Samuel Spevack partnered with Morrow for the continued analysis. The researchers are searching for deformities in the rocks, such as shocked quartz, that require the high-shock pressure of impacts in order to form.
"We've found a few grains that exhibit some features of shock, but there still needs to be other searching and peer reviewing," Samuel Spevack said.
David Kring is an expert on impact craters at the Lunar and Planetary Institute in Houston. He said the presentation at the conference was appropriate for this stage of the crater analysis, but more rock analysis is required "to confirm an impact origin."
"The reason that's important is [that] there are a lot of geologic processes that make circular structures," he added.
According to Bennett Spevack, if a space rock did crash into California's Central Valley, it would have created a 1,500-megaton explosion.
"This is not big enough to have wiped out the dinosaurs, but I guess it certainly would have made headlines if one this size would hit San Francisco," he said.
Scientists believe California's Central Valley was underwater at the time of the possible meteorite strike. If so, the impact may have also triggered a tsunami.
The proposed impact crater, called the Victoria Island structure, is being added to a database of suspected impacts. It joins the 0.8-mile (1.3-kilometer) Cowell structure to the north as California's only potential impact craters.
Neither structure is confirmed.
"If [the Victoria Island structure] can be proven, it'll be the first one in California," Bennett Spevack said.
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