# Sourcing the origins of carnelian in early Chinese civilizations

## TL;DR

This study identifies the origins of carnelian beads in ancient China, revealing long-distance trade networks spanning over 1,000 km during the Bronze Age.

## Contribution

A geochemical database and LA-ICP-MS analysis enable the first direct evidence of long-distance carnelian exchange in Bronze Age China.

## Key findings

- Carnelian beads from Sanxingdui originated from northern sources like the Yanshan Orogeny and Central Asian Orogenic Belt.
- Similar northern provenance signatures in beads from Gansu, Shaanxi, and Beijing suggest a broad exchange network.
- The study provides the earliest geochemical evidence of long-distance carnelian trade in Bronze Age China.

## Abstract

Understanding the origin of materials in prehistoric ornaments is vital for studying ancient trade and interaction networks. This research presents the large-scale, consistently analyzed geochemical reference database for carnelian in East Asia, encompassing 27 geological sources from diverse regions. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) trace element fingerprinting and canonical discriminant analysis, we achieved over 90% accuracy in identifying carnelian origins. Applying this method to beads from Sanxingdui and other contemporary sites reveals extensive long-distance material networks linking the Sichuan Basin with northern China. These results highlight significant interregional exchanges and offer a universal protocol for sourcing microcrystalline quartz artifacts worldwide.

Carnelian beads in high-status burials of the Western Zhou period (ca. 1000–800 BCE) have long been seen as key evidence for long-distance exchange between East Asia and regions to the west, while their geological origins and circulation pathways have remained poorly constrained. Using a newly established geochemical database of 300 geological samples from 27 potential sources across Asia, we conducted trace-element analyses of 11 carnelian beads from the Sanxingdui pits (ca. 1200–1000 BCE), Sichuan Basin, southwest China. Canonical discriminant analysis indicates that the raw materials of these carnelian beads do not primarily derive from south China, but the Yanshan Orogeny, Central Asian Orogenic Belt and some unknown sources that might be close to Hexi Corridor, pointing to raw-material sources located over 1,000 km to the north of the Sichuan Basin. Comparative analyses of contemporaneous beads from Gansu, Shaanxi, and Beijing show similar northern provenance signatures, suggesting a broad and persistent exchange sphere spanning the southern Mongolian Plateau, Loess Plateau, eastern Tibetan Plateau, Central Plains, and Sichuan Basin between 1500–1000 BCE. Our results provide the earliest direct geochemical evidence for long-distance carnelian exchange in Bronze Age China and demonstrate the value of integrating geochemical sourcing with archaeological context to reconstruct ancient interaction networks.