TY  - GEN
N2  - The Moon generated a long-lived core dynamo magnetic field, with intensities at least episodically reaching ~10­­–100 µT during the period prior to ~3.56 Ga.  While magnetic anomalies observed within impact basins are likely attributable to the presence of impactor-added metal, other anomalies such as those associated with lunar swirls are not as conclusively linked to exogenic materials. This has led to the hypothesis that some anomalies may be related to magmatic features such as dikes, sills, and laccoliths. However, basalts returned from the Apollo missions are magnetized too weakly to produce the required magnetization intensities (>0.5 A/m).  Here we test the hypothesis that subsolidus reduction of ilmenite within or adjacent to slowly cooled mafic intrusive bodies could locally enhance metallic FeNi contents within the lunar crust.  We find that reduction within hypabyssal dikes with high-Ti or low-Ti mare basalt compositions can produce sufficient FeNi grains to carry the minimum >0.5 A/m magnetization intensity inferred for swirls, especially if ambient fields are >10 μT or if fine-grained Fe-Ni metals in the pseudo-single domain grain size range are formed.  Therefore, it is plausible that the magnetic sources responsible for long sublinear swirls like Reiner Gamma and Airy may be magmatic in origin.  The results of this study will help guide interpretations of lunar crustal field data acquired by future rovers that will traverse lunar magnetic anomalies.
DO  - 10.7936/6rxs-103643
DO  - doi
AB  - The Moon generated a long-lived core dynamo magnetic field, with intensities at least episodically reaching ~10­­–100 µT during the period prior to ~3.56 Ga.  While magnetic anomalies observed within impact basins are likely attributable to the presence of impactor-added metal, other anomalies such as those associated with lunar swirls are not as conclusively linked to exogenic materials. This has led to the hypothesis that some anomalies may be related to magmatic features such as dikes, sills, and laccoliths. However, basalts returned from the Apollo missions are magnetized too weakly to produce the required magnetization intensities (>0.5 A/m).  Here we test the hypothesis that subsolidus reduction of ilmenite within or adjacent to slowly cooled mafic intrusive bodies could locally enhance metallic FeNi contents within the lunar crust.  We find that reduction within hypabyssal dikes with high-Ti or low-Ti mare basalt compositions can produce sufficient FeNi grains to carry the minimum >0.5 A/m magnetization intensity inferred for swirls, especially if ambient fields are >10 μT or if fine-grained Fe-Ni metals in the pseudo-single domain grain size range are formed.  Therefore, it is plausible that the magnetic sources responsible for long sublinear swirls like Reiner Gamma and Airy may be magmatic in origin.  The results of this study will help guide interpretations of lunar crustal field data acquired by future rovers that will traverse lunar magnetic anomalies.
AD  - Washington University in St. Louis
AD  - Stanford University
AD  - Washington University in St. Louis
T1  - Plausibility of lunar crustal magmatism producing strong crustal magnetism
ED  - Researcher
DA  - 2023-10-19
AU  - Liang, Yuanyuan
AU  - Tikoo, Sonia
AU  - Krawczynski, Michael
L1  - https://data.library.wustl.edu/record/103643/files/figures_and_tables.zip
L1  - https://data.library.wustl.edu/record/103643/files/RawEPMAData.zip
L1  - https://data.library.wustl.edu/record/103643/files/RawRockmagData.zip
L1  - https://data.library.wustl.edu/record/103643/files/readme_doi1079366rxs103643_Liang.txt
PB  - Washington University in St. Louis
LA  - eng
PY  - 2023-10-19
ID  - 103643
L4  - https://data.library.wustl.edu/record/103643/files/figures_and_tables.zip
L4  - https://data.library.wustl.edu/record/103643/files/RawEPMAData.zip
L4  - https://data.library.wustl.edu/record/103643/files/RawRockmagData.zip
L4  - https://data.library.wustl.edu/record/103643/files/readme_doi1079366rxs103643_Liang.txt
KW  - Earth and related environmental sciences
KW  - Ilmenite reduction experiments
KW  - lunar swirls
KW  - lunar magnetic anomalies
KW  - thermoremanent magnetization
TI  - Plausibility of lunar crustal magmatism producing strong crustal magnetism
Y1  - 2023-10-19
L2  - https://data.library.wustl.edu/record/103643/files/figures_and_tables.zip
L2  - https://data.library.wustl.edu/record/103643/files/RawEPMAData.zip
L2  - https://data.library.wustl.edu/record/103643/files/RawRockmagData.zip
L2  - https://data.library.wustl.edu/record/103643/files/readme_doi1079366rxs103643_Liang.txt
LK  - https://data.library.wustl.edu/record/103643/files/figures_and_tables.zip
LK  - https://data.library.wustl.edu/record/103643/files/RawEPMAData.zip
LK  - https://data.library.wustl.edu/record/103643/files/RawRockmagData.zip
LK  - https://data.library.wustl.edu/record/103643/files/readme_doi1079366rxs103643_Liang.txt
UR  - https://data.library.wustl.edu/record/103643/files/figures_and_tables.zip
UR  - https://data.library.wustl.edu/record/103643/files/RawEPMAData.zip
UR  - https://data.library.wustl.edu/record/103643/files/RawRockmagData.zip
UR  - https://data.library.wustl.edu/record/103643/files/readme_doi1079366rxs103643_Liang.txt
ER  -