Authors / CoAuthors
Vinnichenko, G | Jarrett, A.J.M. | Hope, J.M. | Brocks, J.J.
Abstract
Discovery of mid-Proterozoic (1.8 – 0.8 billion years ago, Ga) indigenous biomarkers is a challenge, since biologically informative molecules of such antiquity are commonly destroyed by metamorphism or overprinted by drilling fluids and other anthropogenic petroleum products. The previously oldest biomarkers were reported from the 1.64 Ga Barney Creek Formation in the McArthur Basin, northern Australian. In this study, we present the discovery of clearly indigenous biomarker molecules from carbonaceous shales of the 1.73 Ga Wollogorang Formation in the southern McArthur Basin, extending the biomarker record back in time by ~90 million years. The extracted hydrocarbons illustrate typical mid-Proterozoic signatures with a large unresolved complex mixture, high methyl-alkane/n-alkane ratios and absence of eukaryotic steranes. Also below detection limits were acyclic isoprenoids, saturated carotenoid derivatives, bacterial hopanes and aromatic hopanoids and steroids. Detected, however, were continuous homologous series (C13-C22) of 2,3,4- and 2,3,6-trimethyl aryl isoprenoids (AI). These breakdown products of aromatic carotenoids are the oldest known biogenic molecules, revealing the activity of phototrophic green (Chlorobiaceae) and purple sulphur bacteria (Chromatiaceae). The compounds provide evidence for at least temporary, very shallow (less than ~20 m) stratification of the McArthur Basin 1.73 Ga ago, supporting models of pervasive anoxic conditions in mid-Proterozoic basins.
Product Type
document
eCat Id
130363
Contact for the resource
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Point of contact
Keywords
- theme.ANZRC Fields of Research.rdf
-
- EARTH SCIENCES
-
- aryl isoprenoids
-
- Chlorobiaceae,
-
- Chromatiaceae,
-
- McArthur Basin
-
- Published_External
Publication Date
2020-04-28T04:16:12
Creation Date
2019-06-27T13:00:00
Security Constraints
Legal Constraints
Status
completed
Purpose
Manuscript
Maintenance Information
asNeeded
Topic Category
geoscientificInformation
Series Information
1
Lineage
Not applicable
Parent Information
Extents
[-17.5602, -11.2646, 129.5508, 136.582]
Reference System
Spatial Resolution
Service Information
Associations
Source Information