Seven accelerator mass spectrometry radiocarbon (AMS 14C) dates (7260±106∼7607±95 BP averaged 7444±103 BP) on a giant oyster shell, collected from an ancient shore of the Taipei Basin, are similar to the LSC (liquid scintillation counting) 14C age (7260±46 BP) of a grass sample inside the shell. The calibrated 14C ages of the C. gigas by Marine20 are 7490±240∼7805±230 cal BP (average 7660±96 cal BP), generally agreed with the calibrated LSC 14C ages of the grass and the oyster shell. Combined with other 14C ages of shoreline samples in the Taipei Basin, it is evident that sea level rose from 8600 to 7600 cal BP and reached a stand higher than modern sea level. During this marine transgression, the sedimentation rate along the shoreline was very high because 14C dating was not able to detect age differences for 4–5 m thick sediment sequences. Sixty-nine analyses of δ18O and δ13C from the oldest part of the shell exhibit clear seasonal cycles, with a 4-year period of growth in the 5.5-cm section. According to the δ18O values, the ancient oyster grew in a warmer-than-present shoreline environment, suggesting that the current absence of the giant oyster in Taiwan is not due to warming conditions.

Holocene shore-face and beach-face deposits form plains <5 m above present sea level along Taiwan Strait. We measured the 14C ages of detrital mollusk shells and coral in such deposits at the Penghu Islands. Twelve carbonate samples—mainly from the largest island, Makung—were dated. Age measurements for two coral samples and one mollusk sample from the same outcrop imply that the 14C ages of mollusk shells give the best approximation of depositional age. The highest Holocene relative sea level in the Penghu Islands occurred about 4700 years ago with a height about 2.4 m above the present sea level. Thereafter, relative sea level appreciably fell without detectable fluctuations to its recent position. Our sea level data are consistent with other studies from the central and western Pacific, except for the timing of peak sea level position. This variation may reflect local crustal response to hydroisostatic effects on the continental shelf.

The glyptodont (Glyptodontidae Burmeister 1879, in Ameghino 1889), a giant cousin of the armadillo, has long been thought to have disappeared in South America at least 10,000 years ago at the end of the Pleistocene. There are indications that the glyptodont had some interaction with ancient hunter-gatherers peoples (Politis et al. 1987; Politis 1995), but the precise time of its extinction has never been well established. Most recently, a brief mention of 14C dates of 7500 to 6500 BP (Geotimes 1996) for glyptodont remains discovered at La Moderna (Azul Department, Buenos Aires province, Argentina), has aroused excitement because the new younger dates have changed the traditional idea about the survival and extinction of this beast.

The Choushuichi alluvial-fan delta is the largest groundwater system in Taiwan. The coastal area of this fan delta has recently suffered severe land subsidence and sea-water intrusion due to overpumping of groundwater. To study the hydrogeological character of proper water-resource management, an intensive program of geological and water monitoring through well drilling and sampling has been undertaken. At present, radiocarbon dating and/or tritium analysis for samples from >70 boreholes has been completed. The clearly defined position of “bomb-tritium front” allows the groundwater flow and recharge rates of the confined aquifer to be calculated with confidence at <10 m yr−1 and 9.0 × 108 m3 yr−1, respectively. The flow velocities of the confined aquifer have also accelerated remarkably due to much pumping during the last decades.

This list consists of radiocarbon dates for geological samples measured from 1988 to 1990 at the resumed National Taiwan University (NTU) Radiocarbon Dating Laboratory. The NTU Radiocarbon Dating Laboratory was re-activated in 1988, after more than 14 years.