Where did the Australasian tektites come from? A plain‑English recap of the “missing crater”

If tektites are the splash, where’s the splash mark? Here’s a clear, no‑jargon tour of what we know—and don’t.

1) Was there really a crater, and how big?

• Most researchers favor a low‑angle, high‑speed impact into the ground that made a real crater.
• Because the melt is so uniform across a huge area, it likely came from one big impact, not many small ones.
• Size estimates—based on how far the debris spread and by comparison with other tektite fields—suggest a crater roughly 30–40 km in diameter (or larger).

▲Figure 4 Estimated impact site locations for the Australasian tektite event by different researchers.

2) First stops: big basins on land

Scientists started with large round or oval depressions across Indochina—places like southern Laos (Savannakhet Basin, Muong Phin depression) and Cambodia’s Tonlé Sap. But careful fieldwork hasn’t found the smoking guns of an impact (like shocked minerals, shatter cones, or impact melt rocks) exposed there. The land search hit a wall.

3) Buried under lava?

A 2020 study of the Bolaven Plateau in southern Laos proposed that a crater might be hidden under young basalt lavas. Gravity data there show an anomaly about 17 × 13 km, and nearby thick, poorly sorted breccias include quartz grains with high‑pressure features—promising signs of ejecta blankets. Critics, including the late impact‑cratering pioneer H. Jay Melosh, countered that:

• A ~17 km crater seems too small to explain such a vast and uniform melt.
• Mixing basalt and sandstone during impact doesn’t match the tektites’ rare‑earth and isotope fingerprints.
• The near‑instant nature of an impact makes thorough mixing unlikely.

Verdict: intriguing clues, but not enough.

▲Figure 5 The impact crater is believed to be buried beneath the young basalt flows of the Bolaven Plateau in Laos.

4) Hidden in deserts?

Ideas have ranged far afield—from Kazakhstan’s Zhamanshin crater (too small, too far, and glass chemistry doesn’t match) to China’s Badain Jaran Desert in Inner Mongolia (a ~50 km ring‑like gravity anomaly). The desert idea leans heavily on assumptions; even the reported “microtektites” in Chinese loess were later shown to be fly‑ash contamination from sample handling. No firm evidence yet.

▲Figure 6 The southern Alxa Desert in Inner Mongolia is also considered a potential impact site.

5) Out to sea

Because river deltas and shallow seas can bury craters quickly, attention has shifted to places like the Mekong Delta, the Gulf of Thailand, and China’s Yinggehai Basin (off Hainan). These areas take in huge amounts of sediment or are under water—perfect for hiding a crater.

A fresh approach has been to stack all constraints together—tektite shapes and geography, microtektite abundance patterns, chemistry, rock types and ages in the likely source region, and regional geology—onto one base map. When you layer these lines of evidence, the Yinggehai Basin lights up as one of the higher‑probability targets. Still, this is a map‑based probability, not a discovery.

▲Figure 7 The Yinggehai Basin in China is another possible location of the impact crater (green area indicates high probability).

6) What would clinch it?

• High‑resolution geophysical surveys showing a ringed impact structure under sediments or lava.
• Drill cores that recover impact melt rocks, shocked minerals, and crater‑fill breccias with dates that match the tektites (~0.8 Ma).
• Geochemistry linking those melts to the known tektite composition.

Splash-form tektites are the top-tier collectibles among Leigong mo.

7) What’s next?

Expect more targeted geophysics and offshore drilling in promising basins, plus renewed field checks near any on‑land anomalies. Each new core or seismic line chips away at the mystery. When the crater is finally pinned down, it will tie a bow on one of planetary science’s longest‑running scavenger hunts.

Keep watching this space—the answer is likely hiding under young sediments or lava, waiting for the right instruments and a bit of luck.

References (same core set)

1. Tada, T. et al., 2020, Progress in Earth and Planetary Science, 7(1), 1–15.
2. Stauffer, M. R., Butler, S. L., 2010, Earth, Moon, and Planets, 107, 169–196.
3. Rochette, P. et al., 2018, Geology, 46(9), 803–806.
4. Jourdan, F. et al., 2019, Meteoritics & Planetary Science, 54(10), 2573–2591.
5. Tada, T. et al., 2022, Meteoritics & Planetary Science, 57(10), 1879–1901.
6. Sieh, K. et al., 2020, Proceedings of the National Academy of Sciences, 117(3), 1346–1353.
7. Mizera, J. et al., 2016, Earth‑Science Reviews, 154, 123–137.
8. Whymark, A., 2021, Thai Geoscience Journal, 2, 1–29.