Windmill Islands 1:10000 Geological Sampling GIS Dataset

Full description

This is a data set of locations at which geological samples were collected at the Windmill Islands.
The data is provided as a point shapefile. Attributes of the points include sample number, sample type, lithology and chemical analyses.
See the Quality field for further information.

Lineage

Progress Code: completed

Statement: Lineage The sources of information on geological samples is as follows: 1. Blight, D.F. 1975. The Metamorphic Geology of the Windmill Islands and adjacent coastal areas. PhD thesis. University of Adelaide. This includes a map showing the location of samples taken. 2. Blight, D.F. and Oliver, R.L. 1977. The Metamorphic Geology of the Windmill Islands, Antarctica: A Preliminary Account. Journal of the Geological Society of Australia, Vol. 24, Pt 5, pp 239-262. This contains the results of the analyses carried out on the samples referred to above. 3. Information supplied by Assoc. Prof. Richard Price. Professor Price is currently at: School of Earth Sciences La Trobe University Kingsbury Drive Bundoora, Victoria 3083 Positional Accuracy The positional accuracy of the sample locations is, at worst, about 150 metres. The samples have been positioned by two methods: In the case of Dr Blight's samples, the locations were screen-digitised from the map showing the locations of samples. In the case of Prof. Price's samples, the sample locations are given with a 6-figure grid reference and a description of their locations with respect to prominent features. Where the locations of all samples are within 100 m of a rock outcrop, the sample location has been fitted to that outcrop. Where the location is greater than 100 m, then the sample location is left where it is. Minor adjustments were made to match rock type in a few cases but in general, no adjustment was made. It should be noted that rock outcrops change from one year to the next depending on the amount of snow or the extent of summer melt. Attribute accuracy The attributes are exactly those published and as supplied. Further information on the attributes The following abbreviations have been used: ANALYSTS DFB and RLO = DF Blight and RL Oliver RP = R Price SAMPLE_TYPE GEOCHEM = Sample for geochemistry HAND_SPEC = Hand specimen Note. Geochemistry samples tend to be larger than hand specimens. The abbreviations used in the analyses are the International Standard abbreviations of the Periodic Table of Elements except that upper case is used throughout. The major elements are in percentage of mass, the minor and trace elements are in ppm. The analyses are whole rock analyses. Some fields, such as FE2O3 have a character field in addition to the numerical field. This is to allow the use of a "less than" symbol. Where a "less than" sign appears in a character field, the value has been shown as not determined in the numerical field. Where the value in a field has not been determined, a negative number has been used. This is -999, -9.99 or -9.999 as required to fit the type of field. Character fields are designated with the suffix _CHAR. Ratios. K_TO_RB_RATIO. In all analyses this is calculated as: K20 % x 10 000/RB ppm RB_TO_SR_RATIO. In all analyses this is calculated as: RB ppm/SR ppm TH_X_10000_TO_K. In all analyses this is calculated as: TH ppm/K20 % K_TO_PB_RATIO. In all analyses this is calculated as: K20 % x 10 000/PB ppm Note Blight sample number 335-21. TH_X_10000_TO_K ratio (29.51) appears to have been calculated incorrectly. It is believed that this value should be: 8.49. Blight sample number 335-402. TH_X_10000_TO_K ratio (2.6). In Arc/Info this has been ascribed the value of 2.60. The correct value to two decimal places should be 2.61. It is believed that three significant figures are not, however, justified in this instance. In a number of cases the results have been presented to varying numbers of decimal places. Arc/Info has ascribed two decimal places in most of the floating point fields. The character fields, however, preserve the original values as quoted by the authors. Logical consistency All points are labelled and have attribute data attached. Completeness The data presented here are all the data supplied. Other collections of samples are known to exist but are not included here as information has not been supplied by the field geologists.