut surfaces, confirming shock as S2. In BSE and EDS element compositional maps, FeNi metal occurs as interstitial grains and aggregates of up to mm size. Troilite is present as abundant (5 vol%) interstitial grains and also as small inclusions in some chondrules and decorating some chondrule rims. In micro-CT volume analysis, the metal+sulfide portion of the entire main mass volume is ~8%, suggesting that the sulfide:metal ratio for the bulk meteorite is >1. Accessory matrix phases are apatite and chromite. Porosity (~10 vol%) occurs primarily as irregular, 100 to 300 μm pits between chondrules.

Geochemistry: Mineral compositions and Geochemistry: EPMA: Olivine Fa26.34±0.23 (n=53); Ca-poor pyroxene: Fs22.46±0.22 Wo1.32±0.23 (n=49); Ca-rich pyroxene: Fs8.04±0.54 Wo45.13±0.61 (n=4).

Classification: Ordinary chondrite L/LL5 (S2) W0. EPMA analyses of olivine and Ca-poor pyroxene do not discriminate between L and LL groups for this meteorite. Sulfide:metal ratio >1 and high magnetic corecivity suggest LL chondrite. Magnetic susceptibility is more consistent with L chondrite, but may suffer from inhomogeniety of metal distribution.

Specimens: Type specimen consisting of a subdivided endpiece and a polished thin section are on deposit at UWO. Main mass: R. Hamilton. A 919 g individual at UCalg.

Bibliography:
  • Gattacceca J., Suavet C., Rochette P., Weiss B.P., Winklhofer M., Uehara M. Friedrich J.M. (2014) Metal phases in ordinary chondrites: magnetic hysteresis properties and implications for thermal history. Meteorit. Planet. Sci. 49 652-676/ (link)
Data from:
  MB111
  Table 0
  Line 0:
State/Prov/County:British Columbia
Origin or pseudonym:town of Golden
Date:2021 Oct 04
Latitude:51°17'43.3"N
Longitude:116°57'29.6"W
Mass (g):2389
Pieces:2
Class:L/LL5
Shock stage:S2
Weathering grade:W0
Fayalite (mol%):27.30±0.46 (n=53)
Ferrosilite (mol%):22.46±0.22 (n=49)
Wollastonite (mol%):1.32±0.23
Magnetic suscept.:4.72
Classifier:P. McCausland (UWO), L. Hanton (UCalg), A. Hildebrand (UCalg)
Type spec mass (g):20.37
Type spec location:UWO
Main mass:R. Hamilton
Finder:R. Hamilton
Comments:Submitted by P. McCausland
Institutions
   and collections
UCalg: University of Calgary, Calgary, Alberta T2N 1N4, Canada (institutional address; updated 27 Feb 2011)
UWO: University of Western Ontario, Department of Earth Sciences, BGS 1026, 1151 Richmond St. N, London, Ontario, Canada N6A 5B7, Canada (institutional address; updated 18 Jul 2015)
Catalogs:
References: Published in Meteoritical Bulletin, no. 111, in preparation (2022)
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Photos:
CreditPhotos
Public domain photographs:
Phil McCausland         
Geography:

Canada
Coordinates:
     Recommended::   (51° 17' 43"N, 116° 57' 30"W)

Statistics:
     This is 1 of 4 approved meteorites from British Columbia, Canada (plus 2 unapproved names)
     This is 1 of 66 approved meteorites from Canada (plus 5 unapproved names) (plus 31 impact craters)
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