Soil column (monolith) being prepared for removal at Arenosa Shelter. These samples allow geologists and soil scientists to study the site's sediments back in the laboratory. The collection process begins with the excavation of two parallel channels, leaving a narrow intervening sediment column. Boards are then used to create a 3-sided box to hold the column together. Finally, the column is carefully cut free of the wall and another board is used to cover the open side and finish the box. Properly prepared monoliths can be stored for decades as a near-permanent record of the site's stratigraphy. ANRA-NPS archives at TARL. |