Paris (CM) – micro_

$ 55.00

1 in stock

Description

Micro specimen

Sold in a box with label/certificate of authenticity


Paris 19°47.139’N, 55°51.21’E
Unknown location
Find: 2001
Carbonaceous chondrite (CM)

History: This sample was in an auction box lot bought by Jean-Jacques Corré at the Hotel des Ventes in Paris. The box was part of the estate of Jean Simon Colonna-Cimera, an “Ingénieur des Mines,” who supervised mines in foreign countries and in the French Colonies. Corré thought that the stone might be a meteorite but kept it for 7 years before attempting to have it identified.

Physical characteristics: One complete, fresh stone weighing 1.370 kg and covered with a very black fusion crust (Fig. 6).

Petrography: (M. Bourot-Denise, B. Zanda, MNHNP): The stone contains abundant metal and refractory inclusions up to 800 μm in size. The chondrules (up to 1 mm in size) are well preserved, although their mesostases are altered to phyllosilicates. The finegrained matrix is heterogeneous and contains zones with abundant sulfides (pyrrhotite and pentlandite), zones with magnetites, and zones with PCPs.

Geochemistry: Olivine (Fa0.2–55, CaO = 0.35, Cr2O3 = 0.35); low-Ca pyroxene (Fs0.6–4.4). Minor phases: kamacite (average: Ni = 5.5, Co = 0.22), tochilinite, pyrrhotite, pentlandite, magnetite (pure Fe3O4); calcite and PCPs (average: FeO = 52, SiO2 = 12, S = 9). (EPMA and expressed in wt%). Oxygen isotopes: δ18O=3.34‰, δ17O= -1.37‰.

Classification: Carbonaceous chondrite (CM), no signs of terrestrial weathering or shock (chondrules are perfectly spherical). Chondrules are more abundant and phyllosilicates less abundant than in CM2s. PCP averages 4.51 for FeO⁄SiO2 and 0.77 for S⁄SiO2, well out of the ranges defined by Rubin et al. (2007), making Paris significantly less aqueously altered than any known CM2. Oxygen isotopes also place it toward the least hydrated end of CM chondrites.

Specimens: The mass of 1.275 kg and one thin section are on deposit at MNHNP.