EaES 350-6 Contents Introduction Unconsolidated clastic sediments Sedimentary rocks Diagenesis Sediment transport an EaES 350-6 2021/4/14 星期三 12 EaES 350-6 2021/4/14 星期三 13 EaES 350-6 2021/4/14 星期三 14 EaES 350-6 2021/4/14 星期三 15 EaES 350-6 2021/4/14 星期三 16 EaES 350-6 2021/4/14 星期三 17 EaES 350-6 2021/4/14 星期三 18 EaES 350-6 Sedimentary structures Cross stratification The angle of climb of cross-stratified deposits increases with deposition rate, resulting in ‘climbing ripple cross lamination’ Antidunes form cross strata that dip upstream, but these are not commonly preserved A single unit of cross-stratified material is known as a set; a succession of sets forms a co-set 2021/4/14 星期三 19 EaES 350-6 2021/4/14 星期三 20 EaES 350-6 Sedimentary structures Planar stratification Planar lamination (or planar bedding) is formed under both lower-stage and upper-stage flow conditions Planar stratification can easily be confused with planar cross stratification, depending on the orientation of a section (strike sections!) 2021/4/14 星期三 21 EaES 350-6 2021/4/14 星期三 22 EaES 350-6 2021/4/14 星期三 23 EaES 350-6 2021/4/14 星期三 24 EaES 350-6 2021/4/14 星期三 25 EaES 350-6 Sedimentary structures Cross stratification produced by wave ripples can be distinguished from current ripples by their symmetry and by laminae dipping in two directions Hummocky cross stratification (HCS) forms during storm events with combined wave and current activity in shallow seas (below the fair-weather wave base), and is the result of aggradation of mounds and swales Heterolithic stratification is characterized by alternating sand and mud laminae or beds Flaser bedding is dominated by sand with isolated, thin mud drapes Lenticular bedding is mud-dominated with isolated ripples 2021/4/14 星期三 26 EaES 350-6 2021/4/14 星期三 27 EaES 350-6 2021/4/14 星期三 28 EaES 350-6 2021/4/14 星期三 29 EaES 350-6 Sedimentary structures Cro
