Mineralogic composition of cryogenic evaporites determined by low-temperature X-ray diffactometry

Summary

Abstract:

As part of a collaborative investigation between researchers at Rice University, Arkansas State University, University of Rochester, and Ohio State University, lakes of the McMurdo Dry Valleys were sampled at discreet depth intervals during the 2005-2006 field season. Sample splits were subsequently analyzed for chemical and isotopic composition of both gases and dissolved ions, as well as dissolved organic carbon. In addition, cryogenic salts were sampled in the surrounding lake shores in order to determine the salt sources. Gravity cores were also obtained and in the case of Lake Vanda, a white precipitate was recovered from the lake bottom.

Presented in this file is the mineralogic composition of salt crusts that were collected on the surface of sediment and rocks surrounding the lakes, as well as the lake-bottom precipitate from Lake Vanda. The results are based on low-temperature XRD determinations, and Rietveld refinement of whole peaks.

Date Range:

December 21, 2005 to December 27, 2005

Data Citation

Snyder, G. 2014. Mineralogic composition of cryogenic evaporites determined by low-temperature X-ray diffactometry. Environmental Data Initiative. DOI: 10.6073/pasta/72e6d378488670471e477a79d73c10d2. Dataset accessed 14 October 2024.

Dataset(s)

Variables (click to expand):

DATASET_CODE

Label:
Definition: Table Identifier
Type: Nominal
Missing values: None specified

LOCATION_NAME

Label: Location Name
Definition: Name of lake where measurement was made
Type: Nominal
Missing values: None specified

Location_Type

Label:
Definition: Sample type description and/or location
Type: Nominal
Missing values: None specified

Sample_ID

Label:
Definition: Sample identification code
Type: Nominal
Missing values: None specified

Latitude

Label:
Definition: Sample Latitude
Type: Physical quantity
Unit: degree
Maximum: Not specified
Minimum: Not specified
Precision: Not specified
Missing values:
- Null = None given

Longitude

Label:
Definition: Sample Longitude
Type: Physical quantity
Unit: degree
Maximum: Not specified
Minimum: Not specified
Precision: Not specified
Missing values:
- Null = None given

Date_time

Label:
Definition: Date sample was collected
Type: Date/time
Date format: mm/dd/yyyy
Missing values: None specified

Halite

Label:
Definition: Percent composition of halite
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

Antarcticite

Label:
Definition: Percent composition of Antarcticite
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

Thenardite

Label:
Definition: Percent composition of Thenardite
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

Mirabilite

Label:
Definition: Percent composition of Mirabilite
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

Gypsum

Label:
Definition: Percent composition of Gypsum
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

Calcite

Label:
Definition: Percent composition of Calcite
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

Aragonite

Label:
Definition: Percent composition of Aragonite
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

Quartz

Label:
Definition: Percent composition of Quartz
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

Albite

Label:
Definition: Percent composition of Albite
Type: Physical quantity
Unit: dimensionless
Maximum: 100
Minimum: 0
Precision: Not specified
Missing values:
- NULL = None given

File:

ANCILLARY_SNYDER_SALTS.csv (4.11 KB)

Short name:

snyder_salts

Dataset ID:

6003

People

Principal Investigator(s):

Glen Snyder

Contact:

McMurdo Dry Valleys LTER

Associated Personnel:

Data Manager

Methodology

Methods:

Salts were collected in the areas surrounding the Dry Valley lakes. The samples were bagged and then placed either in boxes or in plastic containers in order to avoid crushing them. The samples were stored in a freezer at -40 C, prior to shipping, due to the instability of Antarcticite at room temperatures. The samples were then shipped under dry ice to Rice University in Houston, then shipped to the Steacie Institute for Molecular Sciences in Ottawa, which is a division of the Canadian Research Council.

Hailong Lu, a research scientist in the Institute whose specialty is on the structure of marine gas hydrates, placed each sample in a mortar with liquid nitrogen and then ground it into a powder. The powders were then analyzed with a low-temperature XRD. Temperatures were first dropped to -140 C, then gradually ramped up to room temperature to look at phase changes that occurred on warming. Minerals were identified JADE 8.5 data processing software, and the ICDD PDF-2 Data Base. The relative abundance of each crygenic mineral was dertermined by the Rietveld method of whole-peak fitting.

Maintenance:

Metadata completed in 2016

This dataset was created Oct 1, 2008 by MCM-LTER information manager (Chris Gardner) after email discussion with PI Glen Snyder.

Additional information:

This material is based upon work supported by the National Science Foundation under Grant No.0440686

Research Section:

LTER Core Areas:

inorganic nutrients

MCM Keywords:

Keywords:

Metadata Download