Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK.
Cryosphere Research at Manchester, Manchester, UK.
Nat Commun. 2022 Sep 21;13(1):5526. doi: 10.1038/s41467-022-33310-z.
The Antarctic continent reached its current polar location 83 Ma and became shrouded by ice sheets ~34 Ma, coincident with dramatic global cooling at the Eocene-Oligocene boundary. However, it is not known whether the first Antarctic glaciers formed immediately prior to this or were present significantly earlier. Here we show that mountain glaciers were likely present in the Transantarctic Mountains during the Late Palaeocene (60-56 Ma) and middle Eocene (48-40 Ma). Temperate (warm-based) glaciers were prevalent during the Late Eocene (40-34 Ma) and, in reduced numbers, during the Oligocene (34-23 Ma), before larger, likely cold-based, ice masses (including ice sheets) dominated. Some temperate mountain glaciers were present during the Miocene Climatic Optimum (15 Ma), before a widespread switch to cold-based glaciation. Our findings highlight the longevity of glaciation in Antarctica and suggest that glaciers were present even during the Early-Cenozoic greenhouse world.
南极大陆在 8300 万年前到达了现在的极区位置，并在 3400 万年前被冰盖覆盖，与始新世-渐新世之交的全球急剧降温同时发生。然而，目前尚不清楚第一批南极冰川是否在这之前立即形成，或者是否更早存在。在这里，我们表明在晚古新世（约 60-56 百万年前）和中始新世（约 48-40 百万年前），横贯南极山脉可能已经存在山岳冰川。在晚始新世（约 40-34 百万年前），温带（暖基）冰川盛行，数量减少，在渐新世（约 34-23 百万年前），更大量的、可能是冷基的冰体（包括冰盖）占主导地位。一些温带山地冰川存在于中新世气候最优期（约 1500 万年前），之后广泛转向冷基冰川作用。我们的发现强调了南极洲冰川作用的长久性，并表明即使在新生代温室世界冰川也存在。
