Folsom Drought and Episodic Drying on the Southern High Plains from 10,900–10,200 14C yr B.P
Folsom Drought and Episodic Drying on the Southern High Plains from 10,900–10,200 14C yr B.P
复制标题
14C yr B.P. 10,900–10,200 期间福尔瑟姆干旱和南部高原的间歇性干燥
DOI：
10.1006/qres.1999.2089
复制
发表时间：
2000
影响因子：
2.3
通讯作者：
V. Holliday
中科院分区：
文献类型：
--
作者：
V. Holliday
南方高原晚更新世和全新世早期的古环境研究已有几十年的历史，但很难找到区域性的或长期的、易于恢复的代用气候指标。山谷填充物和高地风成沉积物的地层学和稳定碳同位素数据，以及地理上有限的古生物学数据，现在为这段时间的环境提供了线索，其中包括最早的古印度时期（11，200 -8000 14 C yr B. P.）人类的占领。在克洛维斯占领期间（11，200 - 10，900 14 C yr B. P.），山谷中有常年的溪流。福尔松时期（10，900 - 10，200 ~（14）C年B. P.）由于湖泊和池塘（水位在几米深之间波动，没有地表水）和沼泽的突然变化，以及高地上席状砂的堆积，开始了区域沙丘场建设的最早阶段。这些不断变化的条件表明，从相对潮湿到相对干燥的条件与间歇性干旱的转变。稳定碳同位素进一步表明，气候变暖是克洛维斯-福尔松转变的特征。在其余的古印度时期的环境是相对凉爽，但波动之间的潮湿和干燥的条件与整体趋势走向干燥，导致进一步扩大的沙丘领域，并最终在温暖，干燥的高温热开始8000年14 C B. P.克洛维斯时间可能是最潮湿的任何古印度时期的径流和泉水流量。福尔松时期较为干燥，是区域风蚀和风成沉积的最早期，可能是古印度时期最温暖的时期。以前假设的“克洛维斯干旱”在这一地区的证据很少。
Abstract The paleoenvironments of late Pleistocene and early Holocene time on the Southern High Plains have been studied for decades, but regionally extensive or long-term, easily recoverable proxy climate indicators are difficult to find. The stratigraphy of valley fill and upland eolian deposits and stable-carbon isotope data, in addition to geographically limited paleontological data, now provide clues to the environment during this time, which includes the earliest, or Paleoindian period (∼11,200–8000 14C yr B.P.) of human occupation. During the Clovis occupation (∼11,200–10,900 14C yr B.P.), valleys contained perennial streams. This was followed in Folsom time (10,900–10,200 14C yr B.P.) by an abrupt change to lakes and ponds (with water levels fluctuating between several meters depth and no surface water) and marshes and accumulation of sheet sands on uplands, starting the earliest phase of construction of the regional dune fields. These changing conditions indicate a shift from relatively wetter to relatively drier conditions with episodic drought. Stable-C isotopes further indicate that warming characterized the Clovis–Folsom transition. During the rest of the Paleoindian period the environment was relatively cool but fluctuated between wetter and drier conditions with an overall trend toward drying that resulted in further enlargement of the dune fields and culminated in the warm, dry Altithermal beginning ∼8000 14C yr B.P. Clovis time probably was the wettest of any Paleoindian period in terms of runoff and spring discharge. The Folsom period was drier and was the earliest episode of regional wind erosion and eolian deposition and may have been the warmest of Paleoindian times. Evidence of a previously hypothesized “Clovis drought” in this region is sparse.