Search USGS⌕ Search
Home/Archive/USGS

USGS · i2637

Geologic map of the Sappho Patera Quadrangle (V-20), Venus

George E. McGill
View original source ↗Read source document ↗Export metadata ↓

Abstract

The Sappho Patera quadrangle (V–20) of Venus is bounded by 0° and 30° East longitude, 0° and 25° North latitude. It is one of 62 quadrangles covering the entire planet at a scale of 1:5,000,000. The quadrangle derives its name from Sappho Patera, a large rimmed depression (diameter about 225 km) lying on top of a shield-shaped mountain named Irnini Mons. Sappho, a noted Greek poet born about 612 B.C., spent most of her life on the island of Lesbos. All of her works were burned in 1073 by order of ecclesiastical authorities in Rome and Constantinople. What little survives was discovered in 1897 as parts of papier mâché coffins in the Fayum (Durant, 1939). The Sappho Patera quadrangle includes the central portion of Eistla Regio, an elongated, moderately elevated (relief ~1 km) region extending for about 7,500 km west-northwestward from the west end of Aphrodite Terra. It is generally interpreted to be the surface manifestation of one or more mantle plumes (Phillips and Malin, 1983; Stofan and Saunders, 1990; Kiefer and Hager, 1991; Senske and others, 1992; Grimm and Phillips, 1992; Solomon and others, 1992). Eistla Regio is dominated by several large volcanic features. All or parts of four of these occur within the Sappho Patera quadrangle: the eastern flank of Gula Mons, Irnini Mons, Anala Mons, and Kali Mons. The quadrangle also includes eight named coronae: Nehalennia, Sunrta, Libera, Belet-Ili, Gaia, Asomama, Rabzhima, and Changko. A major rift extends from Gula Mons in the northwestern corner of the quadrangle to Libera Corona near the east border. East of Irnini and Anala Montes this rift is named Guor Linea; west of the montes it is named Virtus Linea. In addition to these major features, the Sappho Patera quadrangle includes numerous smaller volcanic flows and constructs, several unnamed coronae and corona-like features, a complex array of faults, fractures, and wrinkle ridges, and extensive plains that are continuous with the regional plains that constitute about 80% of the surface of Venus (Masursky and others, 1980). This area is geologically interesting because it contains examples of most globally important types of features and deposits and is an excellent area to study the temporal and genetic relations among plains, rifts, coronae, and large shield volcanoes. The temporal relations displayed in this quadrangle can provide useful constraints on models for venusian tectonic style (McGill, 1994b).

Explore related subjects

IMAPReport

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

George E. McGill. 2000. Geologic map of the Sappho Patera Quadrangle (V-20), Venus. https://doi.org/10.3133/i2637

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2013

Coastal-change and glaciological map of the Amery Ice Shelf area, Antarctica: 1961–2004

Reduction in the area and volume of Earth’s two polar ice sheets is intricately linked to changes in global climate and to the resulting rise in sea level. Measurement of changes in area and mass balance of the Antarctic ice sheet was given a very high priority in recommendations by the Polar Research Board of the National Research Council. On the basis of these recommendations, the U.S. Geological Survey used its archive of satellite images to document changes in the cryospheric coastline of Antarctica and analyze the glaciological features of the coastal regions. Amery Ice Shelf, lying between 67.5° and 75° East longitude and 68.5° and 73.2° South latitude, is the largest ice shelf in East Antarctica. The latest measurements of the area of the ice shelf range between 62,620 and 71,260 square kilometers. The ice shelf is fed primarily by Lambert, Mellor, and Fisher Glaciers; its thickness ranges from 3,000 meters in the center of the grounding line to less than 300 meters at the ice front. Lambert Glacier is considered to be the largest glacier in the world, and its drainage basin is more than 1 million square kilometers in area. It is possible to see some coastal change on the outlet glaciers along the coast, but most of the noticeable change occurs on the Amery Ice Shelf front.

IMAP↗
USGS2010

Coastal-change and glaciological map of the Ross Island area, Antarctica

Reduction in the area and volume of Earth?s two polar ice sheets is intricately linked to changes in global climate and to the resulting rise in sea level. Measurement of changes in area and mass balance of the Antarctic ice sheet was given a very high priority in recommendations by the Polar Research Board of the National Research Council. On the basis of these recommendations, the U.S. Geological Survey used its archive of satellite images to document changes in the cryospheric coastline of Antarctica and analyze the glaciological features of the coastal regions. The Ross Island area map is bounded by long 141? E. and 175? E. and by lat 76? S. and 81? S. The map covers the part of southern Victoria Land that includes the northwestern Ross Ice Shelf, the McMurdo Ice Shelf, part of the polar plateau and Transantarctic Mountains, the McMurdo Dry Valleys, northernmost Shackleton Coast, Hillary Coast, the southern part of Scott Coast, and Ross Island. Little noticeable change has occurred in the ice fronts on the map, so the focus is on glaciological features. In the western part of the map area, the polar plateau of East Antarctica, once thought to be a featureless region, has subtle wavelike surface forms (megadunes) and flow traces of glaciers that originate far inland and extend to the coast or into the Ross Ice Shelf. There are numerous outlet glaciers. Glaciers drain into the McMurdo Dry Valleys, through the Transantarctic Mountains into the Ross Sea, or into the Ross Ice Shelf. Byrd Glacier is the largest. West of the Transantarctic Mountains are areas of blue ice, readily identifiable on Landsat images, that have been determined to be prime areas for finding meteorites. Three subglacial lakes have been identified in the map area. Because McMurdo Station, the main U.S. scientific research station in Antarctica, is located on Ross Island in the map area, many of these and other features in the area have been studied extensively. The paper version of this map is available for purchase from the USGS Store.

IMAP↗
USGS2009

Coastal-Change and Glaciological Map of the Palmer Land Area, Antarctica: 1947-2009

Reduction in the area and volume of the two polar ice sheets is intricately linked to changes in global climate, and the resulting rise in sea level could severely impact the densely populated coastal regions on Earth. Antarctica is Earth's largest reservoir of glacial ice. Melting of the West Antarctic part alone of the Antarctic ice sheet would cause a sea-level rise of approximately 6 meters (m), and the potential sea-level rise after melting of the entire Antarctic ice sheet is estimated to be 65 m (Lythe and others, 2001) to 73 m (Williams and Hall, 1993). The mass balance (the net volumetric gain or loss) of the Antarctic ice sheet is highly complex, responding differently to different climatic and other conditions in each region (Vaughan, 2005). In a review paper, Rignot and Thomas (2002) concluded that the West Antarctic ice sheet is probably becoming thinner overall; although it is known to be thickening in the west, it is thinning in the north. The mass balance of the East Antarctic ice sheet is thought by Davis and others (2005) to be positive on the basis of the change in satellite-altimetry measurements made between 1992 and 2003. Measurement of changes in area and mass balance of the Antarctic ice sheet was given a very high priority in recommendations by the Polar Research Board of the National Research Council (1986), in subsequent recommendations by the Scientific Committee on Antarctic Research (SCAR) (1989, 1993), and by the National Science Foundation's (1990) Division of Polar Programs. On the basis of these recommendations, the U.S. Geological Survey (USGS) decided that the archive of early 1970s Landsat 1, 2, and 3 Multispectral Scanner (MSS) images of Antarctica and the subsequent repeat coverage made possible with Landsat and other satellite images provided an excellent means of documenting changes in the cryospheric coastline of Antarctica (Ferrigno and Gould, 1987). The availability of this information provided the impetus for carrying out a comprehensive analysis of the glaciological features of the coastal regions and changes in ice fronts of Antarctica (Swithinbank, 1988; Williams and Ferrigno, 1988). The project was later modified to include Landsat 4 and 5 MSS and Thematic Mapper (TM) images (and in some areas Landsat 7 Enhanced Thematic Mapper Plus (ETM+) images), RADARSAT images, aerial photography, and other data where available, to compare changes that occurred during a 20- to 25- or 30-year time interval (or longer where data were available, as in the Antarctic Peninsula). The results of the analysis are being used to produce a digital database and a series of USGS Geologic Investigations Series Maps (I-2600) (Williams and others, 1995; Swithinbank and others, 2003a,b, 2004; Ferrigno and others, 2002, 2005, 2006, 2007, 2008, and in press; and Williams and Ferrigno, 2005) (available online at http://www.glaciers.er.usgs.gov).

IMAP↗