Holocene dune activity and environmental change in the prairie parki and and boreal forest, central Saskatchewan, Canada
Holocene dune activity and environmental change in the prairie parki and and boreal forest, central Saskatchewan, Canada
复制标题
加拿大萨斯喀彻温省中部草原公园和北方森林的全新世沙丘活动和环境变化
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
O. Lian
中科院分区：
文献类型：
--
作者：
S. Wolfe;J. Ollerhead;D. J. Huntley;O. Lian
过去的风沙活动重建在四个沙丘在萨斯喀彻温省中部的草原帕克兰和北方森林，以阐明景观对环境变化的响应。光学年龄从稳定的沙丘在北方过渡生态区表明两集的活动。第一，在约11万年，相当于一个时期的早全新世帕克兰和草地覆盖后约13.0万年的冰川消退和排水，并简要建立北方森林。第二，约7.5和5万年之间，相当于一个时期的中期全新世公园草地覆盖。从沙丘在草原帕克兰的光学年龄主要记录中全新世活动，约7.5和4.7万年之间，对应于一个时期的草原覆盖，与一些改造持续到晚全新世。虽然这一地区约13.5 ka的冰川消退，没有证据表明早全新世沙丘活动，这表明中全新世活动可能已经在这里改造早期沉积物。因此，在这些沙丘中观察到的大部分形态和地层与中全新世活动有关，可能与当时干旱增加和植被覆盖减少有关。这项研究提供了大平原上中全新世沙丘再活化的最北证据，支持当时广泛存在风成活动的说法。
Past aeolian activity was reconstructed at four dunefields in the prairie parkland and boreal forest of central Saskatchewan to elucidate landscape response to environmental change. Optical ages from stabilized dunes in the boreal transition ecoregion indicate two episodes of activity. The first, at about 11 ka, corresponds to a period of early-Holocene parkland and grassland cover following deglaciation and drainage after about 13.0 ka, and brief establishment of boreal forest. The second, between about 7.5 and 5 ka, corresponds to a period of mid-Holocene parkland-grassland cover. Optical ages from dunefields in the prairie parkland primarily record mid-Holocene activity, between about 7.5 and 4.7 ka, corresponding to a period of grassland cover, with some reworking continuing into the late Holocene. Although this area was deglaciated by about 13.5 ka, there is no evidence of early-Holocene dune activity, suggesting that mid-Holocene activity may have reworked earlier deposits here. Consequently, much of the morphology and stratigraphy observed in these dunefields are associated with mid-Holocene activity, likely associated with increased aridity and reduced vegetation cover at that time. This study provides the most northerly evidence of mid-Holocene dune reactivation on the Great Plains, lending support to the assertion that aeolian activity was widespread at that time.