当前位置: X-MOL 学术J. Geophys. Res. Planets › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Paleointensity and Rock Magnetism of Martian Nakhlite Meteorite Miller Range (MIL) 03346: Evidence for Intense Small Scale Crustal Magnetization on Mars
Journal of Geophysical Research: Planets ( IF 4.8 ) Pub Date : 2021-05-11 , DOI: 10.1029/2021je006856
Michael W. R. Volk 1 , Roger R. Fu 1 , Anna Mittelholz 2 , James M. D. Day 3
Affiliation  

The martian dynamo's strength and duration are essential for understanding Mars' habitability and deep interior dynamics. Although most northern volcanic terranes were likely emplaced after the martian dynamo ceased, recent data from the InSight mission show stronger than predicted crustal fields. Studying young volcanic martian meteorites offers a precise, complementary method to characterize the strength of the martian crustal field and examine its implications for past dynamo activity. We present the first rock and paleomagnetic study of nine mutually oriented samples from the martian Nakhlite meteorite MIL 03346, which is well‐suited for paleomagnetic analysis due to its well‐known age (1368 ± 83 Ma) and lack of significant aqueous, thermal, and shock overprinting. Rock magnetic analysis, including quantum diamond microscope (QDM) imaging, showed that the natural remanent magnetization (NRM) is carried by Ti‐magnetite crystals containing µm‐scale ilmenite exsolution lamellae, which can accurately record ancient magnetic fields. Demagnetization of the NRM revealed a high coercivity magnetization interpreted to date from the age of eruption based on its intensity, unidirectionality, and a passing fusion crust baked contact test. Paleointensities of four samples reveal a 5.1±1.5 µT paleofield, representing the most reliable martian paleointensity estimates to‐date and stronger than the 2 µT surface fields measured by InSight. Modeling shows that the observed fields can be explained by an older sub‐surface magnetized layer without a late, active dynamo and support a deeply buried, highly magnetized crust in the northern hemisphere of Mars. These results provide corroborating evidence for strong, small scale crustal fields on Mars.

中文翻译:

火星纳赫石陨石米勒山脉(MIL)03346的古强度和岩石磁性:火星上强小规模地壳磁化的证据

火星发电机的力量和持续时间对于理解火星的可居住性和深厚的内部动力至关重要。尽管大多数北部火山岩层可能在火星发电机停止运行后就位了,但InSight任务的最新数据显示其地壳强于预期。对年轻的火山火星陨石的研究提供了一种精确的补充方法来表征火星地壳场的强度,并研究其对过去发电机活动的影响。我们对火星的纳赫石陨石MIL 03346的9个相互定向的样本进行了首次岩石和古地磁研究,由于其已知的年龄(1368±83 Ma)且缺乏明显的水,热,热,热,热,热,热等因素,因此非常适合古磁分析。和令人震惊的叠印。岩石磁分析 包括量子金刚石显微镜(QDM)成像在内的数据表明,天然剩余磁化强度(NRM)是由含微米级钛铁矿浸出层的Ti-磁铁矿晶体携带的,该晶体可以准确记录古代磁场。NRM的退磁显示出高矫顽力的磁化强度,其强度,单向性和通过的熔壳烘烤测试通过可以解释为从喷发时代开始至今。四个样品的古强度揭示了5.1±1.5 µT的古场,代表了迄今为止最可靠的火星古强度估计,并且比InSight测量的2 µT表面场强。建模表明,观察到的磁场可以由较旧的地下磁化层解释,而没有较晚的活动发电机并支撑着深埋的,火星北半球的高度磁化地壳。这些结果为火星上强而小规模的地壳场提供了确凿的证据。
更新日期:2021-05-12
down
wechat
bug