Emplacement and Denudation History of the Lewis-Eldorado-Hoadley Thrust Slab in the Northern Montana Cordillera, USA: Implications for Steady-State Orogenic Processes
Clicks: 1
ID: 298744
2001
Article Quality & Performance Metrics
Overall Quality
Not rated
Combines reader engagement with the AI quality analysis. This
article has not been analysed, so there is no overall score —
reader engagement is measured and shown alongside.
Reader Engagement
0.0
/100
1 views
0 readers
AI Quality Assessment
Not analyzed
Readership in this journal
Ranked #5,442 of 8,486 articles by views in american journal of science
Most read
Least read
Bar heights use a square-root scale. Only the 120 most-read articles are drawn; the journal has 8,486 in total.
Mint this article as an NFT
Not yet mintedCreate a permanent, verifiable on-chain record of this article on the Scimatic Network. The NFT is held in your Journament account, and you can withdraw it to your own wallet at any time.
5
SUSD
one-off · no wallet required
Abstract
The northern Montana Cordilleran mountain chain provides unusual opportunities to evaluate long-term orogenic processes in a foreland thrust belt. The thick Lewis-Eldorado-Hoadley thrust slab and an imbricated thrust wedge in its footwall dominate the structure of the region. The slab is composed of the displaced Mesoproterozoic Belt-Purcell depositional basin and overlying Phanerozoic strata, tectonically inverted into the broad, deeply dissected Purcell anticlinorium. The geometric simplicity and stratigraphic integrity of the structurally strong, thick slab constrain crustal-scale cross sections. Horizontal displacement of the slab increases from 40 km in central western Montana to 140 km at the United States-Canada border. Thermochronometers from the exhumed thrust slab and its footwall coupled with erosional products in the neighboring foreland basin measure regional denudation during Maastrichtian to middle Paleocene tectonic convergence. During the 15 my period of slab emplacement (74-59 Ma), regional denudation appears to have been minimal as the footwall subsided isostatically beneath the advancing tectonic load; erosion did not breach the Paleozoic cover of the slab. Similarities in burial and denudation patterns from central Montana to southern Canada indicate that regional erosional denudation was steady-state with respect to horizontal displacement and displacement rate. The steady-state configuration of the slab was interrupted immedi- ately upon cessation of thrusting at 59 Ma, when major uplift and denudation of the slab and its footwall began, yoked to isostatic rebound of an autochthonous mega- thrust ramp at the depositional margin of the Belt-Purcell basin. The post-thrusting rebound bent the slab into the Purcell anticlinorium, and the flexure was accompanied by extensional faulting of the slab. Although parameters of orogenic relief are limited by its ancient nature, the northern Montana Cordillera is significant to evaluation of steady-state orogenic processes because its history is clearly divided into a syn-orogenic phase with low denudation rates and an immediate post-orogenic rebound phase with high denudation rates.
| Reference Key |
openalex_W2134191993
Use this key to autocite in the manuscript while using
SciMatic Manuscript Manager or Thesis Manager
|
|---|---|
| Authors | James W. Sears |
| Journal | american journal of science |
| Year | 2001 |
| DOI |
10.2475/ajs.301.4-5.359
|
| URL | |
| Keywords | Keywords not found |
Citations
No citations found. To add a citation, contact the admin at info@scimatic.org
Comments
No comments yet. Be the first to comment on this article.