Stable Isotope and Environmental Laboratory

stable isotope ratio mass spectrometerThe Stable Isotope and Environmental Laboratory (SIEL) is located in the Department of Geology and Geological Engineering at Colorado School of Mines and provides analytical training and services relevant to geosciences and (paleo)environmental studies to students, faculty, and other researchers at Mines, other universities, federal agencies and industry.

The centerpiece of the facility is an IsoPrime Isotope Ratio Mass Spectrometer (IRMS) currently measuring the stable isotope ratios of carbon and nitrogen of solid organic samples. The laboratory also offers analytical methods for the characterization of organic, carbonate, and volatile-rich soil and rock samples (loss-on-ignition analysis).

SIEL also conducts pollen-based research which represents an important tool in stratigraphy, paleoenvironmental studies, archaeology, and forensic investigations.


Department of Geology and Geological Engineering
Berthoud Hall 404
Colorado School of Mines
1516 Illinois Street
Golden, CO 80401

Dr. Susann Stolze
Fax: 303-273-3859


The SIEL is equipped with the following instruments:

  • IsoPrime Isotope Ratio Mass Spectrometer (IRMS)
  • EuroVector Elemental Analyzer



C & N Isotopic Analyses

Service Fees for C & N Analyses:

ServiceInternal RateExternal Rate
Acid fumigation (per sample)$4.00$6.20
Freeze drying (per sample)$5.00$7.75
Sample drying (per sample)$2.50$3.85
Weighing and encapsulation (per sample)$2.50$3.85
δ13C analysis of organics via EA-IRMS with weight percent elemental composition (per sample)$8.00$12.40
δ15N analysis via EA-IRMS with weight percent elemental composition (per sample)$8.00$12.40


Loss-on-ignition analysis

Loss-on-ignition is a test widely used in geochemistry to determine the volatile content of rocks, soils, lake sediments, and other materials. Samples are heated at a specified temperature allowing volatile substances to escape. The heating is done in air to oxidize the samples.

The SIEL offers two different types of loss-on-ignition analyses for organic-rich samples such as soils and lake sediments. The organic carbon content of the samples is determined through loss-on-ignition analysis at 550°C. The inorganic carbon content is measured through ignition at 950°C. The analyses are performed following the protocol of Heiri et al. (2001).

The volatile loss of powdered whole-rock samples is determined at 1050°C. This method is most widely used in the geochemical analysis of rocks and supplements whole-rock major element data determined by X-ray fluorescence or other techniques. 

Service Fees for Loss-on-Ignition Analyses:

ServiceInternal RateExternal Rate
Sample drying (per sample)$2.50$3.85
Loss-on-ignition analysis of organic carbon at 550°C (per sample) $10.00$15.50
Loss-on-ignition analysis of organic carbon at 550°C and inorganic carbon at 950°C (per sample)$15.00$23.25
Loss-on-ignition analysis for whole-rock geochemistry at 1050°C (per sample)$10.00$15.50

Palynological Analyses

Palynological Services:

Please request a quote from the laboratory manager.

Sample Preparation Equipment

The SIEL is equipped with a fully operational sample preparation facility. This includes dry and wet lab facilities.


The furnace has a heating area of 2 L and can be operated over a temperature range of 100 to 1200°C.


The oven is used to dry samples prior to loss-on-ignition or isotopic analysis.


Ultrasonic precision cleaning bath for small- and medium-sized objects that can also be used for sample preparation and degassing of liquids. The bath is equipped with a stainless steel basket.


The ultra-compact mill is ideal for fine comminution of smallest quantities of medium-hard, brittle and moist samples (wet, dry, or cryogenic). Its special spherical grinding bowl ensures a high performance in grinding, mixing, and homogenizing.


This high performance centrifuge has a maximum capacity of 4×750 ml, with a maximum of 15,000 rotations per minute and a maximum relative centrifugal force of 24,400 g.