New multi-dimensional diagrams for tectonic discrimination of siliciclastic sediments and their application to Precambrian basins

Section: Tectonic Settingmentioning

confidence: 99%

Petrography and geochemistry of Pharaonic sandstone monuments in Tall San Al Hagr, Al Sharqiya Governorate, Egypt: implications for provenance and tectonic setting

Zaid¹,

Badry²,

Ramadan³

et al. 2015

“…Two such diagrams to discriminate three tectonic settings have recently been proposed for siliciclastic sediments (Verma and Armstrong-Altrin, 2013), but more work will certainly help to discriminate five tectonic settings (island arc, continental arc, continental rift, ocean island, and collision) from sedimentary rock data. Similarly, the discrimination of conventional settings of active and passive continental margins is also of much interest.…”

Section: Basic Rocksmentioning

confidence: 99%

Origin, evolution, and tectonic setting of the eastern part of the Mexican Volcanic Belt and comparison with the Central American Volcanic Arc from conventional multielement normalized and new multidimensional discrimination diagrams and discordancy and significance tests

Verma¹

2015

Self Cite

If both the Mexican Volcanic Belt (MVB) and the Central American Volcanic Arc (CAVA) have been related to the subduction of the Cocos plate beneath the North American and Caribbean plates, respectively, their magmas, and especially the less evolved basic varieties, should show considerable similarities. The conventional multielement normalized diagrams indicate more complex petrogenetic processes for the MVB than the CAVA. Forty-five statistically coherent tectonomagmatic discrimination diagrams were used to infer the tectonic setting of the controversial geological subprovince of the eastern part of the MVB (E-MVB). Basic rocks from the E-MVB indicated a continental rift setting, whereas the intermediate rocks were more consistent with a transitional setting of rift to collision. The acid rocks, presumably having a larger crustal component than the intermediate and basic rocks, showed inconclusive results. The volcanic rock data from the CAVA were used to successfully test these diagrams. The expected arc setting was consistently indicated for the CAVA from basic, intermediate, and acid rocks, confirming the satisfactory functioning of the diagrams. The data for all three types of rocks from the E-MVB and CAVA were then objectively compared for their similarities and differences. Specially designed computer programs were used to efficiently apply discordancy and significance tests at the strict 99% confidence level. Most (43 out of 50) chemical elements and (25 out of 28) log-ratio parameters in basic rocks from the E-MVB and CAVA showed statistically significant differences. For intermediate rocks and, to a lesser extent, for acid rocks, a large number of parameters also showed differences between the E-MVB and CAVA. The differences in the inferred tectonic settings for basic and evolved rocks from the E-MVB are likely related to the different magmatic sources.

“…a) San Nicolás; b) San Carlos. the recommendations of Aitchison (1986) as done by Verma et al (2006) for the first time for such applications in geosciences (see also Agrawal and Verma, 2007;Verma et al, 2013b;Verma and Armstrong-Altrin, 2013). The K 2 O and Rb contents in terrigenous sediments are sensitive to sedimentary recycling processes and have been widely used as indicators for source composition (Armstrong-Altrin et al, 2012;Tao et al, 2013 (Figure 9) reveals a compositional difference between the SN and SC sands and these ratios are higher in the SN sands (Table 1).…”

Section: Provenancementioning

confidence: 99%

“…These diagrams, though widely used ever since their proposal, do not incorporate a coherent statistical treatment of compositional data (Thomas and Aitchison, 2005;Agrawal and Verma, 2007;Verma, 2010Verma, , 2012Verma and Armstrong-Altrin, 2013). On the other hand, the use of these conventional discrimination diagrams has been cautioned against by many researchers (e.g., Armstrong-Altrin and Verma, 2005;Ryan and Williams, 2007).…”

Section: Tectonic Settingmentioning

confidence: 99%

Geochemistry of sands along the San Nicolás and San Carlos beaches, Gulf of California, Mexico: implications for provenance and tectonic setting

Armstrong‐Altrin¹,

Nagarajan²,

Lee³

et al. 2014

Self Cite

113

Th, P, and Hf were immobile and Cu, Cr, and Zn were mobile during alteration processes. However, Torres-Alvarado et al. (2007) recently studied the effect of hydrothermal alteration on the chemistry of volcanic rocks from the Los Azufres geothermal field, Mexico, and found that most major elements and a few trace elements, including high field strength elements such as Zr, Ti, and P, were mobilized during hydrothermal alteration. They cautioned against the use of these elements for petrogenetic studies of igneous and metamorphic rocks. Although provenance studies are common (Hossain et al., 2010(Hossain et al., , 2014Armstrong-Altrin and Natalhy-Pineda, 2013), studies focused on the geochemical variation in sediments with respect to grain size are meagre (e.g., Ohta, 2008;Effoudou-Priso, 2014).The study areas of the San Nicolás (SN) and San Carlos (SC) beaches are located along the Gulf of California.