Tagish Lake

British Columbia , Canada

Fell 2000 January 18, 08:43:42 pst (16:43:42 ut )

Carbonaceous chondrite (C2, ungrouped)

A brilliant fireball followed by loud detonations was widely observed over the Yukon Territory and northern British Columbia.  The fireball was also detected by satellites in Earth orbit.  Dust clouds from terminal fragmentation events were widely observed.  Jim Brook recovered several dozen meteorites totaling ~ 1 kg on the ice of Taku Arm, Tagish Lake, on January 25 and 26 (coordinates of first find given above).  Between April 20 and May 8, ~ 500 additional specimens were located on the ice of Taku Arm and a small, unnamed lake 1.5 km to the east, but only ~ 200 were retrieved as many had melted down into the ice making their collection time consuming; recovery was prioritized based on meteorites' mass and degree of disaggregation.  The total mass collected was between 5 and 10 kg.  The strewnfield is at least 16 × 3 km, oriented approximately S30° E.  Classification and mineralogy (M. Zolensky, JSC; M. Grady, NHM):  possibly CI2 group; a matrix-dominated chondrite, with a few small chondrules, CAIs, and isolated grains; matrix mainly phyllosilicates, Fe-Ni sulfides and magnetite, with abundant Ca-Mg-Fe carbonates; olivine, Fa_0–29, PMD = 2%, with a peak at Fa₁; pyroxene, Fs_1–7, PMD = 2%, with a peak at Fs₂; bulk C content 5.4 wt%, with δ¹³C = +24.3‰; shock stage, S1.  Oxygen isotopes (R. Clayton, UChi):  δ¹⁸O = +18.0 to 19.0‰, δ¹⁷O = 8.3 to 9.2‰.  Specimens:  majority held by UCalg (contact A. Hildebrand) and UWO (contact P. Brown).