Structural Geology Algorithms

Allmendinger, Richard W.; Cardozo, Néstor; Fisher, Donald M.

doi:10.1017/cbo9780511920202

Cited by 254 publications

(128 citation statements)

References 0 publications

Supporting

Mentioning

120

Contrasting

Unclassified

Order By: Relevance

“…(b) Lower hemisphere stereonet plot of mylonitic foliations and lineations measured along the Wildhorse Mountain thrust. Stereonet and eigenvalues were produced with Stereonet 10.0 software (Allmendinger et al, 2012;Cardozo & Allmendinger, 2013). (c) S-C mylonites at the extreme southwest end of the Wildhorse Mountain thrust indicating top-northeast shearing.…”

Section: Total Extension and Hypothetical Reconstructionmentioning

confidence: 99%

Reconstruction of Mid‐Cenozoic Extension in the Rincon Mountains Area, Southeastern Arizona, USA, and Geodynamic Implications

et al. 2019

View full text Add to dashboard Cite

The Rincon Mountains metamorphic core complex, located east of Tucson, Arizona, consists of an arched footwall of foliated crystalline rocks bounded above by the generally outward dipping, Oligocene‐Miocene San Pedro extensional detachment fault. The southwest trending axes of corrugations in the detachment fault, and in footwall foliation and lithologic layering, parallel mylonitic lineation, and inferred top‐southwest displacement on the fault. An upper plate fault block within a synformal fault groove on the west side of the Rincon Mountains contains a thrust fault that is interpreted as displaced 34‐38 km westward from an original position adjacent to a similar thrust in the footwall of the San Pedro detachment fault. Much of the footwall of the detachment fault in the eastern Rincon Mountains consists of metasedimentary tectonites derived largely from Paleozoic carbonates that were buried beneath Proterozoic crystalline rocks forming the hanging wall of the Laramide Wildhorse Mountain thrust. These tectonites were later exhumed by displacement on the San Pedro detachment fault. Structural reconstruction supports the interpretation that the carbonate tectonites localized extensional faulting along the San Pedro detachment fault at crustal depths where carbonates would be weak and deform by crystal plasticity while quartzo‐feldspathic rocks would be strong and brittle. This weak zone is located adjacent to the greatest width of exposed extension‐parallel mylonitic fabrics in southeastern Arizona and may have been associated with the earliest initiation of extension in the region. Domains of low‐strength carbonates may be an underappreciated influence on extensional tectonics in cratonic southwestern North America.

show abstract

Section: Total Extension and Hypothetical Reconstructionmentioning

confidence: 99%

Reconstruction of Mid‐Cenozoic Extension in the Rincon Mountains Area, Southeastern Arizona, USA, and Geodynamic Implications

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Orientation data (e.g., foliation of basement rocks, fault slip, and plane) are displayed as stereoplots using OSXStereonet [Allmendinger et al, 2011;Cardozo and Allmendinger, 2013] (Table 1). Furthermore, fault gouges and basement rocks have been sampled for radiocarbon dating (Tables 1 and 3) and apatite fission tracks analysis (see section 5), respectively.…”

Section: Structure and 14 C Dating Of The Different Rift Sectorsmentioning

confidence: 99%

Evolution, distribution, and characteristics of rifting in southern Ethiopia

et al. 2014

View full text Add to dashboard Cite

Southern Ethiopia is a key region to understand the evolution of the East African rift system, since it is the area of interaction between the main Ethiopian rift (MER) and the Kenyan rift. However, geological data constraining rift evolution in this remote area are still relatively sparse. In this study the timing, distribution, and style of rifting in southern Ethiopia are constrained by new structural, geochronological, and geomorphological data. The border faults in the area are roughly parallel to preexisting basement fabrics and are progressively more oblique with respect to the regional Nubia-Somalia motion proceeding southward. Kinematic indicators along these faults are mainly dip slip, pointing to a progressive rotation of the computed direction of extension toward the south. Radiocarbon data indicate post 30 ka faulting at both western and eastern margins of the MER with limited axial deformation. Similarly, geomorphological data suggest recent fault activity along the western margins of the basins composing the Gofa Province and in the Chew Bahir basin. This supports that interaction between the MER and the Kenyan rift in southern Ethiopia occurs in a 200 km wide zone of ongoing deformation. Fault-related exhumation at~10-12 Ma in the Gofa Province, as constrained by new apatite fission track data, occurred later than the~20 Ma basement exhumation of the Chew Bahir basin, thus pointing to a northward propagation of the Kenyan rift-related extension in the area.

show abstract

“…Structural measurements (Table S1) were processed in the Stereonet software (version 10.2.8, Cornell University, Ithaca, NY, USA) by Richard W. Allmendinger, using algorithms of Allmendinger et al [44] and Cardozo and Allmendinger [45]. Samples of serpentinite, talc schist, barren metagabbro and metadiabase, Fe-Ti-V-mineralized hornblendite, dolomite vein, chlorite schist and country rocks (i.e., marble, mica schist, paragneiss, and syenite vein hosted in the paragneiss) were examined.…”

Section: Methodsmentioning

confidence: 99%

Origin of Talc and Fe-Ti-V Mineralization in the Kletno Deposit (the Śnieżnik Massif, SW Poland)

et al. 2019

View full text Add to dashboard Cite

The Kletno deposit in theŚnieżnik Massif (Central Sudetes, SW Poland), mined for Fe, U, Ag, Cu, fluorite, and marble through the ages, developed at the contact of marbles and orthogneiss. Here, we present a new Fe-Ti-V-ore (containing up to 14.07 wt. % Fe, 2.05 wt. % Ti, and 2055 ppm V in bulk rock) and ornamental-to gem-quality talc prospect at the southwest margin of this deposit. This newly documented Fe-Ti-V mineralization is hosted in hornblendites, dolomite veins, and chlorite schists, which, along with talc, envelopes a tectonic slice of serpentinite. Hornblendites are interpreted as metamorphosed ferrogabbros, derived from the same mafic melts as adjacent barren metagabbros. The oxygen and carbon isotope compositions of metabasites and dolomite veins (amphibole δ 18 O values = 8.8-9.3% ; carbonate δ 18 O values = 12.8-16.0% , and δ 13 C values = −8.3% to −7.2% ), in combination with those of the country marbles (carbonate δ 18 O and δ 13 C values = 23.2% and +0.1% , respectively), suggest that mineralization-bearing hornblendites formed due to interaction of the mafic magma with CO 2 released during the decarbonation of the sediments. The CO 2 -bearing fluid interaction with gabbros likely caused carbonation of the gabbros and formation of the dolomite veins, whereas talc formed due to Si-rich fluids, possibly derived from a mafic intrusion, interaction with serpentinite, or due to the metasomatism of the serpentinite-gabbro assemblage. Moreover, fluids leaching Fe and Ti from the adjacent sediments can mix with the mafic magma causing enrichment of the magma in Fe and Ti. Consequently, the mineralization-bearing ferrogabbros became even more enriched in Fe and Ti, which can be linked with the formation of Fe-Ti-V ore bodies.

show abstract

Structural Geology Algorithms

Cited by 254 publications

References 0 publications

Reconstruction of Mid‐Cenozoic Extension in the Rincon Mountains Area, Southeastern Arizona, USA, and Geodynamic Implications

Reconstruction of Mid‐Cenozoic Extension in the Rincon Mountains Area, Southeastern Arizona, USA, and Geodynamic Implications

Evolution, distribution, and characteristics of rifting in southern Ethiopia

Origin of Talc and Fe-Ti-V Mineralization in the Kletno Deposit (the Śnieżnik Massif, SW Poland)

Contact Info

Product

Resources

About