< p >第四纪绝对是一个好猜。但是很难回答你的问题,因为“一个峡湾的时代”是一个相当模糊的概念。同时,我会asume你感兴趣相关的基岩地形峡湾,不仅大海水湾(在这种情况下他们会形成最近,当冰川消退足以让海水取而代之)。说让我们试着回答这个问题:< / p > < p >海湾西部的巴塔哥尼亚是一个特性由更新世冰期,所以你可以肯定地说,海湾作为景观的一个特性是在第四纪期间形成的。然而,他们在不断进化,所以你也可以说说今天你看到他们的峡湾,形成今天。< / p > < p >在巴塔哥尼亚冰川侵蚀率范围大致从零点几毫米到几厘米。更快的利率可能发生在冰原的冰川的边缘基底滑动速度更高。长期平均水平(~ 10 ka)之间可能是< a href = " https://www.researchgate.net/publication/235711943_Timescale_dependence_of_glacial_erosion_rates_A_case_study_of_Marinelli_Glacier_Cordillera_Darwin_southern_Patagonia " rel = " nofollow noreferrer " > 0.5毫米/年< / >和< a href = " https://www.researchgate.net/publication/215614431_The_relative_efficacy_of_fluvial_and_glacial_erosion_over_modern_to_orogenic_timescales " rel = " nofollow noreferrer " > 1毫米/年< / >,这意味着2.6 Ma的第四纪你会侵蚀只是一到两公里。可以比这更深一些峡湾(当测量从山顶),很明显,峡湾的地理特征<强>不稳态< / >强,和他们现在比以往任何时候都更戏剧性的整个第四纪。< / p > < p > < a href = " https://i.stack.imgur.com/MRfST.png " rel = " nofollow noreferrer " > < img src = " https://i.stack.imgur.com/MRfST.png " alt = "在这里输入图像描述" > < / > < em >以出口在巴塔哥尼亚冰川侵蚀率在不同的时间尺度和其他领域。从图2所示。a in "The relative efficacy of fluvial and glacial erosion over modern to orogenic timescales" 2009, Nature Geoscience 2(9):644-647. The reason that explain why Fjords can become deeper than that one kilometer estimate, is the concentrated erosión in outlet glaciers at the edge of the ice sheet. For example, the most visited glacier in the Northern Patagonian Icefield: the San Rafael glacier, show erosion rates of 0.83 mm/year. And as shown in the figure above, outlet glaciers can erode up to ~5 cm/yr at shorter timescales.
Sumarizing:
Northern Patagonian Ice Field's fjords started to form with the first Pleistocene glaciation at the begin of the Quaternary about 2.6 million years ago, but they have become deeper after each successive glaciation and they are still forming today. Current glaciers are eroding their bedrock at rates on the order of one to a few centimeters per year.