HKU Geologists reveal diverse volcanism in Lunar Apollo Basin, Chang'e-6 landing site

HKU Geologists reveal diverse volcanism in Lunar Apollo Basin, Chang'e-6 landing site
by Simon Mansfield
Sydney, Australia (SPX) May 08, 2024

The farside of the Moon has long been a subject of intrigue, particularly because it remains hidden from view on Earth. The most notable aspect of the Moon is the distinct difference in composition, crust thickness, and volcanic activity between the nearside and farside. The origin of these asymmetries remains unresolved, primarily due to a lack of samples from the farside, representing a major unresolved question in lunar science.

The Chang'e-6 mission, launched on May 3, 2024, and currently en route to the Moon, marks the first attempt to return samples from the lunar farside. It aims to collect approximately 2 kg of lunar soils from the southern mare of the Apollo basin within the South Pole-Aitken basin, the largest impact basin in the Solar System. These samples are expected to offer new insights that could address the longstanding questions about lunar dichotomy.

Recent findings from a study published in Earth and Planetary Science Letters by Dr. Yuqi Qian, Professors Joseph Michalski and Guochun Zhao from the University of Hong Kong, along with their international colleagues, have shed light on the diverse and extensive volcanic activity in the Apollo basin, the designated Chang'e-6 landing site. The research indicates significant variations in volcanic activity linked to crustal thickness variations across the region.

Volcanic activity in the Apollo basin dates back from the Nectarian period (approximately 4.05 billion years ago) to the Eratosthenian period (around 1.79 billion years ago). Dr. Qian explained, "This fundamental finding indicates that the crustal thickness discrepancy between nearside and farside may be the primary cause of lunar asymmetrical volcanism," said Dr Qian. "This can be tested by the returned Chang'e-6 samples."

In the southern mare of the Apollo basin, the target area for Chang'e-6, at least two volcanic episodes have been identified. The first, occurring around 3.34 billion years ago, involved low-Ti basalts that covered a broad low-lying area between the Apollo peak ring and basin rim. A later eruption, around 3.07 billion years ago, produced high-Ti basalts near Chaffee S crater, extending eastward with diminishing thickness towards proto-wrinkle ridges.

"The diverse sample sources from these regions are expected to provide crucial data for addressing several unanswered questions about the lunar conditions," highlighted Professor Michalski. Professor Zhao added, "The results from our study will be instrumental in analyzing the soon-to-be-returned samples by Chang'e-6, contributing significantly to our understanding of lunar geology and aiding in the advancement of planetary sciences at HKU."

HKU's involvement in the acquisition of lunar samples from both the nearside and farside aims to enhance its role in the national space program and broaden the scope of scientific inquiry into the Moon's contrasting hemispheres.

Research Report:Long-lasting farside volcanism in the Apollo basin: Chang'e-6 landing site