The ooze in question was sealed off by a bacteria-proof layer of chert-like material called porcellanite.
上述软泥被一种类似硅质岩的材料——瓷状岩——的隔菌层所封闭的。
英语百科
Porcellanite
Porcellanite or porcelanite, is a hard, dense rock somewhat similar in appearance to unglazed porcelain. It is often an impure variety of chert containing clay and calcareous matter.
At Tievebulliagh, Northern Ireland, porcellanite is a tough contact metamorphosed hornfels formed from a lateritic soil horizon within a basaltic intrusive/extrusive sequence. It is the site of a Neolithic axe or stone tool quarry.