Unprecedented long chain 1-chloroalkenes and 1-chloroalkanes in the Holocene sediments of Lake El Junco, Galápagos Islands

► We report long chain n-chloroalkanes and chloroalkenes in the recent sediments. ► Chloroalkanes and chloroalkenes have a chlorine atom at the terminal position. ► The cis and trans alkenyl chlorides have double bonds near mid-chain. ► Chloroalkenes and some alkenols, diols and/or hydroxy acids likely from algal origin.