A United States Marine has been charged with assaulting a public servant, aged in her 60s, at the Enoggera Barracks army base in Brisbane's north-west.

The woman was allegedly dragged out of her car, assaulted by a man in a car park, and taken to hospital with serious injuries on Tuesday afternoon.

A 20-year-old man was arrested and charged by Queensland Police just after 3pm, reportedly with assistance from military police.

The man, a member of the United States Marine Corps, was charged with a serious assault in relation to a person over 60, wilful damage to the alleged victim's car and assaulting police.

Police said a male police officer who tried to intervene in the assault was allegedly himself assaulted.