To investigate the structure of authigenic carbonates, synchrotron diffraction patterns of samples were measured with the Beamline P24 at 25.0 keV in DESY, Hamburg. Powder samples were inserted into glass capillaries with diameter of 0.5 mm and measured in Debye-Scherrer geometry. The distance between the sample and detector was 300.0 mm. During the exposure of 720 seconds, samples were spinned continuously by 90°. Signals were recorded by a MarCCD165 detector. Data were converted to 1D powder patterns based on the wavelength of Cu Kα radiation by the software package CrysAlisPro.

Yang Lu gratefully acknowledges the support of K. C. Wong Education Foundation and DAAD. U-Th dating was supported by grants from the National Taiwan University (NTU) Core Consortiums Project (112L894202), Higher Education Sprout Project of the Ministry of Education (112L901001).