560fd65f_KS3_Ex___Earth_Science_On_Site__uitable_questions_at_this_site
[Acceptable responses] The fragments (pebbles) are mainly metamorphic with some granite. There are many angular and sub angular fragments (maybe 60% or more) with the rest being mainly sub rounded or rounded. (Very few, if any, are well rounded). The longest pebbles will exceed 64mm, indicating deposition in a minimum velocity of well over 300 cm per second. i.e. they were brought down at a time of very high stream flow.
Use step 2. worksheet 5. Form the group into parties of about 3 or 4, and allocate them a position along the stream. Ask them to select 20 of the largest fragments and decide on the angularity / rounding and the size of the largest fragment (longest axis). What does this evidence tell us about the formation of this sediment?
MEL/KS3/Ex - Earth Science On-Site
Suitable questions at this site