a soft porous rock consisting of calcium carbonate deposited from springs rich in lime
hard volcanic rock composed of compacted volcanic ash
造句
用作名詞(n.)
Mono Lake\\\'s tufa are particularly dramatic because water diversions have significantly lowered the lake\\\'s level, exposing more of the columns. 因?yàn)樗吹姆至魇购伙@著下降，使大多數(shù)泉華柱暴露出水面，瑪洛湖的泉華非常引人注目。
The reserve was established to preserve the spectacular tufa towers. 該自然保護(hù)區(qū)是為了保護(hù)湖區(qū)內(nèi)的“石灰塔”地貌而設(shè)。