Marker horizon depth measurements at each Surface Elevation Table (SET) site. Marker horizons are commonly used in conjunction with the SET. Marker horizons measure vertical accretion which predominantly incorporates surface processes.
Marker horizons are a thin layer of feldspar. Marker horizon depths are measured each spring and fall. Each SET site has one marker horizon; three replicate cores are taken from each horizon during samplings. The depth of sediment accreted above the feldspar marker is measured on 4 side of the rectangular core using calipers. Measurements are made to the top of the feldspar layer. Cores are replaced after the measurements have been made. The values recorded in the data file represent sediment above marker horizon at the time of measurement. It is important to note that different cores are taken during each measurement, thus core A on date “X” can not be to compared to core A on date “Y”. For comparisons over time, measurements should be averaged over all “cores” and “replicates” for each individual SET. Cores or “Plugs” are taken from each horizon using a kitchen knife. This method is not ideal for several of our more wet sites. There is a high probability of erroneous measurement in sites that are very wet. We are working on a better method for sampling.
For more information on SET and Marker Horizons see: http://www.pwrc.usgs.gov/set
Latitude and Longitude reported as decimal degrees in the NAD 83 Datum.
Elevation is reported as NAVD 88, orthometric height (meters), and is currently an unprocessed measurement of the SET insert pipe. For more information please contact Aaron Strong (email@example.com). Locations for Levine’s SET 2-3 are not available at this time.
Site SET # Marker Horizon LAT LONG Elevation Marsh Type Dominant Vegetation
Holy Island 1 04/30/03 42.73118814 -70.82625404 1.36 Low Spartina alterniflora (short)
Holy Island 2 04/30/03 42.7305772 -70.82672061 1.45 Transition Spartina alterniflora (short)
Holy Island 3 04/30/03 42.73009768 -70.82693638 1.69 High Spartina patens
Laws Point 1 12/7/2000 42.73157969 -70.84149472 1.39 Low Spartina alterniflora (short)
Laws Point 2 12/7/2000 42.7312578 -70.84219796 1.40 Transition Spartina alterniflora (short)
Laws Point 3 12/7/2000 42.73069447 -70.84275403 1.70 High Spartina patens
Levine’s 1 12/7/2000 42.72733649 -70.85228593 1.68 Low Spartina patens
Levine’s 2 12/7/2000 High Spartina alterniflora (short)
Levine’s 3 12/7/2000 High Spartina patens
Morris Island 1 05/01/03 42.72912254 -70.83472098 1.18 Low Spartina alterniflora (tall)
Morris Island 2 05/01/03 42.72923966 -70.83544812 1.07 Low Spartina alterniflora (tall)
Morris Island 3 05/01/03 42.72942128 -70.836324 1.13 Low Spartina alterniflora (tall)
Sampling your marker horizons http://www.pwrc.usgs.gov/set/readmarkers.html
Version 01, initial Excel EML file
Version 02, Updated data through Fall 2009 12/1/2009
Version 03: January 19, 2012, updated data and metadata through Spring 2011. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 1/18/12 4:51 PM for QA/QC to EML 2.1.004).
Version 04: February 9, 2016, updated data and metadata through Spring 2015 to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007_Jan2015.xlsm 1/15/15 4:26 PM for QA/QC to EML 2.1.0
Version 05: August 14, 2019, data and metadata updates to comply with importation to DEIMS7 and LTER Data Portal. Used MarcrosExportEML_HTML (working)pie_excel2007_Jun2019.xlsm 6/7/19 12:58 PM for QA/QC to EML 2.1.0