Online Links:
Range of values | |
---|---|
Minimum: | 1906 |
Maximum: | 100799 |
Value | Definition |
---|---|
DGGS | Data from Alaska Division of Geological and Geophysical Surveys (ADGGS) geochemical database, located http://www.dggs.alaska.gov/webgeochem. |
PR_LIT | Data was obtained from either peer-reviewed literature or is unpublished USGS data. |
USGS | Data was obtained from the U.S. Geological Survey Alaska Geochemical Database, version 2.0. Data is available at http://mrdata.usgs.gov/agdb/ |
Range of values | |
---|---|
Minimum: | 51.25 |
Maximum: | 70.20583 |
Units: | degrees |
Range of values | |
---|---|
Minimum: | -179.11667 |
Maximum: | 179.45 |
Units: | degrees |
Range of values | |
---|---|
Minimum: | -21.4 |
Maximum: | 99.11111 |
Units: | weight percent |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 715.97213 |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 715.97213 |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 0.99919 |
Range of values | |
---|---|
Minimum: | -0.87373 |
Maximum: | 0.38882 |
Range of values | |
---|---|
Minimum: | -48.78075 |
Maximum: | 30.40781 |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 68.32067 |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 40 |
Value | Definition |
---|---|
<null> | Not determined |
Ferroan | Fe_no_displ > 0. There are also samples in which Fe_no_displ is null included in Ferroan, because MgO was extremely low (extremely fractionated), that Fe_no could not be calculated. These samples are judged to be ferroan because Fe would be about 1.0. |
Magnesian | Fe_no_displ <= 0 |
Value | Definition |
---|---|
<null> | insufficient data to determine |
calcic | MALI_displ < -2.5 |
alk-calc | -2.5 < MALI_displ < 0 |
calc-alk | 0 < MALI_displ < 1.5 |
alkalic | MALI_displ > 1.5 |
Value | Definition |
---|---|
<null> | insufficient data to determine |
peraluminous | ANK > 1.2 and ASI >= 1.1 |
metaluminous | ANK > 1.2 and ASI < 1.1 |
peralkaline | ANK <= 1.2 |
Erin Todd and Nora Shew, USGS
Feature class all_igneous_ratios is used to identify permissive rock types for REE deposits and Sn-W-Mo deposits. The ratios for the aluminum saturation index, ASI, (Al/[Ca-1.67xP)+Na+K], and ANK, Al/[Na+K], allow for the differentiation between peraluminous, metaluminous, and peralkaline rocks. Trace element concentration ratios Nb/Y and Ga/Al can distinguish alkaline and subalkaline igneous rocks. Also, the modified alkali-lime index, MALI, (Na2O+K2O-CaO), and Fe_no, FeO/[FeO+MgO], can used to distinguish alkaline vs calcic, and ferroan vs magnesian rocks.
Are there legal restrictions on access or use of the data?Access_Constraints: None
Use_Constraints:None. Users are advised to read the publication text and metadata to understand the appropriate use and data limitations.
This publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
Data format: | ArcGIS geodatabase |
---|---|
Network links: |
http://dx.doi.org/10.3133/ofr20161191 |