Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1130/B31595.1 |
Timing and deformation conditions of the Tallulah Falls dome, NE Georgia: Implications for the Alleghanian orogeny | |
Casale, Gabriele1; Levine, Jamie S. F.1; Craig, Taylor D.1,2; Stewart, Craig1,3 | |
2017-09-01 | |
发表期刊 | GEOLOGICAL SOCIETY OF AMERICA BULLETIN |
ISSN | 0016-7606 |
EISSN | 1943-2674 |
出版年 | 2017 |
卷号 | 129 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | Structural domes composed of crystalline rocks metamorphosed to midcrustal conditions are present in every major orogen and record deformation of the deep interior of mountain ranges. The Tallulah Falls dome in northeast Georgia is a shear zone-bounded body of metasedimentary rocks that is defined by a foliation pattern that crosscuts the regional fabric of the Eastern Blue Ridge crystalline nappe in the southern Appalachian Mountains. Previously, the Tallulah Falls dome was interpreted as the expression of duplexed underlying slices of Laurentian margin sedimentary rocks imbricated during Alleghanian emplacement of the allochthonous Blue Ridge thrust sheet under greenschist-facies conditions. We provide new observations of quartz and feldspar recrystallization fabrics and new Ar-40/Ar-39 dates from muscovite that complement existing thermochronometric ages to determine the timing and conditions of doming within the Tallulah Falls dome. Our microstructural observations are consistent with deformation mechanisms active dominantly at amphibolite-facies conditions, with some samples recording temperatures in excess of 650 degrees C. Thermochronometric ages define a period of relatively rapid cooling from similar to 550 degrees C to 340 degrees C within and around the Tallulah Falls dome between 321 and 317 Ma, with differential cooling across the northwestern dome-bounding shear zone lasting until at least 313 Ma. Our observations reveal a period of early Alleghanian cooling from amphibolite- to greenschist-facies conditions associated with displacement along a shear zone bounding the Tallulah Falls dome. Across the Blue Ridge, the Alleghanian orogeny has long been characterized only by thrusting at greenschist-facies conditions. Similarly, dome formation has been interpreted as the result of duplexing within the thin-skinned Blue Ridge crystalline thrust sheet as it was emplaced upon the Laurentian margin. Both of these interpretations are inconsistent with the new data presented here, which suggest more complex Alleghanian deformation over a broader range in temperatures, and perhaps a diverse suite of structural styles. Our results are best explained by doming of the footwall of a normal-displacement shear zone at amphibolite-facies conditions during the earliest Alleghanian period. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000409330000010 |
WOS关键词 | METAMORPHIC CORE COMPLEX ; EASTERN BLUE RIDGE ; SOUTHERN APPALACHIAN OROGEN ; SOUTHWESTERN NORTH-CAROLINA ; AR-40-AR-39 AGE-SPECTRA ; TECTONOTHERMAL EVOLUTION ; FISSION-TRACK ; AR-40/AR-39 THERMOCHRONOLOGY ; WESTERN PIEDMONT ; GRANITIC-ROCKS |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/24813 |
专题 | 地球科学 |
作者单位 | 1.Appalachian State Univ, Dept Geol, ASU Box 32067, Boone, NC 28607 USA; 2.Univ Nevada, Dept Geosci, 4505 S Maryland Pkwy, Las Vegas, NV 89154 USA; 3.Calif State Univ Northridge, Dept Geol Sci, Live Oak 1202,18111 Nordhoff St, Northridge, CA 91330 USA |
推荐引用方式 GB/T 7714 | Casale, Gabriele,Levine, Jamie S. F.,Craig, Taylor D.,et al. Timing and deformation conditions of the Tallulah Falls dome, NE Georgia: Implications for the Alleghanian orogeny[J]. GEOLOGICAL SOCIETY OF AMERICA BULLETIN,2017,129. |
APA | Casale, Gabriele,Levine, Jamie S. F.,Craig, Taylor D.,&Stewart, Craig.(2017).Timing and deformation conditions of the Tallulah Falls dome, NE Georgia: Implications for the Alleghanian orogeny.GEOLOGICAL SOCIETY OF AMERICA BULLETIN,129. |
MLA | Casale, Gabriele,et al."Timing and deformation conditions of the Tallulah Falls dome, NE Georgia: Implications for the Alleghanian orogeny".GEOLOGICAL SOCIETY OF AMERICA BULLETIN 129(2017). |
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