Mare Frigoris

Mare Frigoris

Mare Frigoris is a lunar mare located in the northern region of the near side of the Moon. It lies between the Mare Imbrium basin to the southwest and the Mare Serenitatis–Mare Tranquillitatis complex to the southeast, forming a broad, irregular band of basaltic plains that link several highland features such as the Caucasus Mountains (Moon) and the Apennine Mountains (Moon). Its extent and morphology have made it a subject of mapping by missions including Lunar Reconnaissance Orbiter, Apollo 15, and Clementine.

Overview

Mare Frigoris occupies a latitudinal belt north of the Mare Imbrium and west of the Oceanus Procellarum, bordered by craters like Plato (crater), Eratosthenes (crater), and Bessel (crater). It connects with basaltic regions such as Lacus Mortis and Lacus Somniorum and is adjacent to highland terrain including the Alpine Valley and the Montes Alpes (Moon). The mare has been imaged by spacecraft from programs like Luna programme, Ranger program, and Surveyor program and observed telescopically by astronomers including Giovanni Riccioli, Johannes Hevelius, and Galileo Galilei.

Geology and Composition

The surface of Mare Frigoris consists predominantly of mare basalts with volcanic flow morphologies similar to those found in Mare Imbrium and Mare Tranquillitatis. Spectroscopic measurements by instruments aboard Chandrayaan-1, Kaguya (SELENE), and Lunar Prospector indicate variations in titanium and iron content comparable to basalts from Mare Crisium and Mare Humorum. Regolith in the region contains impact ejecta from basins such as Orientale basin and Nectaris basin, and layers include highland anorthositic material linked to the Procellarum KREEP Terrane and to episodes cataloged by investigators from Smithsonian Astrophysical Observatory and NASA. The mare exhibits wrinkle ridges, sinuous rilles, and flow fronts that have been mapped using data from Clementine multispectral imaging and laser altimetry from Lunar Orbiter Laser Altimeter.

Age and Formation

Radiometric and crater-count dating constrained by samples from analogous mare locations and calibrated by stratigraphic relationships with features like the Imbrium sculpture suggest that Mare Frigoris basalts erupted during the Upper Imbrian to Eratosthenian epochs, contemporaneous with flows in Mare Serenitatis and Mare Insularum. Its formation is linked to volcanic effusion following large-impact events such as the formation of the Imbrium basin and modification by subsequent impacts from projectiles originating in populations studied by teams at Jet Propulsion Laboratory and European Space Agency. Geochronological models from researchers at Brown University, California Institute of Technology, and Massachusetts Institute of Technology use crater size-frequency distributions to estimate emplacement ages and to compare them with Apollo sample ages from Apollo 11, Apollo 12, and Apollo 15 landing sites.

Nomenclature and Exploration History

The name derives from early lunar cartographers; the mare was labeled in lunar maps by Giovanni Battista Riccioli and later cataloged by Johann Heinrich von Mädler and Wilhelm Beer. It has been included in modern nomenclature maintained by the International Astronomical Union. Exploration of the area has been indirect: orbital remote sensing from missions such as Lunar Reconnaissance Orbiter, Clementine, Kaguya (SELENE), Chandrayaan-1, and Lunar Prospector provided photographic, spectral, and gravity data; gravity anomalies over the mare were investigated by teams from Goddard Space Flight Center and Ames Research Center. Historical Earth-based telescopic surveys by William Herschel, Johann Schröter, and William H. Pickering contributed to early morphological descriptions that informed later mission targeting by NASA and by agencies like Roscosmos.

Observations and Notable Features

Mare Frigoris displays a heterogeneous albedo and is intersected by prominent crater chains and individual craters such as J. Herschel (crater), Anaximander (crater), and Babbage (crater). The mare’s northern reaches transition into the rough terrain of Mare Frigoris High, where features recorded in digital elevation models from Lunar Reconnaissance Orbiter Camera show faults, graben, and lava ponds analogous to those observed in Mare Moscoviense and Mare Ingenii. Anomalous magnetic signatures measured by Lunar Prospector and modeled by researchers at University of Arizona and University College London suggest localized remanent magnetization possibly related to impact processes studied in context with the South Pole–Aitken basin and the Procellarum KREEP Terrane. Remote detections of pyroclastic deposits and potential volcanic constructs link Mare Frigoris to global lunar volcanism themes explored by teams at Brown University and University of Hawaii. Its visibility from Earth makes it a target for amateur observers using equipment from manufacturers like Celestron, Meade Instruments, and institutions such as the Royal Astronomical Society and the American Astronomical Society.

Category:Lunar maria