Physical and compositional properties of impact melts for Jackson and Tycho craters: Implications for space weathering and degradation of lunar impact melts

Icarus ◽  
2020 ◽  
Vol 351 ◽  
pp. 113926
Author(s):  
M. Lemelin ◽  
S.T. Crites ◽  
M. Ohtake ◽  
P.G. Lucey ◽  
J. Haruyama ◽  
...  
2012 ◽  
Vol 117 (E12) ◽  
pp. n/a-n/a ◽  
Author(s):  
Lynn M. Carter ◽  
Catherine D. Neish ◽  
D. B. J. Bussey ◽  
Paul D. Spudis ◽  
G. Wesley Patterson ◽  
...  
Keyword(s):  

1975 ◽  
Vol 2 (9) ◽  
pp. 369-372 ◽  
Author(s):  
K. Keil ◽  
R. D. Warner ◽  
M. Prinz ◽  
E. Dowty
Keyword(s):  

2002 ◽  
Vol 202 (2) ◽  
pp. 217-228 ◽  
Author(s):  
Marc D. Norman ◽  
Vickie C. Bennett ◽  
Graham Ryder
Keyword(s):  

2015 ◽  
Vol 1 (1) ◽  
pp. e1400050 ◽  
Author(s):  
Cameron M. Mercer ◽  
Kelsey E. Young ◽  
John R. Weirich ◽  
Kip V. Hodges ◽  
Bradley L. Jolliff ◽  
...  

Quantitative constraints on the ages of melt-forming impact events on the Moon are based primarily on isotope geochronology of returned samples. However, interpreting the results of such studies can often be difficult because the provenance region of any sample returned from the lunar surface may have experienced multiple impact events over the course of billions of years of bombardment. We illustrate this problem with new laser microprobe 40Ar/39Ar data for two Apollo 17 impact melt breccias. Whereas one sample yields a straightforward result, indicating a single melt-forming event at ca. 3.83 Ga, data from the other sample document multiple impact melt–forming events between ca. 3.81 Ga and at least as young as ca. 3.27 Ga. Notably, published zircon U/Pb data indicate the existence of even older melt products in the same sample. The revelation of multiple impact events through 40Ar/39Ar geochronology is likely not to have been possible using standard incremental heating methods alone, demonstrating the complementarity of the laser microprobe technique. Evidence for 3.83 Ga to 3.81 Ga melt components in these samples reinforces emerging interpretations that Apollo 17 impact breccia samples include a significant component of ejecta from the Imbrium basin impact. Collectively, our results underscore the need to quantitatively resolve the ages of different melt generations from multiple samples to improve our current understanding of the lunar impact record, and to establish the absolute ages of important impact structures encountered during future exploration missions in the inner Solar System.


2019 ◽  
Author(s):  
Sarah E. Roberts ◽  
◽  
Molly C. McCanta ◽  
M. Darby Dyar ◽  
Cai Ytsma

Author(s):  
Ash Asudeh ◽  
Gianluca Giorgolo

This book presents a theory of enriched meanings for natural language interpretation. Certain expressions that exhibit complex effects at the semantics/pragmatics boundary live in an enriched meaning space while others live in a more basic meaning space. These basic meanings are mapped to enriched meanings just when required compositionally, which avoids generalizing meanings to the worst case. The theory is captured formally using monads, a concept from category theory. Monads are also prominent in functional programming and have been successfully used in the semantics of programming languages to characterize certain classes of computation. They are used here to model certain challenging linguistic computations at the semantics/pragmatics boundary. Part I presents some background on the semantics/pragmatics boundary, informally presents the theory of enriched meanings, reviews the linguistic phenomena of interest, and provides the necessary background on category theory and monads. Part II provides novel compositional analyses of the following phenomena: conventional implicature, substitution puzzles, and conjunction fallacies. Part III explores the prospects of combining monads, with particular reference to these three cases. The authors show that the compositional properties of monads model linguistic intuitions about these cases particularly well. The book is an interdisciplinary contribution to Cognitive Science: These phenomena cross not just the boundary between semantics and pragmatics, but also disciplinary boundaries between Linguistics, Philosophy and Psychology, three of the major branches of Cognitive Science, and are here analyzed with techniques that are prominent in Computer Science, a fourth major branch. A number of exercises are provided to aid understanding, as well as a set of computational tools (available at the book's website), which also allow readers to develop their own analyses of enriched meanings.


2021 ◽  
Vol 27 (S1) ◽  
pp. 2260-2262
Author(s):  
Alexander Kling ◽  
Michelle Thompson ◽  
Jennika Greer ◽  
Philipp Heck

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