{"id":290211,"date":"2025-04-25T14:36:48","date_gmt":"2025-04-25T14:36:48","guid":{"rendered":"https:\/\/news.talkwithrattan.com\/index.php\/2025\/04\/25\/the-united-states-oldest-known-rock-has-existed-for-at-least-3-6-billion-years\/"},"modified":"2025-04-25T14:36:48","modified_gmt":"2025-04-25T14:36:48","slug":"the-united-states-oldest-known-rock-has-existed-for-at-least-3-6-billion-years","status":"publish","type":"post","link":"https:\/\/news.talkwithrattan.com\/index.php\/2025\/04\/25\/the-united-states-oldest-known-rock-has-existed-for-at-least-3-6-billion-years\/","title":{"rendered":"The United States\u2019 oldest known rock has existed for at least 3.6 billion years"},"content":{"rendered":"
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A weathered sign in the Minnesota River Valley proudly proclaims: \u201cWorld\u2019s Oldest Rock.\u201d Erected in 1975, it marks a 3.8-billion-year-old gneiss \u2014 or so scientists thought.<\/p>\n\n\n\n

Turns out, it\u2019s not the world\u2019s oldest rock (Since 2019, that title has been held by an estimated 4-billion-year-old Canadian Acasta Gneiss). An analysis of minerals in the Minnesota gneiss and gneisses from across the country indicate that it\u2019s probably not even the oldest in the United States, geologist Carol Frost and colleagues report in the March-April GSA Today<\/em>. The age proclaimed on the sign may be overstated by at least 300 million years, the team argues. Instead, the old sign should be uprooted, revised to \u201cAmerica\u2019s Oldest Rock\u201d and hammered into Michigan\u2019s Watersmeet Gneiss<\/a>, which the researchers estimate is at least 3.6 billion years old.<\/p>\n\n\n