"On the north coast of Peru, researchers have discovered the oldest adobe architecture in the Americas, constructed with ancient mud bricks carved from natural clay deposits created by floods caused by El Nino." Source: Archaeology News Network.
"The pre-Hispanic bricks — carved from sedimentary layers versus created by mixing clay, temper and water — date the invention of adobe architecture to more than 5,100 years ago, according to the international research team led by archaeologist Ana Cecilia Mauricio."