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Selective sampling of asteroids, the Moon, and Mars: Factors affecting the numerical abundances of members of meteorite groups

Year: 2025
Type: article
Abstract: Meteorite collection inventories show that many related meteorite groups have very different numerical abundances (e.g., lunar versus Martian meteorites; Eagle Station pallasites versus main‐group pallasites; eucrites versus diogenites; ungrouped Antarctic irons versus ungrouped non‐Antarctic irons; carbonaceous chondrite‐related (CC) iron meteorites versus noncarbonaceous chondrite‐related (NC) iron meteorites). The number of members of individual meteorite groups reflects the entire history of these rocks from excavation on their parent bodies to recovery on Earth. These numbers are functions of six main selection factors: (1) volume of the parent‐body source region, (2) depth of this source region, (3) time spent in interplanetary space, (4) friability of meteoroids in space and during transit through the Earth's atmosphere, (5) susceptibility of meteorite finds to terrestrial weathering, and (6) post‐fall biases resulting from geography, demography, and preferences by meteorite collectors and analysts. The numerical ratio of lunar/Martian meteorites (~1.8) results from several factors including the Moon's proximity, the short transit time of lunar meteoroids through interplanetary space, the lower crustal depth from which lunar meteorites were excavated, the lower energy required to launch samples off the Moon than off Mars, and the lower porosity and higher mechanical strength of lunar meteorites. The dunite shortage among asteroidal meteorites may have resulted from the deeply buried olivine‐rich meteoroids being ejected hundreds of millions of years ago at the same time as pallasites and irons; however, the dunitic meteoroids (with their lower mechanical strength) would have eroded in interplanetary space on much shorter time scales than their metal‐rich fellow travelers.
DOI: 10.1111/maps.14367
Language: English
Open Access status: hybrid
Estimated APC paid: $3,300
Award: WE PROPOSE TO CONDUCT A SERIES OF INVESTIGATIONS OF THE MINERALOGIC COMPONENTS OF CHONDRITIC METEORITES THAT ARE THOUGHT TO HAVE FORMED ON PLANETESIMALS WITH THE GOAL OF DEVELOPING IMPROVED CHRONOLOGICAL CONSTRAINTS ON THEIR FORMATION AND ON THE OVERALL AQUEOUS EVOLUTION ON ASTEROIDS. OUR ANALYSES ARE DIRECTED TOWARD DEVELOPING A BETTER UNDERSTAND OF THE SEQUENCE AND TIMING OF MAJOR EVENTSIN PLANETARY ACCRETION AND DIFFERENTIATION WHICH IS DIRECTLY RELEVANT TO THE GOALS OF THE EMERGING WORLDS SOLICITATION TO UNDERSTAND THE FORMATION AND EARLY EVOLUTION OF THE SOLAR SYSTEM AND THE STRATEGIC QUESTION OF LEARNING HOW DID THE SUNS FAMILY OF PLANETS SATELLITES AND MINOR BODIES FORM AND EVOLVE?WE WILL UTILIZE CHRONOLOGICAL TOOLS THAT WE AND OTHERS HAVE PREVIOUSLY DEVELOPED IN A COORDINATED APPROACH UTILIZING PETROGRAPHY CHEMISTRY AND IN SITU ISOTOPIC ANALYSES. TIMESCALES OF EARLY GEOLOGIC ACTIVITY ON ASTEROIDAL PARENT BODIES OF METEORITES WILL BE ADDRESSED BY COUPLED ANALYSES OF THE MN-CR O-ISOTOPE AND C-ISOTOPE SYSTEMS IN CARBONATES AND OTHER SECONDARY MINERALS OF CARBONACEOUS CHONDRITES. PREVIOUS DATA SHOW THAT DIFFERENT CARBONATE MINERALOGIES IN CI CHONDRITES HAVE DISTINCT OXYGEN AND CARBON ISOTOPIC COMPOSITIONS SUGGESTING AN EVOLUTION OF FLUID COMPOSITIONS ON THE CI PARENT BODY. WE HAVE DEVELOPED A METHOD TO IMPROVE THE ACCURACY OF MN-CR DATING OF CARBONATES AND WE PROPOSE TO USE THE NEWEST GENERATION ION MICROPROBE AT UCLA TO DELINEATE THE FULL RANGE AND TIMING OF FLUID EVOLUTION ON THE PARENT ASTEROIDS OF CI AND OTHER SELECT CARBONACEOUS CHONDRITES. WE ALSO PROPOSE TO FOLLOW UP INTRIGUING HINTS OF 60FE ACTIVITY IN EARLY-FORMED CARBONATES VIA SIMS ANALYSES AND RESONANT IONIZATION MASS SPECTROMETRY (RIMS) ANALYSES WITH OUR COLLABORATOR ANDY DAVIS AT THE UNIVERSITY OF CHICAGO. AL-MG AND FE-NI SYSTEMATICS WILL BE MEASURED IN SELECT CHONDRULES FROM UNEQUILIBRATED CHONDRITES BY BOTH SIMS AND RIMS TO BETTER UNDERSTAND THE ABUNDANCE AND DISTRIBUTION OF 60FE IN THE EARLY SOLAR SYSTEM.A PLANETARY MAJOR EQUIPMENT REQUEST IS MADE FOR PURCHASE OF A MULTI-SAMPLE INTRODUCTION SYSTEM FOR OUR NEW CAMECA IMS 1290 ION MICROPROBE. THE IMS 1290 IS THE PRIMARY INSTRUMENT FOR THE RESEARCH PROPOSED HERE AND IT SERVES OTHER FUNDED AND PROPOSED NASA PROJECTS AS WELL PROJECTS BROUGHT TO THE NSF NATIONAL ION MICROPROBE FACILITY. THE INSTRUMENT WAS PURCHASED WITH SUBSTANTIAL ($4M) SUPPORT FROM THE NSF MAJOR RESEARCH INSTRUMENTATION PROGRAM NEVERTHELESS WE COULD ONLY AFFORD TO OUTFIT WITH THE MOST BASIC SINGLE-SAMPLE INTRODUCTION SYSTEM. THE NEW SYSTEM WILL ALLOW THE STORAGE OF UP TO SIX SAMPLES IN THE VACUUM ANTECHAMBER ADJACENTTO THE ANALYSIS CHAMBER. THIS WILL ENABLE IMPROVEMENTS IN BACKGROUND LEVELS OF VOLATILE ELEMENTS AND WILL THEREFORE LEAD TO HIGHER RELIABILITY AND HIGHER EFFICIENCY OF ANALYSES INCLUDING THE OXYGEN AND CARBON ISOTOPE MEASUREMENTS PROPOSED HERE.
OpenAlex ID: W4410602745
FWCI: 0.452
Cites: 160
Cited by: 1
Related to: 10