The data folder includes:
Explanation of data attributes:
Indicated with an “x” for structures, for which impact evidence has not been reviewed within the context of this database and the structures remain classified according to the source work.
The most common name. Other used names appear in the notes. Craters that are part of a field are named individually, usually the one or several most prominent craters. This approach was adopted to allow precise localization of individual craters and is different from most other databases, which quote names of the whole field. For structures in countries using Latin alphabet, spelling in respective language is adopted. Note that diacritics (a mark added to a letter to indicate a special pronunciation) can be destroyed when saving as .txt file.
Indication of whether the structure is a part of a crater field.
Region, Country, Continent/Ocean
Mostly taken from the referenced literature source, but not always. This may also be derived by the database contributor from Lat/Lon data as those are considered the primary way of the structure location.
Shown in decimal degrees format, where N and E are positive, and S and W are negative. Number of shown digits depends on precision of available data and circumstances. For example, showing a center of a 1-km structure with 1-minute precision is inadequate as the location may end up outside of the structure. Precision of 1 second for an 80-km structure is clearly irrelevant. Beware that underlying number may show many more digits; this is a result of a deg/min/sec conversion to decimal degrees and does not reflect actual precision. When saving in different format or copying and pasting the numbers the formatting may be lost, i.e. zeros at the end will be omitted effectively decreasing precision and irrelevant digits will be shown increasing precision unreasonably.
Original rim-to-rim diameter is preferred. If not available, diameter of observed feature is used. In any case, the diameter should be explained in “Notes”. Please refer to Turtle E. P., Pierazzo E., Collins G. S., Osinski G. R., Melosh H. J., Morgan J. V. and Reimold W. U. (2005) Impact structures: What does crater diameter mean? In Large meteorite impacts III, edited by T. Kenkmann, F. Hörz and A. Deutsch. Geological Society of America Special Paper 384. Boulder, Colorado, USA: Geological Society of America. pp. 1-24.
For some of the structures, original rim-to-rim, present day and limit of deformation diameters are listed.
The age is recorded in original format and with a range of uncertainty. The stratigraphic names are translated in number in the columns “Youngest age”, “Best age”, and “Oldest age” and the note explains how the age was calibrated. For ages indicated with a range, e.g. 100-300 Ma, the “Best age” is left blank as it would be meaningless. “Age uncertainty” is filled in only if explicitly indicated in original data. “Age uncertainty type” shows whether the uncertainty represents 1σ, 2σ, 95% confidence interval, MSWD, stratigraphic range, etc. For cases of approximate ages without an indication of uncertainty an arbitrary 10% uncertainty has been chosen. Note that 2σ and 95% confidence intervals are not necessarily the same.
Representation of age data in several columns allows searching and ranking. Initially, stratigraphic ages were converted to numerical ages for some structures and the original format does not appear in the database. This practice has been later abandoned with a realization that the numerical ages will change according to evolving stratigraphic charts.
The thickness of the rocks (in meters) covering the structure above its rim.
Present water depth
The thickness of water layer (in meters) covering the entire structure. Lakes filling the structures do not count.
This information can be provided with certainty if the answer is “yes”. As one cannot be sure about the negative answer for drilling of many of the structures, “no” should be entered with care.
Indication of the target rocks assuming impact origin of the structures. Target types: W – water, M – metamorphic, I – igneous, S – sedimentary with indexes s – siliciclastic, c – carbonate, e – evaporite. The rock types are presented in the order of decreasing volume in the target (if that is possible to judge).
Target water depth
Indication of the target water depth presented assuming impact origin of the structures.
Indication of the projectile type.
The notes should:
The notes should be kept brief but clear and specific.
Recognition is given to those persons who contributed information to a particular structure in “ready format”. Throwing an abstract at me does not count towards your recognition.