Scholarlink

<p>The calcareous tufas in this study occur in a large fan-shaped body at the terminus of the Oued (River) Bourkaïz, fed by the karstic Ain (Spring) Bourkaïz, in the arid Saïs Basin, near Fez, Morocco. These Mid-to-Upper Holocene tufas occur as nine facies distributed across three morpho-sedimentary units: barrages (dams, back-barrage pools, and distal-fan deposits. The facies include oncolitic, phytoclastic, stromatolitic, moss, phytohermal-stem, bioclastic gastropodal, melanized, microbial limestone, and sand tufa facies. SEM analysis indicates the relevant role of megaphytes, cyanobacteria, and algae in the calcite precipitation of these tufa facies. Carbon-isotope signatures suggest interaction with organic matter and CO<sub>2</sub> of biogenic origin, while oxygen-isotope signatures revealed various amounts of evaporation depending on the nature of the facies. Moreover, radiocarbon dating of the lowermost back barrage tufas (6.7–5.6&#xa0;cal.&#xa0;ka&#xa0;BP) suggests initial tufa formation during the wet, humid, Mid-Holocene African Humid Period, while the uppermost, back-barrage tufas show dates that range between 2.2 and 2.1&#xa0;cal&#xa0;ka&#xa0;BP, dates that approximately coinciding with the Roman-Iberian Climate Optimum.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Paleoclimatic implications and depositional settings of Mid to Upper Holocene calcareous tufas on the Bourkaïz tufa fan, Saïs Basin, northern Morocco

  • 期刊论文

  • 发表日期：

    2025年8月23日

查看全文
  • Ayman Agharabi,
  • Lahcen Gourari,
  • L’houcine Karrat,
  • Frank Robert Ettensohn,
  • Nicolae Har,
  • Constantin Balica,
  • Michael McGlue,
  • Cristian Victor Mircescu,
  • Horea Bedelean,
  • Alina Magdas

摘要

The calcareous tufas in this study occur in a large fan-shaped body at the terminus of the Oued (River) Bourkaïz, fed by the karstic Ain (Spring) Bourkaïz, in the arid Saïs Basin, near Fez, Morocco. These Mid-to-Upper Holocene tufas occur as nine facies distributed across three morpho-sedimentary units: barrages (dams, back-barrage pools, and distal-fan deposits. The facies include oncolitic, phytoclastic, stromatolitic, moss, phytohermal-stem, bioclastic gastropodal, melanized, microbial limestone, and sand tufa facies. SEM analysis indicates the relevant role of megaphytes, cyanobacteria, and algae in the calcite precipitation of these tufa facies. Carbon-isotope signatures suggest interaction with organic matter and CO2 of biogenic origin, while oxygen-isotope signatures revealed various amounts of evaporation depending on the nature of the facies. Moreover, radiocarbon dating of the lowermost back barrage tufas (6.7–5.6 cal. ka BP) suggests initial tufa formation during the wet, humid, Mid-Holocene African Humid Period, while the uppermost, back-barrage tufas show dates that range between 2.2 and 2.1 cal ka BP, dates that approximately coinciding with the Roman-Iberian Climate Optimum.