(LAC-60) Geologic map of the Julius Caesar quadrangle of the moon
Dates
Publication Date
1967-01-01
Time Period
1967-01-01
Citation
E. C. Morris, 19670101, (LAC-60) Geologic map of the Julius Caesar quadrangle of the moon: , https://doi.org/10.5066/P90BABNK.
Summary
The surface of the moon is heterogeneous. Surface materials are classed on the basis of telescopic observations into units each having a limited range of physical properties such as topography, visible under low-illumination and albedo, the reflectivity under full-Moon illumination. Such units are considered analogous to the rock-stratigraphic formations of terrestrial geology. By application of the principles of superposition and intersection, these rock units are arranged in order of relative age and grouped into time stratigraphic units. Following terrestrial contention, the major time-stratigraphic units are designated systems, and their subdivisions, series; corresponding to these units are periods and epochs of time, respectively [...]
Summary
The surface of the moon is heterogeneous. Surface materials are classed on the basis of telescopic observations into units each having a limited range of physical properties such as topography, visible under low-illumination and albedo, the reflectivity under full-Moon illumination. Such units are considered analogous to the rock-stratigraphic formations of terrestrial geology. By application of the principles of superposition and intersection, these rock units are arranged in order of relative age and grouped into time stratigraphic units. Following terrestrial contention, the major time-stratigraphic units are designated systems, and their subdivisions, series; corresponding to these units are periods and epochs of time, respectively (Shoemaker, 1962;Shoemaker and Hackman, 1962). The type localities of most of the systems and series recognized to date are in the vicinity of Mare Imbrium. The assignment of the various mappable rock-stratigraphic units to time-stratigraphic units is somewhat uncertain except in the type areas. Each unit is given either a descriptive designation or a formal stratigraphic name, and the letter symbol for each unit is composed of an abbreviation of its age assignment (capital) and name (lower case). Materials of each crater are together considered an informal formation, and the subunits, rim material, for example, are informal members. Features such as structural troughs, ridges, faults, and lineaments (in-distinct linear negative features) are indicated by symbols similar to the structural symbols of terrestrial geology. The descriptions of the units are arranged in chronologic order and include brief summaries of the visual characteristics and interpreted origins of each. Albedos are given in qualitative terms, which correspond to preliminary figures of Rovan and West (1965) as follows: very low, 0.12. The geologic mapping has been carried out to the precision obtainable with existing telescopic techniques; it has been aided in a small area near the southern map boundary by Ranger VIII photography. As more detailed information is acquired through lunar exploration, greater precision in discrimination and location of geologic units and structures and further refinement of their chronologic sequence is to be expected.
Digitized 1:1,000,000-scale geologic map of the LAC-60 Julius Caesar Quadrangle of the Moon. Originally mapped on Lunar Base Chart USAF-ACIC imagery. The scanned map sheet was imported into ArcMap and georeferenced to the more current 2013 global WAC mosaic basemap. Contacts and geologic units were digitized and attributed based on type and unit name.
