ABSTRACT

The Xaro sites are located in the Okavango Delta Panhandle of northwestern Botswana. All have an upper component with pottery identical to that made by nineteenth-century and current Mbukushu potters. Xaro 1 also has European glass beads for which cited historical documents provide calendar year dates of between 1850 and 1890. Other historical documents place the Xaro 1 Mbukushu settlement from the 1890s into the early twentieth century. All three Xaro Early Iron Age components have pottery motifs common at Tsodilo and Cubango sites on the basis of which a date range of the late sixth/early eighth centuries AD for Xaro 1 is most likely, while several pottery distinctions suggest a chronological separation within the same range for Xaro 2 and 3. Xaro Early Iron Age pottery has two unique features not discernible by the unaided eye but identified by microscopic optical petrography: 1) a red iron oxide veneer approximately two microns thick on outer surfaces; and 2) a variably thick post-deposition deposit of caliche derived from calcite suspended in Okavango water. A third uniqueness is an SEM estimated firing temperature of at least 1000^˚C, much higher than the ±800^˚C common for southern African vessels. Two Xaro burials provide aDNA data on Early Iron Age people in southern Africa; discriminant analysis of multiple variables determined that no present-day population sampled so far has the same ancestry mix, probably reflecting a northern genetic influence and offering genetic support to the hypothesis of a pre-Bantu expansion of pastoralists into southern Africa.

摘要

Xaro 站点位于博茨瓦纳西北部的奥卡万戈三角洲狭长地带。所有陶器的上部组件均采用与 19 世纪和当代 Mbukushu 陶艺家制作的陶器相同的陶器。Xaro 1 也有欧洲玻璃珠，引用的历史文件提供了 1850 年至 1890 年之间的日历年日期。其他历史文件将 Xaro 1 Mbukushu 定居点从 1890 年代追溯到二十世纪初。Xaro 早期铁器时代的所有三个组件都具有在 Tsodilo 和 Cubango 遗址中常见的陶器图案，根据这些图案，Xaro 1 最有可能是公元 6 世纪末/8 世纪初的日期范围，而几个陶器的区别表明在年代内的分离Xaro 2 和 3 的范围相同。Xaro 早期铁器时代的陶器有两个独特的特征，肉眼无法辨别，但可以通过显微光学岩相学识别：1) 外表面有一层约 2 微米厚的红色氧化铁贴面；2) 来自悬浮在 Okavango 水中的方解石的不同厚度的钙化石沉积后沉积物。第三个独特之处是 SEM 估计的燃烧温度至少为 1000^˚ C，远高于南部非洲船只常见的±800 ^{˚ C。}两个 Xaro 墓葬提供了南部非洲早期铁器时代人的 DNA 数据；对多个变量的判别分析确定，迄今为止抽样的现代人口没有相同的血统组合，这可能反映了北方的遗传影响，并为班图之前牧民向南部非洲扩张的假设提供了遗传支持。