The formation mechanism of dark spots on Mercury

Principal Investigator: Dr.Prof. Xiao Zhiyong

Period：2018.01- 2012.12

Project funding amount：RMB 690, 000

Project Description:

Dark spots on Mercury are a newly found geological unit, but their formation mechanism is still unknown. Dark spots have recorded important information about the origin and evolution of Mercury. Dark spots are small surface units that have the lowest reflectance on Mercury, and the reflectance spectra exhibit a shallow absorption feature at the 500–600 nm wavelengths. Most of the observed dark spots are located on areas that have relatively low reflectance compared with the global average. Some dark spots are extremely young, and each dark spot has an associated bright-haloed hollows. However, due to limited data coverage and resolution in previous studies, the formation mechanism of dark spots is still unknown. This proposal is determined to use the high-resolution image, reflectance spectra, and altimeter data to study the global distribution pattern, detailed morphology, geometry, reflectance spectra, age and geological background of dark spots. Using high-precision pixel registration technique, possible changes of dark spots will be studied; phase ratio analyses will be performed to study the relative particle sizes of dark spots and other mercurian clasts. Combined with the spatial relationship of dark spots and other geological units (such as bright-haloed hollows) on Mercury, the final target of this proposal is to study the formation mechanism of Mercury. This study will provide new perspective for studying possible causes for the low reflectance on Mercury and the activity of volatiles in the shallow crust of Mercury.