Int. J. Mol. Sci. 2011, 12, 6051-6076; doi:10.3390/ijms12096051 OPEN ACCESS International Journal of Molecular Sciences ISSN 1422-0067 www.mdpi.com/journal/ijms Article Academic Aspects of Lunar Water Resources and Their Relevance to Lunar Protolife Jack Green Department of Geological Sciences, California State University, Long Beach, CA 90840, USA; E-Mail:
[email protected]; Tel.: +1-562-985-4198; Fax: +1-562-985-8638 Received: 4 August 2011 / Accepted: 31 August 2011 / Published: 19 September 2011 Abstract: Water ice has been discovered on the moon by radar backscatter at the North Pole and by spectrometry at the South Pole in the Cabeus crater with an extrapolated volume for both poles of conservatively 109 metric tons. Various exogenic and endogenic sources of this water have been proposed. This paper focuses on endogenic water sources by fumaroles and hot springs in shadowed polar craters. A survey of theoretical and morphological details supports a volcanic model. Release of water and other constituents by defluidization over geological time was intensified in the Hadean Eon (c.a. 4600 to 4000 My). Intensification factors include higher heat flow by now-extinct radionuclides, tidal flexing and higher core temperatures. Lesser gravity would promote deeper bubble nucleation in lunar magmas, slower rise rates of gases and enhanced subsidence of lunar caldera floors. Hadean volcanism would likely have been more intense and regional in nature as opposed to suture-controlled location of calderas in Phanerozoic Benioff-style subduction environments. Seventy-seven morphological, remote sensing and return sample features were categorized into five categories ranging from a volcano-tectonic origin only to impact origin only.