Surface exposure dating with cos-mogenic nuclides

A bumper system has at least one element for absorbing impact energy by deflection in a direction generally parallel to the direction of the impact. The element has a terminal energy-absorption value beyond which additional energy is not absorbed and further deflection does not occur. The bumper system also includes a mounting support that is used to join the element to the object to be protected and that is capable of asymetrical energy-absorbing deformation so that, upon receipt by the bumper system of an impact having an energy value greater than the terminal energy-absorption value of the element and after full deflection of the element, the fully-deflected element is rotated through an angle of at least 90 DEG .