Geological Map of Oxfordshire

A'a lava

a basaltic lava characterized by a rough or rubbly surface composed of broken lava blocks called clinker

A-horizon

The uppermost layer of a soil, containing organic material and leached minerals.

abyssal plain

The ocean floor offshore from the continental margin, usually very flat with a slight slope.

accrete

To add terranes (small land masses or pieces of crust) to another, usually larger, land mass.

accrete

To add terranes (small land masses or pieces of crust) to another, usually larger, land mass.

aeolian process

Geological modifications caused by wind activity e.g. erosion or deposition. Derived from Aeolus, the Greek God of wind.