What is the Purpose of this Catalog ?
The following catalog is a resource compiled by Nathalie A. Cabrol and Edmond A. Grin. You are welcome to use it. Martian impact crater lakes are very special places that will allow to answer many of the questions raised by the Mars Surveyor Program:
reconstruction of the hydrogeologic history of Mars
reconstruction of climate. Lakes, and especially when they are confined like in craters, are hypersensitive to changes in their local, regional, and global environment
unique environment for life, with in addition, a temporary (up to 100,000 years for large craters) source of heat that could have generated hydrothermal systems
Favorable environment for the preservation of fossils
Great excavators and collectors of material from various geologic origins and ages
Paleolakes in Martian impact craters are likely to provide the among the most favorable exploration sites, both for automated and manned missions. You may find your favorite site in this catalog if, like us, you are convinced that impact crater lakes are places to go. The catalog is here to help your research. The only thing we ask Edmond and I, is for you to be kind enough to acknowledge the source of the data you are using when you are writing papers or using this material for presentation.
The Catalog
This catalog provides information about possible paleolakes in impact craters on Mars. They are characterized at global scale using the Viking Orbiter data. Because of the resolution and current lack of better data for the floor, only craters supplied by channels and fluvial valley networks were considered. Therefore, this catalog is voluntarily omitting all other paleolakes in craters that could have been formed by groundwater drainage only. Already, Mars Global Surveyor better resolution and TES instrument are revealing interesting candidates falling in this category. With time, we will update and complete this catalog with the MGS data, adding the new discoveries, spectral information and limnologic and bathymetric models.
We identified 179 paleolakes in impact structures formed by surface influx of valley networks that can be classified in three different fluvio-lacustrine systems: closed, open, and lake chain systems. The hydrogeologic implications for each of the three systems, and their significance in term of duration of fluvio-lacustrine activity are discussed in a paper currently under review at Icarus (for reference, go back to papers.
For now, we are posting the catalog containing the areographical, physical, and physiographical data for each of the studied impact crater lake, with the description of the sedimentary structures observed. Later I will add comments and scientific discussions about what we see can mean. In the mean time, we provide you the basics to use the catalog.
The User's Manual...
Everything is almost self-explanatory. The tables contain 17 columns:
Location, physiography and Classification
- No is the catalog number of the impact crater lake (ICL)
- Lat. is the latitude of the ICL
- long. is the longitude of the ICL
- MC is the regional subquadrangle of Mars where the ICL is observed
- Diam. is the diameter of the crater (both for the rim and the floor)
- Depth is the depth (measured with the shadow-length) from the top of the rim to the floor of the crater
- Basin Class. We identified 3 classes of basins: closed (no spillway visible), open when one or several spillways are observed, and lake chain when one or a series of channels and/or fluvial valley networks crossed and filled several impact craters in a row, leaving indicators of the formation of several ICLs
- Channel type Type of channel entering the impact crater
The Morphologic Indicators
- Delta a delta has been formed at the outlet of the channel in the crater
- Ter. Sedimentary terraces are observed in the crater. We explain how we determine that the terraces are sedimentary in origin here
- Lay Layering is observed in the sediment
- ASD Aqueous sedimentary deposits observed
- Ev Possible evaporite deposits. To learn more about this subject, read the work of....We show you several examples here...
- Sh Traces of plausible shoreline are visible
- M Mounds.They are usually rounded and close to the shoreline. They can be eroded sedimentary deposits and/or perhaps tufa towers as proposed by Kempe and Kazmierzak (1997) in Planetary and Space Science
- CP Stands for central peak. We also put this information in the catalog because it is a good indicator of the erosion stage first, and second because of the important part played by the heat transfered through the central peak in the formation of hydrothermal systems. On Earth, hydrothermal springs are well-known to be favorable sites for the concetration of living organisms (see works by Horton Newsom)
Last information: there are black and white boxes in the columns. When they are black, the feature is observed. When they are white, there are plausible indicators that the feature is present. When there is no box, the feature is not observed. We hope it that this catalog will be a useful tool. Let us know when you are using it. Thanks.
Catalog of Martian Impact Crater Lakes
