We have used electron probe microanalysis to examine Southeast Asian nephrite (jade) artifacts, many archeologically excavated, dating from 3000 B.C. through the first millennium A.D. The research has revealed the existence of one of the most extensive sea-based trade networks of a single geological material in the prehistoric world. Green nephrite from a source in eastern Taiwan was used to make two very specific forms of ear pendant that were distributed, between 500 B.C. and 500 A.D., through the Philippines, East Malaysia, southern Vietnam, and peninsular Thailand, forming a 3,000-km-diameter halo around the southern and eastern coastlines of the South China Sea. Other Taiwan nephrite artifacts, especially beads and bracelets, were distributed earlier during Neolithic times throughout Taiwan and from Taiwan into the Philippines.
The prehistoric cultures involved are from the Neolithic in Taiwan and the Philippines, and the Early Iron age across a much larger area of the South China Sea.
Too bad this is not an open access article (at least not yet). The upshot, obviously, is that there is much more exchange, trade, or movement across a fairly large area than previously thought. Here is a section of a map from the PNAS piece:
Notice that even with some adjustment (which may not be necessary) of eustatic sea level and/or tectonics, much of this area is across oceanic areas. The authors note that this is probably a minimal estimate as many areas have not been included in this study that could be in the future.
Hsiao-Chun Hung, Yoshiyuki Iizuka, Peter Bellwood, Kim Dung Nguyen, BÃ©rÃ©nice Bellina, Praon Silapanth, Eusebio Dizon, Rey Santiago, Ipoi Datan, and Jonathan H. Manton. (2007) Ancient jades map 3,000 years of prehistoric exchange in Southeast Asia PNAS published November 29, 2007, 10.1073/pnas.0707304104.