Over the past eleven years, the Mars Science Laboratory (MSL) rover Curiosity has been investigating the plains of Aeolis Palus and the lower reaches of Aeolis Mons (informally known as Mount Sharp), a 5 km tall mound of sedimentary rocks in Gale crater (Fig. 1). After traversing 31 km and about 800 m of vertical stratigraphy, three lithostratigraphic groups have been identified: Bradbury, Mount Sharp (Mt. Sharp), and Siccar Point (SP) (Fig. 1). The Bradbury group primarily consists of fluvial and lacustrine sedimentary rocks (e.g., [1-4]). The basal Murray formation of the Mt. Sharp group mainly corresponds to laminated mudstones with minor fluvial sandstones, interpreted as evidence of a long-lived lacustrine environment (e.g., [3, 5, 6]). At several localities along the traverse, exposures of the Mt. Sharp group are unconformably overlain by coarser-grained, aeolian cross-bedded sandstones of the Stimson formation (SP group), interpreted to have deposited on an aeolian deflation surface (e.g., [7-9]). While these three groups show evidence of deposition in specific environmental and climatic conditions, knowledge of their stratigraphic relationships is a key information to understand the evolution of environmental conditions in Gale. No clear stratigraphic contact has been observed neither at the boundary between the Bradbury and the Mt. Sharp groups, nor between the Bradbury and the SP groups. Because the mean dip of the Bradbury group is approximately horizontal, the MSL team suggested that the Bradbury group might be stratigraphically lower than the Mt. Sharp group, and therefore lower than the SP group [2]. Since then, analyses of chemical data from the APXS and ChemCam instrument suites have shown that rocks of the SP group exposed on Emerson Plateau, Naukluft Plateau and the Greenheugh pediment have similar chemical compositions to many of those of the Bradbury group [10-12]. The objective of this study is to reappraise the chemical compositions of the Bradbury and SP groups encountered by Curiosity in major localities by integrating data recently collected in the Marker Band Valley (upper Gediz Vallis Ridge floats) using ChemCam data. This approach could shed new light on sediment provenance, weathering and alteration conditions, and possible chemostratigraphic relationships between the Bradbury and SP groups.