From my link above: "Research published in 2012 has shown that the so-called "black mats" are easily explained by typical earth processes in wetland environmen

From my link above: "Research published in 2012 has shown that the so-called "black mats" are easily explained by typical earth processes in wetland environments.[e][96] The study of black mats, that are common in prehistorical wetland deposits which represent shallow marshlands, that were from 6000 to 40,000 years ago in the southwestern USA and Atacama Desert in Chile, showed elevated concentrations of iridium and magnetic sediments, magnetic spherules and titanomagnetite grains. It was suggested that because these markers are found within or at the base of black mats, irrespective of age or location, they probably arise from processes common to wetland systems and not as a result of catastrophic bolide impacts" As for, "For the Chicxulub impact the black mat with impact proxies was the clincher that settled the hypothesis that an asteroid wiped out the dinos." the black mats in YDIH are completely distinct from the global KT boundary, not comparable. And the shocked quartz, crater rim, gravity anomaly, expected spherulite distribution around the world, and myriad other pieces of evidence at the Chicxulub site that lined up with the KT bound based on multiple time estimation techniques (as well as much, much better fit with observed extinction patterns in existing biota).