The Venus Geologic Mappers' Handbook

Appendix D: Format Instructions for Text and Explanations

Headings and Head Notes

Within the description of map units and text, headings are divided into orders--major headings (Introduction, Physiographic Setting, Stratigrphy, Structural History, References Cited, Description of Map Units, etc.) are first-order centered headings and further subdivisions are second order and third order.

Type, centered:

FIRST-ORDER HEADINGS ALL CAPS AND BOLD

SECOND-ORDER HEADINGS ALL CAPS BUT NOT BOLD

Third-order headings initial cap and lowercase and not bold

[Headnotes under centered headings are enclosed in square brackets, extend across entire column width (except centered if only one or two lines long), are not indented, and have no final period]

Map Units and Symbols in DOMU

Type all map unit names at first mention in lowercase and bold; follow by two hyphens. Begin the descriptive material with a capital letter. Do not put a period at the end of the last line of the description of each unit and do not divide the description into paragraphs. Start the name of each first-rank map unit about ten spaces to the right of the first letter of the map unit symbol.

First rank--"Left margin"

  Second rank--Indent two spaces

    Third rank--Indent four spaces

        Fourth rank--Indent eight spaces

All overruns of all ranks--Indent six spaces if more than two ranks are used, four spaces for two ranks, and two spaces for one rank.

Use the same format for symbols (such as contact, fault, etc.) as for map units. On a geologic map, such symbols are explained following the description of map units and a break of about four blank lines but no separate heading.

Example of map explanation. The sample explanation below demonstrates the application of the above rules (text modified from a Mars map being prepared by S.L. Rotto and K.L. Tanaka). It is made much narrower than an actual explanation to allow room for marginal notes. Note that it is followed by a corresponding correlation chart.




	DESCRIPTION OF MAP UNITS [Map units distinguished and interpreted on basis of morphology, texture, albedo, and stratigraphic position. Although most map units are rock materials, some channel floors are also considered units in order to highlight erosional events that formed them]
	LOWLAND TERRAIN MATERIALS
	Chryse assemblage
	Basin materials--Form lowland plains below mouths of outflow channels; interpreted to consist of sediments derived from outflow channels and possibly volcanic and eolian deposits. Contacts between basin units generally gradational

	cr Subdued ridged unit--Plains marked by subdued wrinkle ridges and cut by small outflow channels. Interpretation: Ridged plains material partly resurfaced by outflow erosion and deposition

	cc Complex unit--Characterized by one or more of the following: (1) hummocky topography; (2) small knobs (some superposed on mesas); (3) sinuous depressions about 10 km wide and tens of kilometers long; (4) sinuous ridges less than 1 km wide, some of which are medial in sinuous depressions or connect knobs; (5) narrow, curvilinear, northeast- trending grooves; and (6) several mostly buried crater rims. Unit gradational with smooth and grooved basin materials. Interpretation: Relatively thick lacustrine deposits from most recent flooding. Various features result of fluvial or glacial processes (or both) and compaction of sediments


	cu Undivided unit--Material of Chryse assemblage occurring where image resolution does not permit discrimination of individual units

	Knobby materials--Interpreted as basin sediments and perhaps lava flows that embay knobs of older degraded plateau material
	ck Younger knobby material-- Forms knobby plains. Cut by lowermost Ares Vallis; gradational with older knobby material; embays mouth of Mawrth Vallis
	cku Upper unit--Found only in upper reaches of Kasei Valles in southwest quadrant of map area ckl Lower unit--Locally underlies upper unit but most exposures found in lower reaches of Kasei Valles in north-central part of map area cko Older knobby material--Closely spaced groups of knobs on high, undulatory plains along highland-lowland boundary (fig. 1). Typical exposures at lat 14.4_N., long 172_ (Viking frame 639A12)

	HIGHLAND TERRAIN MATERIALS
	Tharsis assemblage
	[Lava flows originating in Tharsis region] Tharsis Montes Formation-- Easternmost flows of large shields of Tharsis Montes; exposed in western part of map area

	t5 Member 5--Marked by elongate, high-albedo flow lobes with distinct margins; craters rare. Correlative with member 3 of Tharsis Montes Formation as mapped by Doakes(1983)