How to Use EarthChem

EarthChem Portal

Setting constraints on sample selection

You can set any combination of the following:

1. Reference and Keyword Search: Use this query parameter if you know the specific year, author, journal, or keyword that contains the data you are looking for.
2. Location: The location query allows you to retrieve data by selecting an area on a map by defining a polygon, inputting specific geospatial coordinates, or by browsing geographic locations defined in the EarthChem Gazetteer.
3. Rock Type:  Search by material type and associated rock types using names provided in the publication or by TAS diagram classification.
4. Chemistry:  Query the global dataset for specific chemical items and range of values. 
5. Glossary: Click on the left-hand menu to search by glossary item or define your own. Simply register or login to create a reusable query.
6. Material:  Choose between bulk composition, whole rock/rock, glass/groundmass, or glass/inclusion

Data Output

You can view data several ways.  To change output option hit the 'back' button on your browser and select another output.

1. Data Access - Download data in and HTML table, Text file, or XLS Spreadsheet. Options allow you to choose which chemical items you want displayed.
2. Metadata - Choose to view a reference list or  a quickly rendered HTML table of samples. Output columns are pre-determined to commonly displayed output.
3. Visualization Tools Choose to explore data in various formats. including TAS Diagrams, animation (for samples with age data), Harker diagrams, XYZ plots, dynamic and static maps, or Google Earth kml output.  For all options except the the static map and Google earth output, you can activate data points by scrolling down and clicking "Datapoints link to individual sample data?" followed by clicking the "Plot" button.  This allows you to view the samples metadata as it appears in its native database".  See below for more details on visualization tools. 

• TAS and Harker Diagram Buttons:  Click on these buttons to view sample data plotted on a Total Alkali vs. Silica (TAS) diagram subdivided with the classification of Streckeisen et al. (Le Maitre, ed., 2002) or to view (Harker) plots of the compositional variation of Major Oxides vs. Silica.  You may modify the size, number of plots, and symbols displayed by using tools at the bottom of the Harker diagram page. 
• Static and Dynamic Maps - To view samples on a map click on Static Map. Use the Dynamic map if you would like to click on a location and to view a sample information page. However, the dynamic map works best with queries of than 100 samples.
• Plotting Tools -  Create X-Y-Z plots of elements or ratios from your queried data. Explore multiple design options!
• Google Earth - Outputs a kml file viewable in Google Earth.  Sample locations link to the native databases and are color-coded by database of origin.

Citation Search

You may view how many times data associated with a specific author or publication have been downloaded by unique IP addresses by clicking on the Citation Search left-hand menu item. Simply enter reference information to obtain the number of downloads. The details button next to each reference provides additional information on the number of downloads per IP address and dates when the downloads occurred.

Glossary

Query the database by exploring predefined parameters or create your own!  Simply register by scrolling down the Glossary menu on the left hand side of the screen.

Deep Lithosphere Petrological Dataset

Setting constraints on a sample selection

The database contains chemical data for xenolith and host rock samples including volcanic, intrusive and metamorphic and mantle rocks, and rocks from different tectonic settings.

To query the database for chemical values, you first need to select samples in which you are interested. The following criteria can be used (you can use one criteria or a combination of criteria):

• LATITUDE/LONGITUDE: Enter latitude and/or longitude of the geographical area you are interested in. Enter the Northern and Southern bounding latitudes (latitudes on the southern hemisphere need to be entered as negative values, e.g. 9.6°S = -9.6) and the Western and Eastern longitudes (Western longitudes need to be entered as negative values, e.g. 112°W = -112).
   
• LOCATION: Use geographical names define a specific geographical area for your sample selection. Geographical names are used on various regional scales ranging from name of a volcanic province to volcano type or the name of an orogenic belt.
   
• TECTONIC SETTING: Use this criterion if you are interested in samples from one or more specific tectonic settings such as 'INTRAPLATE_CRATON', 'CONVERGENT_MARGIN', or 'CONTINENTAL_RIFT'.
   
• SAMPLE CHARACTERISTICS: You can define your sample selection by rock type (e.g. 'basaltic', 'alkaline', 'xenolith'), by degree of alteration*. When you click on a rock type, you will see a list rock classes in the selection box. It is important to note that the classification of samples into these 'rock classes' is based on information provided in publications and is NOT done by EarthChem.
  Note: Information on degree of alteration is provided only for a minority of samples in EarthChem due to lack of this information in publications. Selecting only 'fresh' samples will ensure that the data you get were actually measured on fresh samples, but you might miss data for fresh samples just because there was no information on alteration in the data publication.
   
• PUBLICATION INFORMATION: The option 'Set Publication Information' allows you to find specific publications in the Deep Lithosphere dataset and view and download data tables from the publication* (click on 'data tables' in the list of references that is returned when you submit a query for publications by author(s), year(s), keyword(s), etc.). Once you see a list of references, you can select any of these to define the group of samples for which you want data by clicking on 'APPLY'. Applying selected references to your sample search will allow you to find all chemical data for these samples available from multiple references. Note: The data tables contain only original values, any referenced values can only be found in the original publication.
   
• DATA AVAILABILITY: Use a query by data availability if you are looking for data from samples for which specific data types have been published. For example, if you are interested to get data for only those samples for which major elements AND olivine analyses are available, you click on the appropriate check boxes here.
   
• DATABASE VERSION: Querying by database version allows you to get only those data that were added during a specific update of the database. This is helpful if for example you are working with large spreadsheets that you generated through a query to the database that you adjusted and edited to fit your needs. You do not have to re-generate the entire spreadsheet, you can just append data that were added to the Deep Lithosphere dataset after your last download.
   
• SAMPLE NAME: You can find samples by the name that is reported in the publication ('ALIAS'), or by the Deep Lithosphere unique sample identifier. As many names in publications are non-unique (e.g. D5-1), you will often get multiple results. You need to check the sample information by clicking on the sample identifier to decide which sample is the correct one.
   

Downloading: Pre-Compiled Data vs. Individual Analyses

Individual analyses

This option will return a data table that contains all analytical values available for the samples and for the chemical parameters you selected organized by reference and method. This means that each individual row of the result table will contain only those analytical values for a sample that were analyzed with the same method and reported in same reference.

If you select 'Individual Analyses', you will get a table that lists all analyses available for the samples and for the chemical items you selected organized by reference and method. If multiple measurements have been made for a certain chemical item on the same sample (e.g. Nb measured by different methods and published in different papers), they will all be listed in the table. One row in the data table will only contain values from one publication and only data acquired by the same method. A table with individual analyses will generally report data for the same sample in multiple rows.

Pre-compiled

This option will return a data table with only one row for each sample that contains a compilation of analytical values measured by different methods or reported in different references. If multiple values for the same chemical parameter exist, one of the values is selected on the basis of rules that we established (see below).

Example: You selected to get major elements, Nb, Rb, and Sr concentrations , and Sr and Nd isotope ratios for samples A,B, and C. Major elements analyzed by XRF and wet chemistry for these samples were published in reference 1, the trace elements analyzed by ICP-MS in reference 2, isotope ratios by mass spectrometry and Sr and Rb by isotope dilution MS in reference 3.

Rules of Data Selection for Pre-Compilation

For isotope ratios:

1. Publication year is compared. The latest value has the highest priority
2. If there is more than one value published in the latest year, standard deviation is used as criteria.

For major elements, rare earth elements and other trace elements:

1. Method: choose the values with highest method priority.
2. If there is more than one value done by the same method (and which has the highest priority among all analyses for that element of that sample), then publication year is compared. The latest value has the highest priority

Method: listed below with priority from high to low.

Major elements:

• XRF: X-RAY FLUORESCENCE
• DCP: DIRECT CURRENT PLASMA
• WET: WET CHEMISTRY
• EMP: ELECTRON MICROPROBE
• ES: EMISSION SPECTROMETRY
• Other

Rare earth elements:

• MS-ID: ISOTOPE DILUTION MASS SPECTROMETRY
• MS: MASS SPECTROMETRY
• ICPMS: INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY
• DCP: DIRECT CURRENT PLASMA
• SSMS: SPARC SOURCE MASS SPECTROMETRY
• INAA: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS
• Other

Other trace elements:

• MS-ID: ISOTOPE DILUTION MASS SPECTROMETRY
• MS: MASS SPECTROMETRY
• ICPMS: INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY
• SSMS: SPARC SOURCE MASS SPECTROMETRY
• XRF: X-RAY FLUORESCENCE
• DCP: DIRECT CURRENT PLASMA
• INAA: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS
• AAS: ATOMIC ABSORPTION
• Other