Abstract The interactive effects of paleoclimates and current conditions on pedogenesis in soils developed on volcanic parent materials (VPMs) is still poorly understood, particularly for soils in dry environments. Eight representative profiles located at Harrat Khaybar, Saudi Arabia and representing different landforms and positions including alluvial plain, alluvial fans, active slopes and lava field were investigated to better understand the effect of climate and basalt lithology on pedogenesis. The morphological and physicochemical soil properties and clay mineralogy composition were evaluated to identify the primary diagnostic horizons and therefore the pedogenic pathways that created the studied soils. All investigated profiles showed the influence of slope processes, resulting in heterogeneous soil profiles. The investigated soils can be described as polygenetic due to evidence of andisolization and the presence of salic and calcic diagnostic horizons. Andisolization implies development under a sub-humid paleoclimate during initial pedogenesis, while calcic and salic diagnostic horizons, are typical of the current arid conditions. As a result, about 63% of the investigated soils were classified as Torrands/Vitric Andosols and 37% as Salids/Solonchaks based on Soil Taxonomy and World Reference Base, respectively. Values of Alo, Feo, and Sio ranged from 0.20 to 0.68%, 0.24 to 3.27%, and 0.23 to 1.03%, respectively, implying the presence of poorly-crystalline fine components (i.e., allophane and ferrihydrite). Vermiculite, kaolinite, and interstratified vermiculite-chlorite were abundant, with illite, palygorskite, and Ca-zeolites as minor crystalline minerals. A combination of paleo/present-climate influenced pedogenesis leading to andisolization and the coexistence of poorly/crystalline minerals and formation of salic and calcic diagnostic horizons. This study demonstrates that andic properties can persist in dry-hot environments, highlighting the critical role of paleo/modern climate interactions as an influential factor driving the pedogenic pathways of VPMs-derived soils.

中文翻译：

---

沙特阿拉伯 Harrat Khaybar 火山成土作用的早期指标

摘要 古气候和当前条件对火山母质 (VPM) 上发育的土壤中成土作用的相互作用仍知之甚少，特别是对于干燥环境中的土壤。研究了位于沙特阿拉伯 Harrat Khaybar 并代表不同地貌和位置的八个代表性剖面，包括冲积平原、冲积扇、活动斜坡和熔岩场，以更好地了解气候和玄武岩岩性对成土作用的影响。对土壤的形态和物理化学性质以及粘土矿物组成进行了评估，以确定主要的诊断范围，从而确定产生所研究土壤的成土途径。所有调查的剖面都显示了坡度过程的影响，导致了异质的土壤剖面。调查的土壤可以被描述为多基因由于和孤立的证据以及存在水杨酸和钙质诊断层。Andisolization 意味着在初始成土过程中在半湿润古气候下发育，而钙质和唾液质诊断层是当前干旱条件的典型特征。因此，根据土壤分类法和世界参考基础，大约 63% 的调查土壤被分类为 Torrands/Vitric Andosols，37% 被分类为 Salids/Solonchaks。Alo、Feo 和 Sio 的值分别在 0.20 至 0.68%、0.24 至 3.27% 和 0.23 至 1.03% 的范围内，这意味着存在结晶性差的精细组分（即水铝石和水铁矿）。蛭石、高岭石和层间蛭石-绿泥石含量丰富，有伊利石、坡缕石、和钙沸石作为次要结晶矿物。古/现在气候的组合影响了成土作用，导致了孤立化和低结晶矿物的共存以及水杨酸和钙质诊断层的形成。这项研究表明，地基特性可以在干热环境中持续存在，突出了古/现代气候相互作用作为驱动 VPM 衍生土壤成土途径的影响因素的关键作用。