I found Klaus Cornell’s "Oratrio Spelaeologio"
at the cult record shop, "art into life" in the ceramic city Mashiko, Japan.
There's few information about this artist on line and I can't judge the era. It's like the ruins made by sound.
#artintolife で見つけた、Klaus Cornellという音楽家のアルバム、そのまんま未来縄文篇のサウンドに使いたいくらい何時代かわからなくてカッコいい。音で出来た遺跡のよう。
https://www.art-into-life.com/phone/product/13828