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Estimated Refractive Indices of Calcite, Dolomite, and Magnesite: ~0.3-500 M.Carbonate minerals are germane to questions involving volatile and climate history on Mars [e.g., 1-2]. In particular, the abundance of carbonate-bearing minerals can provide broad useful bounds on the amount of CO2 out-gassed into the atmosphere over its history and their spatial distribution and mineralogy can yield constraints on the environments in which they were produced. Earth-based, orbital, and landed spectral observations provide evidence for the presence of carbonates in the Martian environment [3-6]. Infrared observations made from spacecraft near Mars were interpreted to indicate the presence of carbonates. [6] associated the carbonates with the surface dust and interpreted the mineralogy as being consistent with magnesite (MgCO3). Near- infrared observations from Mars orbit have been interpreted to suggest magnesite outcrops in restricted locations [7-9]. Quantitative estimates of the abundance of carbonates on Mars range from 0-3% [3], 2-5% [6], less than a few percent [10], and <10% [8]. With the growing evidence for magnesite on Mars additional quantitative estimates can be provided via theoretical modeling of the reflectance from the Martian surface. Calcite (CaCO3) and dolomite ((Ca,Mg)CO3) are identified in Asian dust [2-17%], [10] and calcite in Saharan dust [~8-10% [12-15]. The importance of op- tical constants at visible and near-infrared wavelengths as proxies for estimating the effects at infrared wave- lengths, has been investigated [15]. The growing evidence for Mg-carbonates on Mars, the presence of calcite and dolomite in terrestrial aero- sols, and general lack of optical constants for these materials in the visible- to mid-infrared (VMIR, ~0.3-6 ❍m) has motivated the current effort to estimate the optical constants of calcite, dolomite, and magnesite in the VMIR.
Document ID
20190001826
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Roush, T. L. (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
March 25, 2019
Publication Date
March 21, 2019
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
ARC-E-DAA-TN65415
Meeting Information
Meeting: Lunar and Planetary Science Conference (LPSC)
Location: The Woodlands, TX
Country: United States
Start Date: March 18, 2019
End Date: March 22, 2019
Sponsors: Lunar and Planetary Institute (LPI)
Funding Number(s)
WBS: WBS 811073.02.37.01.65
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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