USGS Science⌕ Search
Home/Archive/USGS

USGS · sim3480

Geologic map of the Aeolis Dorsa Region, Mars

Devon M. Burr·Robert E. Jacobsen·Alexandra Lefort·Rose M. Borden·Samantha E. Peel
View original source ↗Read source document ↗Export metadata ↓

Abstract

The Aeolis Dorsa region of Mars, located just north of the global dichotomy boundary, includes the Aeolis and Zephyria Plana, and a depositional basin between them. This interplana region consists of extensive networks of ridges—the eponymous Aeolis Dorsa—and is interpreted as having formed by topographic inversion of fluvial and alluvial deposits. To the south is a nearly 1-km-deep trough (Aeolis Chaos) and the southern highlands. These elements of the map area compose a landscape of extensive erosional and depositional sedimentary processes. The plana are pervasively abraded into yardangs, and the interplana area shows scattered yardangs superposed on the underlying terrain. The Aeolis Dorsa fluvial deposits are concentrated within and around the margins of the interplana region, exposed and (or) inverted by this pervasive aeolian abrasion. During this period of extensive erosion and deposition, impacts have also redistributed material. The geologic mapping of this region, conducted at 1:500,000 scale to enable depiction of the fine-scale fluvial features, divides the landscape into six unit groups. The highlands units group comprises three units, located in the southwestern map area. These units, having the highest elevation in the map area, consist of mesas surrounded by more gently sloping terrain. The transitional units group, located northeast of the highlands units, includes the Aeolis Chaos, denoted as a chaos terrain unit, and two transitional units, differentiated on the basis of surface texture and relative elevation. The plana units group comprises five units. The oldest unit consists of mesas similar to those of the highlands mesas unit but located about 200 kilometers north of the highlands in Aeolis Planum. Three other plana units, located on the Aeolis and Zephyria Plana, are differentiated on the basis of yardang texture, crosscutting relations, and relative elevations. They are interpreted as abraded sedimentary and (or) volcaniclastic deposits. The fifth plana unit, which crops out in the north corners of the map area, is at low elevation, has numerous small craters, and is interpreted as cratered lava plains. The interplana units group hosts a hummocky unit and a mounds unit, differentiated on the basis of texture and relief. In the Aeolis Dorsa units group, four units are mapped on the basis of dorsa morphology and adjacent textures. Stratigraphic relations indicate a decrease in discharge over time. The crater units group includes a crater unit, found throughout the map area although concentrated within the interplana region, and a crater fill unit that is found within several craters in this interplana region. Based on this mapping, the interpretation of the regional geologic record begins with emplacement of the highlands terrain during the Noachian Period. Emplacement was followed during the Early Hesperian by erosion and redistribution of this high-standing terrain to form the transitional units, and Aeolis Chaos formed after deposition of the other transitional units. The high-standing plana were emplaced and eroded repeatedly throughout the Hesperian and Early Amazonian time, and impact cratering occurred at decreasing crater sizes. The fluvial and alluvial activity that gave rise to the Aeolis Dorsa also extended throughout this time, leaving their diagnostic signature on this region.

Explore related subjects

Scientific Investigations MapReport

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Devon M. Burr, Robert E. Jacobsen, Alexandra Lefort, Rose M. Borden, Samantha E. Peel. 2021-12-14. Geologic map of the Aeolis Dorsa Region, Mars. https://doi.org/10.3133/sim3480

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

KEEP EXPLORING

Related USGS reports

USGS2026

Altitude of the potentiometric surface and depth to water in the Mississippi River Valley alluvial aquifer, spring 2024

Potentiometric-surface and depth-to-water maps for spring 2024 were created for the Mississippi River Valley alluvial aquifer using groundwater-altitude data from 1,151 wells completed in the Mississippi River Valley alluvial aquifer and from the altitude of the top of the water surface in area rivers from 160 U.S. Geological Survey and U.S. Army Corps of Engineers streamgages. The potentiometric-surface and depth-to-water maps for 2024 were created to support investigations to characterize the Mississippi River Valley alluvial aquifer as part of the U.S. Geological Survey Water Availability and Use Science Program. Sufficient data were available to map the potentiometric surface and depth to water of the Mississippi River Valley alluvial aquifer for spring 2024 for about 83 percent of the aquifer area. The potentiometric contours ranged from 0 to 330 feet (ft) above the North American Vertical Datum of 1988. The regional direction of the groundwater gradient was generally to the south-southwest, except in areas of groundwater-altitude depressions, where the groundwater gradient direction was into the depression, and near rivers, where the groundwater gradient direction was either from the aquifer to the river or from the river into the aquifer. Groundwater depressions in the potentiometric-surface map are in the lower one-half of the Cache region and in most of the Grand Prairie and Delta regions. Depth to water by well in the Mississippi River Valley alluvial aquifer in spring 2024 ranged from 0.27 ft above land surface to 145.65 ft below land surface.

Arkansas, Illinois, Kentucky, Louisiana, Mississip↗
USGS2026

Color-Shaded Relief Bathymetry of Lake Chelan, Washington

In 2023, the U.S. Geological Survey (USGS) completed a 3-week field operation in Lake Chelan, Washington, the third deepest lake in the conterminous United States, to acquire sediment cores, high-resolution bathymetry data, and chirp sub-bottom profiles. The high-resolution bathymetry displayed in this map publication was collected using a Norbit Winghead i67-curved array multibeam system; raw data were cleaned and gridded (3 by 3 meters [m]) in the Teledyne CARIS software. In some locations where the slopes of Lake Chelan are near-vertical, multibeam returns were sparse, resulting in artifacts resembling holes that appear as grey dots within the color-shaded bathymetric relief. Although the 2023 bathymetric mapping of Lake Chelan resulted in similar morphometric characteristics to previous hydrographic campaigns (table 1; Kendra and Singleton, 1987; Pelletier and others, 1989), these new data provide a much more detailed understanding of the two physiographic basins that comprise Lake Chelan: the deeper (as deep as 445.8 m [fig. 1]; previously reported as 453 m) and narrower (1–2 kilometers [km] wide) Lucerne Basin to the north, and the shallower (as deep as 127.8 m [fig. 1]), and wider (2–3 km wide) Wapato Basin to the south. With this detailed imaging of Lake Chelan, we find pervasive morphological evidence of slope failure and mass-transport deposits (MTDs) in at least 89 locations within the lake and 63 subaqueous deltas (fig. 2). The deeper Lucerne Basin is dominated by steep slopes and numerous subaqueous deltas fed by steep fluvial catchments, whereas the Wapato Basin contains numerous landslide scarps, scars, and debris aprons along the more gently sloping lake margins, and abundant relict kettle structures from the Pleistocene deglaciation. Lake Chelan’s geomorphic, geophysical, and sediment data contain important records of glacial retreat and advance, regional volcanic eruptions, and earthquakes that generate ground motions severe enough to induce landslides recorded in the sediment as MTDs. The epicenter of the 1872 Washington State Earthquake (M 6.5–7.2; Bakun and others, 2002; Brocher and others, 2017; Sherrod and others, 2021) is along the Spencer Canyon Fault, near the southern end of Lake Chelan. Shaking from this earthquake was strong enough to affect local aquifers, induce liquefaction of unconsolidated sediments, produce large seiches (Brocher and others, 2018), and likely cause landslides within Lake Chelan.

Washington↗
USGS2026

Spectral characteristics and mapping of lithium-rich playas in the Basin and Range Province, western United States

This report presents a comprehensive set of prospectivity maps for lithium in brines located within the playas of the Basin and Range Province of western United States. The prospectivity assessment is based on criteria established in the descriptive deposit model outlined in a previous U.S. Geological Survey report, with a focus on regional remote sensing methodologies. The playas within the study area have been systematically ranked according to several key factors, including size, the presence and abundance of source rocks, vegetation as an indicator of water availability, documented prospects, and data products derived from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor. Notably, the deposits in the playa of Clayton Valley make it stand out as the sole lithium brine-producing playa in the United States. The ASTER sensor provides optimal regional coverage, characterized by a 60-kilometer swath width and unique multispectral capabilities that are not available with other remote sensing instruments. This report and the accompanying maps are intended to serve as resources for further multidisciplinary assessments of lithium or other elements or commodities where prospectivity can be inferred from the presence of proxies such as alteration minerals.

Arizona, Baja California, California, Chihuahua, I↗