In late September, the typically docile Ear Spring geyser in Yellowstone National Park erupted with a forceful blast that shot up to 30 feet of water into the air. Amidst the debris that spewed out of the geyser during the eruption were not only rocks and dirt, but pieces of human-made trash—some of which dates back several decades.

Park officials discovered items like a cement block, aluminum cans, cigarette butts, a rubber heel insert, an 8-inch-long drinking straw, almost 100 coins and a baby pacifier from the 1930s, as Brandon Specktor reports for LiveScience.

"The water had just washed out under the boardwalk and had strewn trash all around," Rebecca Roland, a Yellowstone National Park supervisory park ranger, tells CBS News.

Ear Spring is located on Geyser Hill not far from Old Faithful, Yellowstone’s most famous thermal feature. According to the United States Geological Survey (USGS), Ear Spring experienced a small eruption as recently as 2004, but a blast as strong as the one that occurred last month has not been seen since 1957.

Since the eruption at Ear Spring, thermal features on Geyser Hill have been ramping up in activity, and the area of heated ground could continue to expand and change for several years. According to USGS, such shifts are “common occurrences” and are not connected to the activity of Yellowstone’s supervolcano, which shows no signs of erupting anytime soon.

“Shifts in hydrothermal systems occur only the upper few hundred feet of the Earth's crust,” USGS explains on their website, “and are not directly related to movement of magma several kilometers deep.”

Because some of the trash that recently flew out of Ear Spring is “clearly historic,” the items may be inventoried by curators and catalogued in Yellowstone’s archives, the park noted on Facebook. But that doesn’t mean Yellowstone visitors should feel free to continue chucking their garbage into geysers for posterity’s sake.

"You might think that if you toss something in a hot spring or in a geyser that it disappears, but it doesn't disappear,” Roland tells CBS. “It stays in that and what normally happens is you can actually plug up a feature and kill the feature. And that's happened in many places in the park.”

So, as Yellowstone says in its statement, the next time Ear Spring erupts, let’s hope “it's nothing but natural rocks and water.”