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Prepared for the

National Aeronautics and Space Administration

U.S. Department of the Interior

U.S. Geological Survey

Printed on recycled paper

Any use of trade, product, or firm names in this publication is for 

descriptive purposes only and does not imply endorsement by the U.S. 

Government

For sale by U.S. Geological Survey, Information Services, Box 25286, 

Federal Center, Denver, CO 80225, 1–888–ASK–USGS

Available at http://pubs.usgs.gov/sim/3026

Geologic Map of the Helen Planitia Quadrangle (V–52), Venus

By

Iván López1 and Vicki L. Hansen2

2008

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270°

SCALE 1:4 711 886 (1 mm = 4.712 km) AT –25° LATITUDE

1:5 000 000 AT –34° and –73° LATITUDES

LAMBERT PROJECTION

500 400 300 200 100 0 KILOMETERS100 200 300 400 500

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180° 210° 240° 270° 300° 330° 360°

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V–1

V–29 V–30 V–28

V–40

V–62

V–41

V–27

V–26

V–15

V–14

V–16

V–39 V–42

V–18

V–51 V–54

V–17

V–53

V–60

V–6

V–5

V–19

V–50 V–55

V–31

V–38 V–43

V–7

V–59 V–61

QUADRANGLE LOCATION

Photomosaic showing location of map area. An outline of 

1:5,000,000-scale quadrangles is provided for reference.

1Departamento de Biología y Geología, 

 Universidad Rey Juan Carlos, Madrid, Spain

2Department of Geological Sciences,

 University of Minnesota-Duluth, Duluth, MN

V–52

DESCRIPTION OF MAP UNITS

[The absence of distinctive temporal markers and robust impact-crater dating techniques (Hauck and others, 1998; Campbell, 1999) precludes correlation of units across the map area. Instead of the classical order of unit descriptions from 

younger to older, we list units by geographic location within the Parga Chasmata (PCR) and Helen Planitia (HPR) regions 

and subregions (western, central, and eastern); units that are in contact with and (or) interact with various structures or 

suites of structures provide local temporal relations]

PARGA CHASMATA REGION

Western Area

Shield field and associated material around Sitapi Coronae—Variable backscatter and 

variable textured materials with different morphologies that form edifices 10–20 km diameter. Shields form clusters locally associated with Sitapi Coronae. Deformed by local corona 

fracture suites and regional northwest-striking fractures. Type locality: Lat 33.5° S., long 

243° E. Interpretation: Composite shield unit that cannot be used as a marker unit across the 

map area.

Flow material from Hlineu Corona—Intermediate to low backscatter and homogeneous 

texture. Intermediate-size volcanic features and clusters of shields inside and around the 

corona contribute to the unit. Locally cut by corona-related concentric fractures, northweststriking regional fractures, and north-trending wrinkle ridges. Type locality: Lat 35° S., long 

241° E. Interpretation: Lava flows related to formation of Hlineu Corona.

Flow material from Azimua Tholi—High backscatter and reticulate to mottled texture. The 

origin of the material is unclear. Partially covered by an apron related to lateral flank failure 

of a near steep-sided dome. The material is deformed by northwest-trending wrinkle ridges 

and northeast-striking fractures. Type locality: Lat 34° S., long 248.8° E. Interpretation: 

Volcanic flows of undetermined origin.

Flow material from Destinnová Patera—Intermediate backscatter and homogenous texture. 

Comprises flows that emerged to the north and radial flows near the caldera. Deformed by 

north-trending wrinkle ridges. Type locality: Lat 31.5° S., long 250° E. Interpretation: Volcanic flows associated with Destinnová Patera.

Flow material from Witte Patera—Intermediate- to high-backscatter flows. Comprises numerous individual flows radiating from Witte Patera (lat 25.8° S., long 247.6° E.). Materials are 

cut by local fracture suites and by fractures and graben of Parga Chasmata. Unit correlates 

with corona material, undivided (unit co) of the Galindo quadrangle (V–40; Chapman, 

1999). Type locality: Lat 26.2° S., long 247.2° E. Interpretation: Volcanic flows related to 

Witte Patera.

Flow material from Lalohonua Corona—Intermediate to high backscatter. Unit is composed of 

multiple overlapping flows that display homogeneous texture and lobate to sheet-like flow 

morphologies. Flows are locally cut by fractures and graben of Parga Chasmata. Correlates 

with corona materials, unit m (unit com) of the Galindo quadrangle (V–40; Chapman, 1999). 

Type locality: Lat 26° S., long 250° E. Interpretation: Lava flows related to Lalohonua 

Corona.

Parga Chasmata material a—Intermediate to high backscatter. Preserved as a local topographic 

high. Contains shields (age unknown). Extensively deformed by north- and northweststriking fractures, northwest-trending graben, and local fracture suites. Type locality: Lat 

28.5° S., long 254.5° E. Interpretation: Volcanic materials that postdate local tessera terrain. 

Locally deformed by a pervasive deformation fabric. This unit could represent materials 

formed before the formation of Parga Chasmata, preserved within the extensional deformation belt, or emplaced during initial stages of extensional deformation belt evolution. 

Predates adjacent corona-related lava flows (unit fchP).

Central Area

Shield field near Monoshi Tholus—Intermediate backscatter. Discontinuous layer resulting 

from the point-sourced nature of the shield-related flows and deposits. Deformed by a local 

radial fracture system. Some shields appear to be aligned along fractures, suggesting tectonic 

control of emplacement. Type locality: Lat 36° S., long 252° E. Interpretation: Local volcanic shield field and associated volcanic materials.

Flow material from Monoshi Tholus—Intermediate backscatter and mottled texture. Composite unit made of volcano-related flows and shields. A radial fracture system associated with 

Monoshi Tholus cuts, but is also partially covered by, materials of the unit. Type locality: Lat 

38.6° S., long 251.2° E. Interpretation: Volcanic flows associated with Monoshi Tholus and 

shield-related materials.

Flow material from Oanuava Coronae and Achall Corona—Moderate to high backscatter and 

smooth to reticulate texture. Includes sheet flows related to Oanuava Coronae and Achall 

Corona and materials related to intermediate-size volcanoes, shield fields, and associated 

flow materials formed in the interior of the large coronae. Locally fractured by coronarelated fractures and by graben of Parga Chasmata. Type locality: Lat 32° S., long 252.5° E. 

Interpretation: Lava flows from Oanuava Coronae and Achall Corona, local intermediatesize volcanic features, and shield-related materials; composite unit that cannot be used as a 

temporal reference marker unit.

Flow material from fractures and coronae of Parga Chasmata—Variable backscatter and 

texture. Composite unit formed by digitate to lobate flows that emerged from fractures of 

Parga Chasmata; Kulimina, Hervor, and Xmukane Coronae; and an unnamed nova located at 

lat 27.5° S., long 267.5° E. Flow indicators mapped on the basis of lobate and digitate flow 

boundaries and the presence of primary structures, such as channels, that indicate the source 

of some flows. Locally deformed by corona-related fracture suites, the fractures and graben 

of Parga Chasmata, and north-trending wrinkle ridges. Correlates with flow materials, unit 2 

(unit f2) and corona material, undivided (unit co) of the Galindo quadrangle (V–40; 

Chapman, 1999). Type locality: Lat 27° S., long 259° E. Interpretation: Lava flows related to 

Parga Chasmata; Kulimina, Hervor, and Xmukane Coronae; and an unnamed nova; composite unit that cannot be used as a temporal reference marker unit.

Flows and shield-related materials around Zerine crater—High to intermediate backscatter. 

Composite unit composed of lobate flows related to an unnamed corona (lat 28.5° S., long 

258° E.) and shield fields with associated flow materials; locally cut by local corona-related 

fracture suites and structures of Parga Chasmata. Type locality: Lat 28.5° S., long 256.8° E. 

Interpretation: Corona-related lava flows and local shield fields with associated flows; 

composite unit that cannot be used as a temporal reference marker unit.

Eastern Area

Flow material from Otohime Tholus—Intermediate to high backscatter flows associated with 

Otohime Tholus (lat 32° S., long 268.2° E). Locally cut by regional fractures. Type locality: 

Lat 32.2° S., 268.2° E. Interpretation: Local flows related to formation of the Otohime 

Tholus.

Flow material from Mertseger Mons—Low- to intermediate-backscatter flows associated with 

Mertseger Mons (lat 38.1° S., long 270.3° E.); shields locally present. Flow indicators 

mapped on the basis of lobate and digitate flow boundaries. Cut by radial fractures of 

Mertseger Mons. Type locality: Lat 39° S., long 269.5° E. Interpretation: Local shields and 

volcanic flows related to formation of Mertseger Mons.

Shield field and associated materials near Nordenflycht Patera—Low backscatter and homogeneous textured materials that form small shields with summit pit craters. Deformed by 

northeast-striking fractures and wrinkle ridges. Type locality: Lat 36.5° S., long 267° E. 

Interpretation: Volcanic shields associated with a local tectonomagmatic feature.

Parga Chasmata material b—High backscatter. Preserved as local topographic highs. Extensively deformed by local nova-related deformation suites and by fractures and graben of 

Parga Chasmata. Type locality: Lat 27.5° S., long 267° E. Interpretation: Material of 

unknown genetic origin deformed by a pervasive deformation fabric. This unit could represent materials formed before the formation of Parga Chasmata and preserved within the 

extensional deformation belt or materials emplaced during initial stages of extensional deformation belt evolution. Predates adjacent corona-related lava flows (unit fchP).

Parga Chasmata material c—Intermediate to high backscatter and homogeneous to mottled 

texture. Contains shields and intermediate-size volcanic features with associated flows. 

Locally cut by a local reticulate fracture fabric, as well as fractures, graben of Parga Chasmata, and wrinkle ridges. Type locality: Lat 33.8° S., long 268° E. Interpretation: Lava flows 

and other volcanic-related materials of unknown age. Predates adjacent chasma- and 

corona-related flows (unit fchP).

HELEN PLANITIA REGION

Western Area

Shield field and associated material of Sopdet Tesserae—Intermediate backscatter and local 

reticulate texture material formed by small shields with summit pit craters and associated 

flows. Type locality: Lat 43.5° S., long 242° E. Interpretation: Local volcanic shields and 

associated materials that postdate tessera terrain in Sopdet Tesserae terrain.

Central Area

Flow material from Ne Ngam Mons—Intermediate backscatter flows. Flow indicators mapped 

on the basis of lobate and digitate flow boundaries and channels that indicate emplacement 

style. Interacts with Ajina Fossae. Type locality: Lat 43° S., long 256.8° E. Interpretation: 

Volcanic flows related to the formation of Ne Ngam Mons.

Helen Planitia materials, undivided—Intermediate to high backscatter with textures that vary 

from homogeneous to a kilometer-scale reticulate texture. Backscatter variations caused by 

the mantling of Adaiah’s halo. Contains shields and associated shield material. Locally 

deformed by north-northeast wrinkle ridges, northwest-trending folds in Tsovinar Dorsa, 

local fracture suites, and regional fracture suites. Type locality: Lat 41.7° S., long 251° E. 

Interpretation: Lava flows and other volcanic-related materials that locally postdate the 

tessera terrain. Predates adjacent heterogeneous materials and shield related materials.

Eastern Area

Flow material from Abeona Mons—Low- to intermediate-backscatter material. Flow indicators mapped on the basis of digitate flow boundaries. Flows bounded by unit tu. Type locality: Lat 46° S., long 270° E. Interpretation: Distal volcanic flows related to the formation of 

Abeona Mons in the Themis Regio quadrangle (V–53).

Shield field and associated materials of Enekeler Corona—Intermediate backscatter and local 

reticulate texture. Clusters of shields that form continuous patches of shield-related material 

inside Enekeler Corona. Type locality: Lat 46.5° S., long 264° E. Interpretation: Local volcanic shields associated with Enekeler Corona.

Flows and shield-related materials around Ustrecha Tesserae—Intermediate- to 

low-backscatter materials of heterogeneous texture. Composed of shield clusters and distributed shields that cover most of the eastern map area. Spatially related to large tectonomagmatic features and regional fracture suites. Interacts with the circum-Themis-trend wrinkle 

ridges (Billoti and Suppe, 1999). Type locality: Lat 41° S., long 261.5° E. Interpretation: 

Composite shield-related volcanic materials; unlikely to represent a single coherent stratigraphic unit across the map area.

WIDESPREAD MATERIALS

Crater material—High backscatter and blocky texture. Includes ejecta blanket and central peak. 

Type locality: Lat 29.5° S., long 241° E. Interpretation: Materials and structures formed 

during the formation of an impact crater.

Crater flow material—Intermediate to bright material associated with impact craters. In some 

locations, material was channeled through fractures. Type locality: Lat 29.5° S., long 241° E. 

Interpretation: Low viscosity impact melt or fluidized ejecta created by bolide impact.

Heterogeneous material, undivided—Low- to high-backscatter material with heterogeneous 

texture. Internally discontinuous flow boundaries. Volcanic primary structures include 

channels and numerous shields that appear locally clustered. Corona-related fracture suites, 

regional fractures, and wrinkle ridges locally cut materials. Correlates with flow materials, 

unit 2 (unit f2) of the Galindo quadrangle (V–40; Chapman, 1999) and regional plains material (unit pr) of the Barrymore quadrangle (V–59; Johnson and others, 1999). Type locality: 

Heterogeneous unit without a single type locality. Interpretation: Composite unit of various 

materials from local shield-related materials to large-scale, corona-related flows. The 

composite nature of this unit precludes its use as a marker unit across the map area.

Tessera terrain, undivided—High backscatter, topographically rough, relatively high relief. 

Extensively deformed by suites of ribbon fabrics, folds, graben, and local and regional 

fractures. Individual inliers display different structural assemblages and deformational histories. In some locations, structures show variable evidence of structural reactivation. Type 

locality: Lat 50° S., long 263° E. Interpretation: Materials of unknown genetic origin 

variably deformed by ribbon fabrics, folds, and graben formation during a progressive thickening of a thin mechanical layer (Hansen and Willis, 1998; Hansen, 2006).

MAP EXPLANATION

Contact—Dashed where approximately located

Gradational contact

Primary structures

 Radar boundary

 Canali

 Shield—Diameter <10 km

 Intermediate volcanoes

 Modified or fluted intermediate volcanoes

 Crater rim crest

 Pit chain

 Small depression—Sometimes interpreted as calderas

Flow direction

 Lobate front

 Hummocky terrain—Related to lateral flank failure processes

Dark splotch

 Halo

Secondary structures

 Regional fracture—Shown with ball where interpreted as graben

Local radial fracture—Shown with ball where interpreted as graben

Local concentric fracture—Shown with ball where interpreted as graben

Area of high fracture density

 Broad topographic ridges or warps

 Folds

 Wrinkle ridges

 Ribbon fabric—Dashed where evidence of reactivation

240°

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Figure 1. SAR image of Helen Planitia quadrangle (V–52), Venus. A. Showing major features (leftlooking radar image in Lambert projection). B. Showing the Parga Chasmata and Helen Planitia regions 

and subregions defined by local geologic histories.

240°

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Figure 2. Ancillary data sets for Helen Planitia quadrangle (V–52), Venus: A, Altimetry (Global Topography Data Record 3.1; color stretch is nonlinear to bring out topographic details); B, Reflectivity showing 

efficiency of surface materials in reflecting electron radiation; C, Root mean square (RMS) slope; D, Emissivity showing that rough areas and low dielectric content materials have higher values. 6,054

6,050.81

6,0516,0526,053

6,051.84

(MPR)

1.0 0.75 0.50 0.25 0.125 0.0

12.552 10 8 4 6 2 0.2

RMS Slope (degree)

0.99 0.8 0.9 0.7 0.50.6 0.4 0.3

Emissivity

Corrected Reflectivity

Planetary radius (km)

A B

C D

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HELEN PLANITIA REGION

PARGA CHASMATA REGION

Western area Eastern area

Western area Eastern area

Central area

Central area

240°

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Figure 4. Map of regional (blue) and local (green) fracture suites underlain by altimetry data, 

Helen Planitia quadrangle (V–52), Venus. The figure also shows the location of large tectonomagmatic features (red lines, corona annuli) and radial fracture systems (brown lines): a, center of 

structure centered on Darclée Patera; b, structure centered on Monoshi Tholus; c, structure 

centered on caldera located at lat 40.5° S., long 258° E.

b a

c

unnamed

corona

unnamed

corona

unnamed

corona

unnamed

corona

unnamed

nova

?

?

6,054

6,050.81

6,0516,0526,053

6,051.84

(MPR)

Planetary radius (km)

240°

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270°

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Figure 3. Map showing structural ridges underlain by altimetry data, Helen Planitia quadrangle 

(V–52), Venus.

6,054

6,050.81

6,0516,0526,053

6,051.84

(MPR)

Planetary radius (km)

circum-Themis trend

Helen Planitia trend

North-trending wrinkle ridges

A B

Scientific Investigations Map 3026

Atlas of Venus: Helen Planitia Quadrangle (V–52)

Pamphlet accompanies map

Prepared on behalf of the Planetary Geology and Geophysics Program, 

Solar System Exploration Division, Office of Space Science, National 

Aeronautics and Space Administration

Cartography by Darlene A. Ryan

Manuscript approved for publication May 12, 2008

fsU

hu

fcOA

huhu hu

pHu

fcOA

fsZ

fcH

sfSi

ftA

tu

MooreXeniaKanikWollstonecraftSteinbachShasenemAdaiah

Ustinya

ZerineViolaRose

Western Area Central Area Eastern Area Structures Structures

WIDESPREAD MATERIALS RELATIVE AGE RANGE OF IMPACTS

Western Area Central Area Eastern Area

 Wrinkle ridge formation

 Local fracture suites (radial fracture systems and fractures related

to large tectonomagmatic structures)

Fold formation

Regional fracture suites (northwest-striking fracture suite and Parga Chasmata)

Warp or broad topographic ridge

Wrinkle ridge formation (Helen and circum-Themis trends)

Local fracture suites (radial fracture systems and fractures related

to large tectonomagmatic structures)

Fold formation

Local fractures North-striking fracture suite

Warp or broad topographic ridge

Tessera-terrain

ribbons

Reactivation(?)

Tessera-terrain

ribbons

PARGA CHASMATA REGION (PCR) HELEN PLANITIA REGION (HPR)

SEQUENCE OF MAP UNITS, STRUCTURES, AND IMPACT CRATERS

[These diagrams present the local stratigraphic sequences in V–52. Correlations between sequences cannot be robustly constrained]

Time

transgressive contact

Heterogeneous material

undivided (unit hu)

locally postdates unit A

Heterogeneous material

undivided (unit hu)

locally predates unit B

A

B

KEY

Stratigraphic position of base/top of unit 

poorly constratined (or uncertain)

Part of the local 

stratigraphic sequence over 

which a time-trangressive 

structural suite may have 

formed (solid line indicates 

greater confidence)

Stratigraphic position of base/top 

of unit poorly constrained (or 

uncertain)

Zerine

Monoshi

Tholus

PARGA CHASMATA

Mertseger

Mons

Ne Ngam

Mons

Tsovinar

Dorsa

Giltine Tesserae

Wollstonecraft

Norna Tesserae

Ustrecha Tesserae

Rose

Chuginadak

Mons

Sitapi Coronae

Nungui

Corona

Tangba

Corona

Hlineu Corona

Chanum Coronae

Adaiah

Darclée

Patera

Zêmaite

Patera

Kulimina

Corona

Hervor

Corona

Xmukane

Corona

Enekeler

Corona

Kastiatsi

Dorsa

Viola

Moore Xenia

Kanik

Nordenflycht

Patera

Destinnová

Patera

Ustinya

Steinbach

Shasenem

Witte

Patera

Azimua

Tholi

Otohime

Tholus

Ajina Fossae

Sinann Vallis

Sopdet 

Tesserae

Achall

Corona

Oanuava Coronae

Zerine

Monoshi

Tholus

PARGA CHASMATA

Mertseger

Mons

Ne Ngam

Mons

Tsovinar

Dorsa

Giltine Tesserae

Wollstonecraft

Norna Tesserae

Ustrecha Tesserae

Rose

Chuginadak

Mons

Sitapi

Coronae

Nungui

Corona

Tangba

Corona

Hlineu

Corona

Chanum Coronae

Adaiah

Darclée

Patera

Zêmaite

Patera

Kulimina

Corona

Achall

Corona

Oanuava Coronae

Hervor

Corona

Xmukane

Corona

Enekeler

Corona

Kastiatsi Dorsa

Viola

Moore

Xenia

Kanik

Nordenflycht

Patera

Destinnová

Patera

Ustinya Steinbach

Shasenem

Witte

Patera

Azimua

Tholi

Otohime

Tholus

Ajina Fossae

Sinann Vallis

Sopdet Tesserae

Mertseger

Mons

Sitapi

Coronae

Nungui

Corona

Tangba

Corona

Hlineu

Corona

Chanum Coronae

Kulimina

Corona

Achall

Corona

Oanuava Coronae

Hervor

Corona

Xmukane

Corona

Enekeler

Corona

Parga Chasmata

HELEN PLANITIA

H E L E N P L A N I T I A

H E L E N P L A N I T I A

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