Iron-Rich Spherules of Taihu Lake: Origin Hypothesis of Taihu Lake Basin in China

In this paper, a detailed mineralogical study on iron-rich spherules in Taihu Lake was carried out, and we present proposed impact-related origin for these spherules. The spherical concretions occur specific silty layer formed around ~7 ka B.P., sandwiched between an upper lacustrine deposit lower hard loess layer, they are widely distributed the most abundant that vicinity of Lake. typically ~0.5 to 3 mm diameter with shape very similar but not exactly rounded have various apparent aerodynamic shapes, such as spherical, cone, spindle, ellipsoidal, elongated pear-shaped morphologies. SEM imaging shows there is no central core concentric layers Iron-rich accretionary lapilli typical colloidal structure angular quartz grains trace fragments clays wrapped fine cements mainly goethite minor carbon particles. nodule-forming mechanism aqueous sediments does sufficiently explain morphology internal features Lake, whereas aerosol formation under airburst impact hypothesis basin may be better explanation unique mineralogy Specifically, plumes could reaction chambers form texture interior, while dense shell semi-plastic morphological can falling processes from higher altitudes plume.