Sr isotope stratigraphy across the Paasivaara PGE reef of the Penikat intrusion, Northern Finland:insights into the genesis of reef-type PGE mineralization
Abstract. Layered mafic-ultramafic intrusions host the largest reserves of feasible PGE commodities. Worldwide rare in the geological record, these deposits are well-constrained in a few large igneous provinces. Despite extensive research on layered intrusions and related PGE ores, the models regard...
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ftunivoulu:oai:oulu.fi:nbnfioulu-202205162080 2023-07-30T04:05:50+02:00 Sr isotope stratigraphy across the Paasivaara PGE reef of the Penikat intrusion, Northern Finland:insights into the genesis of reef-type PGE mineralization Rivas de la Torre, I. (Isaac) 2022-05-16 application/pdf http://jultika.oulu.fi/Record/nbnfioulu-202205162080 eng eng University of Oulu info:eu-repo/semantics/openAccess © Isaac Rivas de la Torre, 2022. Except otherwise noted, the reuse of this document is authorised under a Creative Commons Attribution 4.0 International (CC-BY 4.0) licence (https://creativecommons.org/licenses/by/4.0/). This means that reuse is allowed provided appropriate credit is given and any changes are indicated. For any use or reproduction of elements that are not owned by the author(s), permission may need to be directly from the respective right holders. Geotieteet info:eu-repo/semantics/masterThesis info:eu-repo/semantics/publishedVersion 2022 ftunivoulu 2023-07-08T19:59:24Z Abstract. Layered mafic-ultramafic intrusions host the largest reserves of feasible PGE commodities. Worldwide rare in the geological record, these deposits are well-constrained in a few large igneous provinces. Despite extensive research on layered intrusions and related PGE ores, the models regarding the PGE ore-formation are diverse, involving both magmatic and hydrothermal processes, and the subject remains largely debatable. In Europe, research efforts around the Baltic Large Igneous Province (BLIP) has doubled due to the new geopolitical strategy of the European Union in their search for new sources of critical metals. Global politics have placed Finnish mafic-ultramafic layered intrusions in the spotlight. Penikat is a Paleoproterozoic 2.44 Ga layered intrusion part of the east-west trending Tornio-Näränkävaara belt in northern Finland. The exposed intrusion is 23 km long and 1.5 km to 3.5 km on the current erosional level. Based on seismic and gravimetric data, it extends to 2.5 km deep. The intrussion is split into five westward-dipping blocks: Sompujärvi, Kilkka, Yli-Penikka, Keski-Penikka, and Ala-Penikka. Traditionally, Penikat is divided into five megacyclic units (MCU I-MCU V), hosting three main PGE reef horizons: the Sompujärvi Reef (SJ), located to the basal part of MCU IV; the Ala-Penikka Reef (AP), occurring within the lower proportion of unit IV; and the Paasivaara Reef (PV), which defines the hanging wall contact from the MCU IV to the MCU V. The present study comprises 700 m of stratigraphy in the Ala-Penikka block and focuses on the Paasivaara reef (PV). This platinum-enriched reef appears at the Transition Zone (TZ), along the MCU IV-V boundary. To gain new insight into Penikat’s petrogenesis, we utilize fourteen thick section samples from historic drill cores, both intersecting the PV reef, and two additional samples made after hand specimens. The sections were reviewed using petrologic microscopy before subjecting them to geochemical analyses. From these sections, we obtained new ... Master Thesis Northern Finland Jultika - University of Oulu repository Ala-Penikka ENVELOPE(25.000,25.000,65.817,65.817) Sompujärvi ENVELOPE(25.167,25.167,65.950,65.950) Tornio ENVELOPE(24.147,24.147,65.848,65.848) |
institution |
Open Polar |
collection |
Jultika - University of Oulu repository |
op_collection_id |
ftunivoulu |
language |
English |
topic |
Geotieteet |
spellingShingle |
Geotieteet Rivas de la Torre, I. (Isaac) Sr isotope stratigraphy across the Paasivaara PGE reef of the Penikat intrusion, Northern Finland:insights into the genesis of reef-type PGE mineralization |
topic_facet |
Geotieteet |
description |
Abstract. Layered mafic-ultramafic intrusions host the largest reserves of feasible PGE commodities. Worldwide rare in the geological record, these deposits are well-constrained in a few large igneous provinces. Despite extensive research on layered intrusions and related PGE ores, the models regarding the PGE ore-formation are diverse, involving both magmatic and hydrothermal processes, and the subject remains largely debatable. In Europe, research efforts around the Baltic Large Igneous Province (BLIP) has doubled due to the new geopolitical strategy of the European Union in their search for new sources of critical metals. Global politics have placed Finnish mafic-ultramafic layered intrusions in the spotlight. Penikat is a Paleoproterozoic 2.44 Ga layered intrusion part of the east-west trending Tornio-Näränkävaara belt in northern Finland. The exposed intrusion is 23 km long and 1.5 km to 3.5 km on the current erosional level. Based on seismic and gravimetric data, it extends to 2.5 km deep. The intrussion is split into five westward-dipping blocks: Sompujärvi, Kilkka, Yli-Penikka, Keski-Penikka, and Ala-Penikka. Traditionally, Penikat is divided into five megacyclic units (MCU I-MCU V), hosting three main PGE reef horizons: the Sompujärvi Reef (SJ), located to the basal part of MCU IV; the Ala-Penikka Reef (AP), occurring within the lower proportion of unit IV; and the Paasivaara Reef (PV), which defines the hanging wall contact from the MCU IV to the MCU V. The present study comprises 700 m of stratigraphy in the Ala-Penikka block and focuses on the Paasivaara reef (PV). This platinum-enriched reef appears at the Transition Zone (TZ), along the MCU IV-V boundary. To gain new insight into Penikat’s petrogenesis, we utilize fourteen thick section samples from historic drill cores, both intersecting the PV reef, and two additional samples made after hand specimens. The sections were reviewed using petrologic microscopy before subjecting them to geochemical analyses. From these sections, we obtained new ... |
format |
Master Thesis |
author |
Rivas de la Torre, I. (Isaac) |
author_facet |
Rivas de la Torre, I. (Isaac) |
author_sort |
Rivas de la Torre, I. (Isaac) |
title |
Sr isotope stratigraphy across the Paasivaara PGE reef of the Penikat intrusion, Northern Finland:insights into the genesis of reef-type PGE mineralization |
title_short |
Sr isotope stratigraphy across the Paasivaara PGE reef of the Penikat intrusion, Northern Finland:insights into the genesis of reef-type PGE mineralization |
title_full |
Sr isotope stratigraphy across the Paasivaara PGE reef of the Penikat intrusion, Northern Finland:insights into the genesis of reef-type PGE mineralization |
title_fullStr |
Sr isotope stratigraphy across the Paasivaara PGE reef of the Penikat intrusion, Northern Finland:insights into the genesis of reef-type PGE mineralization |
title_full_unstemmed |
Sr isotope stratigraphy across the Paasivaara PGE reef of the Penikat intrusion, Northern Finland:insights into the genesis of reef-type PGE mineralization |
title_sort |
sr isotope stratigraphy across the paasivaara pge reef of the penikat intrusion, northern finland:insights into the genesis of reef-type pge mineralization |
publisher |
University of Oulu |
publishDate |
2022 |
url |
http://jultika.oulu.fi/Record/nbnfioulu-202205162080 |
long_lat |
ENVELOPE(25.000,25.000,65.817,65.817) ENVELOPE(25.167,25.167,65.950,65.950) ENVELOPE(24.147,24.147,65.848,65.848) |
geographic |
Ala-Penikka Sompujärvi Tornio |
geographic_facet |
Ala-Penikka Sompujärvi Tornio |
genre |
Northern Finland |
genre_facet |
Northern Finland |
op_rights |
info:eu-repo/semantics/openAccess © Isaac Rivas de la Torre, 2022. Except otherwise noted, the reuse of this document is authorised under a Creative Commons Attribution 4.0 International (CC-BY 4.0) licence (https://creativecommons.org/licenses/by/4.0/). This means that reuse is allowed provided appropriate credit is given and any changes are indicated. For any use or reproduction of elements that are not owned by the author(s), permission may need to be directly from the respective right holders. |
_version_ |
1772818100382597120 |