It revealed the remains of a 454-year-old Spanish fort on an island off the coast of the Gulf of Florida.
The fortress is known as San Anton de Carlos, a 16th-century Spanish colony that contains the site of one of the first missionaries in North America.
It was built by the Spaniards in 1566 in the capital of a powerful Native American kingdom controlled by the people of Calusa. Today, the site is known as Mound Key, an island in Estero Bay.
Historical Spanish documents indicate that the capital of Calosa and Fort Sant Anton de Carlos were in the Mound Key. However, there was no evidence of its existence until archaeologists used the laser technique known as lidar (light and range detection) and ground penetration radar to find the remains of the fort.
William Marquardt, honorary curator of archeology and ethnography at the Florida Museum of Natural History in South Florida, said in a statement: “Archaeologists and historians visited the site and collected pottery from the roof, and even when we found material evidence of the home of King Calusa and the fortress, we were not quite sure.
The lidar technology helped to map the site with a laser, which gave archaeologists a detailed account of the site’s geography and structures. Likewise, the ground-penetrating radar revealed the exact location of the buried structures.
When the team excavated the site, they found the remains of the fort as well as ceramic pieces and beads.
They found that the fort is the oldest known example of “striped and dotted dark-colored” architecture in North America, which means that its walls were made of concrete veneer.
The researchers said that this substance is made when lime mixes from the shells burned with sand, ash, water and broken shells.
The researchers said that the Spaniards used this primitive geometry in the Mound Key, and used it as mortar to anchor the stanchions in the walls of their wooden structures and then repeated that English in American colonies, including southern plantations.
However, much work remains to be done before digging the entire fort. The team plans to continue their work, until the entire site is explored, as archaeologists have discovered only part of the fort, they said