Late Jurassic clay mineral suites of the Annero Formation, Southern Sweden

Abstract

Two Late Jurassic successions from western Skåne were investigated with respect to clay mineral contents of mudstones. Although these resemble clay mineral suites from a third succession in Central Skåne, it is evident that different depositional areas show separate clay mineral trends with time, probably due to that detrital clay minerals were derived locally from heterogeneous weathered crystalline basement (smectite and kaolinite dominated) and from reworking of Palaeozoic shales (illite and chlorite dominated). Kaolinite is enriched in silty and sandy strata, probably due to sedimentary sorting processes and authigenic precipitation.

Keywords:

• Jurassic
• clay minerals
• stratigraphy
• Sweden