A diverse suite of tholeiitic to alkaline basalt and gabbroic intrusions located in the Coldwell Complex on the northern margin of the Midcontinent Rift exhibit unusual trace element signatures that show enriched large ion lithophile elements and light rare earth elements with negative Nb and Zr anomalies. These features are not typical of magmas derived by partial melting within or above a rising mantle plume, as might be expected in an early Midcontinent Rift magmatic event. In this paper, we provide a detailed geochemical study of a 500 m thick sequence of metabasalt that represents the earliest stage of magmatism in the Coldwell Complex. We show that contamination or crystallization processes or subsequent metasomatism cannot explain the trace element variations. Instead, we propose partial melting in a metasomatized Subcontinental Lithospheric Mantle source to explain the decoupled behavior of large ion lithophile elements from light rare earth elements and heavy rare earth elements and rare earth elements from high field strength elements and the enriched Nd isotope signature of metabasalt. Similar features occur in unit 5b of the Mamainse Point Volcanic Group located at the northern margin of the Rift. An objective of this paper is to relate Two Duck Lake gabbro, host rock for low-sulfur, high precious metal sulfide mineralization at the Marathon deposit, to the metabasalt sequence. The excellent match of trace element abundances in Two Duck Lake gabbro to metabasalt unit 3 confirms an early Coldwell Complex age for metabasalt and a Subcontinental Lithospheric Mantle source for Cu – platinum group element mineralized gabbros.
Skip Nav Destination
Article navigation
Research Article|
February 07, 2019
Significance of the metasomatized lithospheric mantle in the formation of early basalts and Cu – platinum group element sulfide mineralization in the Coldwell Complex, Midcontinent Rift, Canada1
David J. Good;
Department of Earth Sciences, Western University, ON N6A 5B7, Canada.
Corresponding author: David J. Good (email: [email protected]).
Search for other works by this author on:
Peter C. Lightfoot
Peter C. Lightfoot
Department of Earth Sciences, Western University, ON N6A 5B7, Canada.
Search for other works by this author on:
Peter C. Lightfoot
Department of Earth Sciences, Western University, ON N6A 5B7, Canada.
Corresponding author: David J. Good (email: [email protected]).
Publisher: Canadian Science Publishing
Received:
05 Feb 2018
Accepted:
30 Jan 2019
First Online:
23 Jul 2019
Online ISSN: 1480-3313
Print ISSN: 0008-4077
Published by NRC Research Press
Canadian Journal of Earth Sciences (2019) 56 (7): 693–714.
Article history
Received:
05 Feb 2018
Accepted:
30 Jan 2019
First Online:
23 Jul 2019
Citation
David J. Good, Peter C. Lightfoot; Significance of the metasomatized lithospheric mantle in the formation of early basalts and Cu – platinum group element sulfide mineralization in the Coldwell Complex, Midcontinent Rift, Canada. Canadian Journal of Earth Sciences 2019;; 56 (7): 693–714. doi: https://doi.org/10.1139/cjes-2018-0042
Download citation file:
You could not be signed in. Please check your email address / username and password and try again.
Email alerts
Index Terms/Descriptors
- alkali metals
- alkaline earth metals
- Canada
- chemical composition
- Coldwell Complex
- copper ores
- Eastern Canada
- fractional crystallization
- isotope ratios
- isotopes
- Keweenawan Rift
- lithosphere
- magmas
- mantle
- metabasalt
- metaigneous rocks
- metal ores
- metals
- metamorphic rocks
- metasomatism
- mineralization
- Nd-144/Nd-143
- neodymium
- North America
- Ontario
- petrography
- platinum group
- Precambrian
- Proterozoic
- radioactive isotopes
- rare earths
- Rb-87/Sr-86
- rubidium
- Sr-87/Sr-86
- stable isotopes
- strontium
- trace elements
- upper Precambrian
- Marathon Deposit
Latitude & Longitude
Citing articles via
Related Articles
Mafic and ultrapotassic rocks from the Canyon domain (central Grenville Province): geochemistry and tectonic implications
Canadian Journal of Earth Sciences
Isotope constraints on the origin of Pan-African granitoid rocks in the Kaoko belt, NW Namibia
South African Journal of Geology
Related Book Content
Geochemical and Nd-Sr-Pb isotopic evolution of metabasites from rifting of continental lithosphere, Seward Peninsula, Alaska, and implications for paleogeographic reconstruction
Reconstruction of a Late Proterozoic to Devonian Continental Margin Sequence, Northern Alaska, Its Paleogeographic Significance, and Contained Base-Metal Sulfide Deposits
The mantle isotopic printer: Basic mantle plume geochemistry for seismologists and geodynamicists
The Interdisciplinary Earth: A Volume in Honor of Don L. Anderson
Contrasting mantle sources and processes involved in a peri-Gondwanan terrane: A case study of pre-Variscan mafic intrusives from the autochthon of the Central Iberian Zone
The Evolution of the Rheic Ocean: From Avalonian-Cadomian Active Margin to Alleghenian-Variscan Collision
Late Mesozoic to Quaternary intraplate magmatism and its relation to the Neoproterozoic lithosphere in NE Africa—New data from lower-crustal and mantle xenoliths from the Bayuda volcanic field, Sudan
Volcanism and Evolution of the African Lithosphere