Deposits - John Seach
of pyroclastic deposits
||Drape the landscape. Well sorted.
Deposited cool. Vertical trajectory.
||Do not evenly drape the landscape,
but pinch and swell. Vary from poor to well sorted. Transient high temperatures
such as burn victims or carbonised vegetation. Horizontal trajectory.
||Confined to valleys. Poorly sorted.
High temperation deposition indicated
by carbonised vegetation, thermal oxidation colours, and eruption welding.
surge is a turbulent cloud of gas and rock fragments that flows across
not constrained by topography but can move over obstacles such as ridges
There are 4 factors operating during
Trajectories of particles from vertical
Concentration of particles in the deposited
Fluctuation in deposition rate. Determines
degree of sorting.
Degree of cohesion. More cohesive means
longer lasting deposits.
Copyright John Seach