Characterizing some major Archean faults at depth in the Superior craton, North America

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F25%3A00638963" target="_blank" >RIV/67985530:_____/25:00638963 - isvavai.cz</a>

Výsledek na webu

<a href="https://se.copernicus.org/articles/16/785/2025/" target="_blank" >https://se.copernicus.org/articles/16/785/2025/</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/se-16-785-2025" target="_blank" >10.5194/se-16-785-2025</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Characterizing some major Archean faults at depth in the Superior craton, North America

Popis výsledku v původním jazyce

The geometry of ancient (2.75-2.65 Ga) faults at depth can only be mapped in detail by high-resolution geophysical surveys such as seismic reflection profiling. Recent deep (35-48 km) reflection profiles acquired throughout the Archean southern Superior craton of North America provided such data with which to map some major shear zones in 3D, many of which are associated with significant orogenic gold or volcanogenic massive sulfide (VMS) deposits. Most faults are (re-)interpreted as low-angle (<35 degrees) thrusts, a few appear as sub-vertically (>75 degrees) aligned truncations of prominent reflectors. Asymmetry of reflectors suggests that the sub-vertical faults may have originated as 2.75-2.70 Ga syn-volcanic leaky transform faults. We relate thrust structures primarily to the dominant phase of folding and horizontal shortening strain that occurred at 2.72-2.66 Ga during regional crustal deformation, mineralization, and peak metamorphism, associated with terrane accretion. Palinspastic restoration near Timmins, Ontario, indicates 40 km of horizontal shortening. Previous mapping indicates that deformation after this orogenic shortening event resulted in modest lateral movement. Coincident magnetotelluric (MT) surveys indicate that pervasive conductive minerals, such as graphite/carbon and sulfide, exist within the mid-crust and in near-vertical channels within the more brittle and resistive upper crust. Many such channels, but not all, coincide with fault zones and mineral deposits. Palinspastic and paleomagnetic-based reconstructions suggest many faults had multiple periods of activity with evolving vertical to horizontal offsets. Some prominent faults appear paired, partitioning normal and oblique strains on vertical shear zones and dipping thrust zones, respectively.

Název v anglickém jazyce

Characterizing some major Archean faults at depth in the Superior craton, North America

Popis výsledku anglicky

The geometry of ancient (2.75-2.65 Ga) faults at depth can only be mapped in detail by high-resolution geophysical surveys such as seismic reflection profiling. Recent deep (35-48 km) reflection profiles acquired throughout the Archean southern Superior craton of North America provided such data with which to map some major shear zones in 3D, many of which are associated with significant orogenic gold or volcanogenic massive sulfide (VMS) deposits. Most faults are (re-)interpreted as low-angle (<35 degrees) thrusts, a few appear as sub-vertically (>75 degrees) aligned truncations of prominent reflectors. Asymmetry of reflectors suggests that the sub-vertical faults may have originated as 2.75-2.70 Ga syn-volcanic leaky transform faults. We relate thrust structures primarily to the dominant phase of folding and horizontal shortening strain that occurred at 2.72-2.66 Ga during regional crustal deformation, mineralization, and peak metamorphism, associated with terrane accretion. Palinspastic restoration near Timmins, Ontario, indicates 40 km of horizontal shortening. Previous mapping indicates that deformation after this orogenic shortening event resulted in modest lateral movement. Coincident magnetotelluric (MT) surveys indicate that pervasive conductive minerals, such as graphite/carbon and sulfide, exist within the mid-crust and in near-vertical channels within the more brittle and resistive upper crust. Many such channels, but not all, coincide with fault zones and mineral deposits. Palinspastic and paleomagnetic-based reconstructions suggest many faults had multiple periods of activity with evolving vertical to horizontal offsets. Some prominent faults appear paired, partitioning normal and oblique strains on vertical shear zones and dipping thrust zones, respectively.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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OECD FORD obor

10505 - Geology

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Solid Earth

ISSN

1869-9510

e-ISSN

1869-9529

Svazek periodika

16

Číslo periodika v rámci svazku

9

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

22

Strana od-do

785-806

Kód UT WoS článku

001566050200001

EID výsledku v databázi Scopus

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