Introduction

Identify and prioritize exploration targets with geochemical surface methods

UpDeep project focuses on developing low environmental impact geochemical exploration service that specializes on surface geochemical techniques. The UpDeep surface geochemical concept aids exploration industry to identify and prioritize potential exploration targets by reducing time and cost while improving reliability in target detection. The surface geochemical exploration is based on analysing trace amounts of metals or other elements and soil hydrocarbons in plants and soil horizons to discover deep buried mineralisations.

UpDeep Online Statistics Tool (Figure 1) is a JavaScript based on a web map application. The purpose of using the UpDeep Online Statistics Tool for the surface geochemical data producer/interpreter is to be able to compare concentration levels in person’s own data to concentrations in the similar data stored in the database of the UpDeep Online Statistics Tool. Relevant metadata is stored in the database such that data can be searched by location, sampling media, sample pretreatment and dissolution type.

The database of the UpDeep Online Statistics Tool is open for geoscientists across the world to download their own data into the database and thus contribute to the common good and understanding of the surface geochemical data. The application enables extracting existing surface geochemical data from the underlying DB and plot the geochemical data in a statistical graph. The UpDeep Online Statistics Tool is hosted on a GTK server.

The first version of the UpDeep Online Statistics Tool is currently containing surface geochemical data only from Finland, collected in a project called UltraLIM (Ultra low impact exploration methods in the sub-arctic, 2013-2015). There is also surface geochemical data from Greenland and France colledted in UpDeep project. However, the UpDeep Online Statistics Tool is open and free for everyone. The data is distributed under a Creative Commons 4.0 license (GTK, 2018) There is a possibility for users to send their own geochemical data to the UpDeep Online Statistics Tool DB. GTK personel will check the data first and then imports the data to the database. At this stage, the DB consists sample data from plants and soil and data about their concentration levels from eight study areas in Finland. PPM (parts-per million) is used as a common unit for every element to handle the element concentrations the uniform way.

The UpDeep Online Statistics Tool is developed with JavaScript scripting language. This web application is using ArcGIS API for JavaScript, cmv.io and plotly.js libraries and frameworks developing user interface for viewing, searching, using and downloading GIS based geochemical data. The ArcGIS for Server is used as a server software to create the GIS interfaces for serving spatial data used in the web application.

The UpDeep Online Statistics Tool can be used in two phases of a surface geochemical survey:

1) Sampling planning the UpDeep Online Statistics Tool could be used to see existing surface geochemical data collected in similar environments, similar sampling materials and similar deposit types to aid the sampling planning in the user’s current case study. This could help the user to choose an appropriate sample material, sample pretreatment and extraction e.g. when it is suspected the concentration levels may be under the detection limit (<LDL). The current DB is very limited to fully utilize the tool for this purpose. However, it is hoped geochemists/geologists would be willing to share their own data by importing it to the UpDeep Online Statistics Tool. This way information in the DB will increase.

2) Data analysis and interpretation to compare concentration levels in the user’s own data to existing data in the The UpDeep Online Statistics Tool DB. The results of the UltraLIM study (see Middleton et al. 2020) demonstrated that the overall concentration levels of samples may give an indication of an existing underlying mineralization or a mineralized region. In this case, the user would want to compare their own concentration levels to ones that are collected from the same geochemical sampling media and analysed with the similar or the same sample pretreatment and laboratory analytics.

1 Tools

There are two tools in this web application. Tools or widgets are client side applications with a small or limited functionality. Search widget is for searching suitable or wanted points on the map for data downloading or for statistical presentation of fetched data.

1.1 Table of contents

Layers or Table of content widget (Figure 1) is used for handling layers in the map window.

1.1.1 Layers Swipe

Depending on a layer there are some possibilities to modify map view concerning a layer's visibility. By clicking the icon, it is possible for example to change transparency of the layer or to use Layer Swipe (Figure 2) option. Layer Swipe allows fading of the layer via a slider control.

1.1.2 Identify features

User can view information about plants and soils samples with an identify tool (function). Information popup window (Figure 3) opens when user clicks a sample point on the map. The identify tool works with Plant samples and Soil samples layers.

1.2 Search

The search widget (Figure 4 Search window) is the key component in the UpDeep Online Statistics Tool. User can search data by attributes or by selecting features based on location by using a spatial tool. Optionally, the user can use both of these options together. In any case, the user firstly has to select a layer (see red arrow). Every forthcoming query is made from the selected layer

1.2.1 Search by attributes

There are three to eight predefined attributes available for searching features depending on selected layer. Predefined attributes are linked to the selected layer. If the layer is changed then the attributes will be changed as well. These attributes are mostly used when selecting proper sample points. Selection criteria varies when selecting plant samples or soil samples as a selected layer. When searching plant samples, user can modify the query by selecting the site, analysis method, plant, plant organ, year, mineralization exists, mineralization size, geological deposit type and deposit depth (m) for geological deposit. Analysis method is the only mandatory attributes when selecting attributes for the query.

When searching soil samples, user can modify the query by selecting the site, analysis method, year, soil horizon, mineralization exists, mineralization size, geological deposit type and deposit depth (m) for geological deposit.

After clicking on the Search button the results table opens on the map window. User can create a statistical boxplot graph based on search results data (check references for figures, update in desktop word). Results can also be downloaded in Excel format.

It is possible to create an advanced SQL query for searching the surface geochemical data. After the Switch to Advanced Search button is pressed, a window for creating SQL query open (Figure 5). With operators 'AND' and 'OR' user can create different kinds of conditions to query samples data. When creating query with multiple conditions, the selected operator button turns dark blue in color. Green Add rule button creates a new condition to the query and the red Delete button removes the current condition from the query.

1.2.2 Search by location

User can search sample points based on location on the map. After choosing a target layer Selecting points By Shape tab (Figure 6) gives seven selection criteria to select features on the map. Select by rectangle, circle, point, line, freehand line, polygon and freehand polygon are the options for selecting tool. User can also set a buffer around the selected area.

2 Results

Search button in the bottom of the Search widget window runs the query. If the request is successful function will generate the result table (Figure 7) on the map window. Search function highlights the results samples from the query on the map. At first only basic metadata can be seen, but user can select and view more columns by clicking the small button in the right hand side of the grid. Query is limited to one thousand features.

2.1 Extract data

By pressing the Export button the data can be downloaded to the user own computer (Figure 8). For now the Excel format is the only format for downloading data. Excel files contains the whole results table data, not only what is visible on the table.

2.2 Boxplots

Statistical boxplot graphs can be drawn based on the data query. It is possible to create a boxplot based on multiple elements at a time. Elements will be chosen in the Analyze filters window (Figure 9). The X-axis of the box plot can be in concentrations or logarithm of the concentrations. In the Analyze filters window it is possible to choose logarithmical calculation for statistical graph.

After the Create Boxplot button is pressed opens Charts window (Figure 10). Boxplot chart is created with plotly.js JavaScript library. Charts are generated so that for every chosen element will be generated own boxplot chart.

By selecting Log-scale checkbox boxplots are generated by using common logarithm. If log-scale is used then the title of the chart contains minimum and maximum values of the original data (Figure 11).

2.3 Chart Studio

Charts window offers possibilities to download the boxplot graph as a png image or to view and edit data in the Chart Studio. Chart Studio is a free web-based component by plotly.js library. Both of these possibilities can be found in the top right hand corner when the mouse pointer is located on the boxplot graph (Figure 12).