Record Details

Record 1 of 1
Ar-40/Ar-39 Ages for Maskelynites and K-Rich Melt from Olivine-Rich Lithology in (Kanagawa) Zagami
NTRS Full-Text: Click to View  [PDF Size: 574 KB]
Author and Affiliation:
Park, J.(Lunar and Planetary Inst., Houston, TX, United States);
Herzog, G. F.(Rutgers Univ., Piscataway, NJ, United States);
Nyquist, L. E.(NASA Johnson Space Center, Houston, TX, United States);
Lindsay, F.(Rutgers Univ., Piscataway, NJ, United States);
Turrin, B.(Rutgers Univ., Piscataway, NJ, United States);
Swisher, C. C., III(Rutgers Univ., Piscataway, NJ, United States);
Delaney, J. S.(Rutgers Univ., Piscataway, NJ, United States);
Shih, C.-Y.(Jacobs Technologies Engineering Science Contract Group, Houston, TX, United States);
Niihara, T.(Lunar and Planetary Inst., Houston, TX, United States);
Misawa, K.(National Inst. of Polar Research, Tokyo, Japan)
Abstract: We report Ar/Ar release patterns for small maskelynite grains and samples of a K-rich phase separated from the basaltic shergottite Zagami. The purpose of the work is to investigate the well-known discrepancy between published Ar/Ar ages of Zagami, >200 Ma, and its age of approx. 170 Ma as determined by other methods [1-6]. Niihara et al. [7] divide less abundant darker material present in Zagami into an olivine-rich lithology (ORL), from which most of our samples came, and a pyroxene-rich one (Dark Mottled-Lithology: DML) [8, 9]. ORL consists of vermicular fayalitic olivine, coarse-grained pyroxene, maskelynite, and a glassy phase exceptionally rich in K (up to 8.5 wt%), Al, and Si, but poor in Fe and Mg. The elemental composition suggests a late-stage melt, i.e., residual material that solidified late in a fractional crystallization sequence. Below we refer to it as "K-rich melt." The K-rich melt contains laths of captured olivine, Ca-rich pyroxene, plagioclase, and opaques. It seemed to offer an especially promising target for Ar-40/Ar-39 dating.
Publication Date: Mar 18, 2013
Document ID:
20130011089
(Acquired Mar 16, 2013)
Subject Category: GEOPHYSICS
Report/Patent Number: JSC-CN-27985
Document Type: Conference Paper
Meeting Information: Lunar aud Plauetary Science Conference; 18-22 Mar. 2013; The Woodlands, TX; United States
Financial Sponsor: NASA Johnson Space Center; Houston, TX, United States
Organization Source: NASA Johnson Space Center; Houston, TX, United States
Description: 2p; In English; Original contains color illustrations
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Distribution as joint owner in the copyright
NASA Terms: ACHONDRITES; BASALT; CHEMICAL COMPOSITION; CRYSTALLIZATION; LITHOLOGY; OLIVINE; PLAGIOCLASE; PYROXENES; SHERGOTTITES
› Back to Top
Facebook icon, External Link to NASA STI page on Facebook Twitter icon, External Link to NASA STI on Twitter YouTube icon, External Link to NASA STI Channel on YouTube RSS icon, External Link to New NASA STI RSS Feed
Find Similar Records
 
NASA Logo, External Link

NASA Official: Gerald Steeman
Sponsored By: NASA Scientific and Technical Information Program
Site Curator: STI Support Services
Last Modified: April 09, 2013

Privacy Policy & Important Notices Disclaimers, Copyright, Terms of Use Freedom of Information Act USA.gov NASA.gov NASA OCIO Free Adobe PDF Reader Free MS Word Viewer