Seismite in the Devonian Sultan Formation, Frenchman Mountain, Nevada: Evidence of far-field effect of the Alamo Event

2016 ◽  
Vol 53 (2) ◽  
pp. 93-114
Author(s):  
Jesús Pinto ◽  
John Warme
Keyword(s):  
Carbonate Platform ◽  
Far Field ◽  
Carbonate Sediments ◽  
Impact Event ◽  
Complex Matrix ◽  
Near Surface ◽  
Fault Block ◽  
Southern Nevada ◽  
Salt Pan ◽  
The Alamo

We interpret a discrete, anomalous ~10-m-thick interval of the shallow-marine Middle to Late Devonian Valentine Member of the Sultan Formation at Frenchman Mountain, southern Nevada, to be a seismite, and that it was generated by the Alamo Impact Event. A suite of deformation structures characterize this unique interval of peritidal carbonate facies at the top of the Valentine Member; no other similar intervals have been discovered in the carbonate beds on Frenchman Mountain or in equivalent Devonian beds exposed in ranges of southern Nevada. The disrupted band extends for 5 km along the Mountain, and onto the adjoining Sunrise Mountain fault block for an additional 4+km. The interval displays a range of brittle, ductile and fluidized structures, and is divided into four informal bed-parallel units based on discrete deformation style and internal features that carry laterally across the study area. Their development is interpreted as the result of intrastratal compressional and contractional forces imposed upon the unconsolidated to fully cemented near-surface carbonate sediments at the top of the Valentine Member. The result is an assemblage of fractured, faulted, and brecciated beds, some of which were dilated, fluidized and injected to form new and complex matrix bands between beds. We interpret that the interval is an unusually thick and well displayed seismite. Because the Sultan Formation correlates northward to the Frasnian (lower Upper Devonian) carbonate rocks of the Guilmette Formation, and the Guilmette contains much thicker and more proximal exposures of the Alamo Impact Breccia, including seismites, we interpret the Frenchman Mountain seismite to be a far-field product of the Alamo Impact Event. Accompanying ground motion and deformation of the inner reaches of the Devonian carbonate platform may have resulted in a fall of relative sea level and abrupt shift to a salt-pan paleoenvironment exhibited by the post-event basal beds of the directly overlying Crystal Pass Member.

Shocked quartz in the Alamo breccia, southern Nevada: Evidence for a Devonian impact event

Geology ◽  
1995 ◽  
Vol 23 (11) ◽  
pp. 1003 ◽  
Author(s):  
Hugues Leroux ◽  
John E. Warme ◽  
Jean-Claude Doukhan
Keyword(s):  
Impact Event ◽  
Southern Nevada ◽  
Shocked Quartz ◽  
The Alamo

The seafloor after a bolide impact: sedimentary and biotic signatures across the Late Devonian carbonate platform following the Alamo Impact Event, Nevada, USA

Facies ◽  
2014 ◽  
Vol 60 (2) ◽  
pp. 615-629 ◽  
Author(s):  
Leif Tapanila ◽  
Julia R. Steenberg ◽  
Carrie J. Johnson ◽  
Reed A. Myers
Keyword(s):  
Carbonate Platform ◽  
Late Devonian ◽  
Impact Event ◽  
The Alamo

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

IMPACT RESILIENCE: ECOLOGICAL RECOVERY OF A CARBONATE FACTORY IN THE WAKE OF THE LATE DEVONIAN IMPACT EVENT

Palaios ◽  
2020 ◽  
Vol 35 (1) ◽  
pp. 12-21
Author(s):  
BENJAMIN E. RENDALL ◽  
LEIF TAPANILA
Keyword(s):  
Marine Invertebrate ◽  
Depositional Environments ◽  
Ecological Resilience ◽  
Late Devonian ◽  
Impact Event ◽  
Geographic Ranges ◽  
Marine Communities ◽  
Before And After ◽  
The Alamo ◽  
The Impact

ABSTRACT Conformable limestone deposits bracketing the Alamo breccia (Late Devonian, Nevada) provide a robust dataset for comparisons of depositional environments and marine communities before and after a significant meteor impact. Rank abundances of more than 3000 faunal identifications from 158 sampling localities cluster in three major faunal groups that are arranged in an onshore-offshore lithofacies gradient. Comparison of faunal clusters before and after the impact show little to no dissimilarity. The recovery of marine invertebrate communities following the Alamo impact event was geologically instantaneous. Broad geographic ranges of the fauna may have contributed to ecological resilience. From a geologic perspective, marine communities appear to rebound quickly and fully following meteor impacts, leaving impact-related extinctions as outliers that correspond only to the largest impacts.

Rock Magnetic and Magnetostratigraphic Study of Chicxulub Crater Impact Breccias and Post-Impact Carbonates in the Yaxcopoil-1 and Santa Elena Boreholes

2020 ◽  
Author(s):  
Jaime Urrutia-Fucugauchi ◽  
Ligia Perez-Cruz ◽  
Elia Escobar-Sanchez ◽  
Miriam Velasco-Villarreal ◽  
Edgar Garcia-Garnica
Keyword(s):  
Oxygen Isotope ◽  
Carbonate Platform ◽  
Magnetic Hysteresis ◽  
Magnetization Vector ◽  
Carbonate Sediments ◽  
Carbon And Oxygen Isotope ◽  
Post Impact ◽  
Chicxulub Crater ◽  
The Impact ◽  
Santa Elena

<p>Chicxulub crater was formed ~66 Ma ago by an asteroid impact at the Cretaceous/Paleogene (K/Pg) boundary on the Yucatan carbonate platform in the southern Gulf of Mexico. The crater is the youngest and best preserved of the three large impact basins, with a ~200 km diameter and multi-ring and peak ring morphology. The crater, covered by post-impact carbonate sediments with thickness up to ~1.1 km, has been investigated by geophysical studies and drilling programs. Initial drilling in Yucatan was carried out by the Pemex oil company, followed by the National University UNAM Chicxulub program, the ICDP Yaxcopoil-1 project and the IODP-ICDP Expedition 364 marine drilling. Here, results of combined paleomagnetic, rock magnetic, petrographic and geochemical studies are used to characterize the sequence and constrain the unit’s emplacement and crater formation. We analyze core samples of suevitic breccias and Paleogene carbonates from the Yaxcopoil-1 and Santa Elena boreholes drilled in the southern sector, inside and to the south of the crater rim marked by the ring of cenotes.  Magnetic hysteresis, low-field susceptibility and coercitivity analyses indicate that main carriers are titanomagnetites and magnetite. Mineralogical and magnetic properties indicate effects of hydrothermal alteration, associated with the high temperature system generated by the impact. Higher coercitivity minerals are also observed in some samples. In the carbonate sections, hydrothermal effects as marked by the geochemical logs decrease upwards from the breccia-carbonate contact. Alternating field and thermal demagnetization is used to investigate the magnetization vector composition and isolate the characteristic remanent components. Magnetic polarities defined from the inclination data show a sequence of reverse to normal, which correlate to polarity chrons 29r to 26r, with impact occurring within 29r chron.  The correlations of the magnetostratigraphy and stable isotopes indicate a hiatus at the basal Paleocene section. In Santa Elena cores, d<sup>13</sup>C values range from 1.2 to 3.5%<sub>0 </sub>and d<sup>18</sup>O values range from -1.4 to -4.8%<sub>0, </sub>with variation trends correlating with the marine carbon and oxygen isotope records for the late Maastrichtian and early Paleocene. The positive carbon isotopes indicate high productivity after the K/Pg extinction event, while the oxygen isotope values are more negative reflecting regional and local effects. Silica contents decrease from high in the suevites to low values in carbonates showing higher variability and then increased contents at the Paleocene-Eocene Thermal Maximum (PETM). The geochemical trends correlate in other elements including iron, titanium, potassium and aluminum that record impact-induced hydrothermal effects and possibly changing depositional conditions. Ca shows an opposite trend, with lower values in the upper suevitic breccias, higher values in the Paleocene carbonates and lower values in the PETM.</p>

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

scholarly journals Calpionellid biostratigraphy and microfacies analysis of a Tithonian–Berriasian carbonate succession in the Western Srednogorie (Bulgaria)

2017 ◽  
Vol 46 (1) ◽  
pp. 65-92
Author(s):  
Silviya Petrova ◽  
Polina Andreeva ◽  
Lubomir Metodiev ◽  
Daniela Reháková ◽  
Jozef Michalík ◽  
...  
Keyword(s):  
Carbonate Platform ◽  
Carbonate Sediments ◽  
Marine Environments ◽  
Microfacies Analysis ◽  
Diagnostic Features ◽  
Depositional Settings ◽  
Lithostratigraphic Units

In the eastern part of the Western Srednogorie Unit, around Dragovishtitsa Village, a specific succession of the Gintsi and Glozhene–Slivnitsa formations has provided micropalaeontological evidence for late Tithonian (Chitinoidella, Praetintinnopsella and the base of Crassicollaria zones) and mid-Berriasian (the Elliptica Subzone of the Calpionella Zone) age on the basis of 45 chitinoidellid and calpionellid species. A significant stratigraphic hiatus is documented within the Glozhene–Slivnitsa Formation, since a part of the Crassicollaria Zone, as well as the Alpina+Remaniella subzones of the Calpionella Zone, is absent from the Dragovishtitsa 1 section. The conformably overlying Salash Formation is of mid-Berriasian age (Elliptica Subzone) and is locally characterized by the presence of calcareous sandstones (Dragovishtitsa 2 section). The Salash–Cherni Osam Formation, as well as the clayey limestone unit covering the Slivnitsa Formation, is also of mid-Berriasian age (Elliptica Subzone). The Slivnitsa and Glozhene–Slivnitsa formations, which underlie the Salash–Cherni Osam Formation in the Dragovishtitsa East section, correspond to the Crassicollaria Zone and the Alpina Subzone, respectively. Reworking of calpionellids from the Crassicollaria Zone is documented in the Alpina and Elliptica subzones in all three studied sections. Eight microfacies types are distinguished, which suggests that the carbonate sediments were deposited in a carbonate platform rather than in a pelagic basin environment, althought the upper part of the studied sections reveals an upward-deepening trend. The Slivnitsa Formation is covered by highly diachronous sediments from more distal settings: from mid-Berriasian around Dragovishtitsa Village to the Berriasian/Valanginian transition at the Tri Ushi section to late Valanginian in the Dragoman and Kalotina sections. This fact, together with the significant stratigraphic hiatus within the Glozhene–Slivnitsa Formation, is interpreted here as tectonically controlled. The presence of transitional depositional settings from carbonate platform to deeper-marine environments caused deposition of specific lithostratigraphic units not always corresponding to the diagnostic features of the Glozhene, Salash and Cherni Osam formations.

scholarly journals An Attempt for Construction of Carbonate Platform Geometry from Devonian Hajigak Formation, Central Afghanistan, with the Help of Facies Analysis and Petrography

2021 ◽  
Vol 3 (31) ◽  
pp. 49-73
Author(s):  
Mohammad Sarwary ◽  
◽  
Mirza AmirkhaniT ◽  
Hassan Malistani ◽  
◽  
...  
Keyword(s):  
Facies Analysis ◽  
Carbonate Platform ◽  
Carbonate Sediments ◽  
Two Systems ◽  
The Subject ◽  
Siliciclastic Sediments ◽  
Two Sectors ◽  
Mixed Carbonate

The subject of sedimentology fundamentally remained subdivided into two sectors viz. siliciclastic and carbonate with the understanding that these two systems are mutually dissociative in terms of their genesis. Even in the highly referred textbooks, siliciclastics and carbonates are always discussed in separate sections. Presumably, the limited occurrences of mixed siliciclastic-carbonate sediments in nature are because of constraining effects that siliciclastics have on carbonate-secreting organisms; the two sediments rarely found mutually associated in nature. Although the mixed carbonate-siliciclastic sediments are subordinate in occurrence, their presence in some instances proved that they do not represent any geological oddity. Rather, their sediment logical history may tell us a great deal about the dynamics and interactions of facies, paleoecologies of many carbonate-secreting organisms, and tectonic histories of depositional basins. Keeping this in mind, the present study attempted to recognize and draw the paleoenvironmental conditions and processes of the Devonian Hajigak Formation, Afghanistan by means of detailed facies analysis and petrographical signatures. An attempt has also been made to characterize sandstone wedges that punctuate the carbonate succession and some variable deposits of shales and marls.

Study of geodynamic situation cut off parts of the plots using ergonometry with the open method of field development

2020 ◽  
pp. 46-55
Author(s):  
T. Sh. Dalatkazin ◽  
P. I. Zuev
Keyword(s):  
Safety Margin ◽  
Discrete Distribution ◽  
Coarse Grained ◽  
Open Pit ◽  
Carbonate Sediments ◽  
Coal Deposit ◽  
Near Surface ◽  
Field Development ◽  
Deformation Processes ◽  
Geodynamic Activity

Modern methods for calculating the safety factor of the sides of the open pit do not take into account the parameters of the modern geodynamic activity of the instrument array. The article presents the results of the first stage of research on the unique capabilities of radonometry to solve this problem. The studies were carried out in the instrument areas of the Shubarkol coal deposit. Terrigenous-carbonate sediments represented by fine and coarse-grained sandstones, siltstones, mudstones, loamy rocks and coals take part in the geological structure of the deposit. The stress-strain state of the rock massif in the area of the Shubarkulsky coal deposit is very heterogeneous. The nature of the deformation processes of the sides of the section is constant and moderate. Here, a discrete distribution of deformation sections is characteristic. The article presents the methods of radonometric measurements, the processing of measurement results and the results of studies of the near-surface sections of a coal mine, aimed at developing a methodology for quantitatively taking into account the degree of modern geodynamic activity in the design of open pit sides. Based on the results of radonometry, the geodynamic activity indices identified in the study of the deformation zones of the instrumentation areas are determined. An algorithm for further studies of the problem of taking into account the degree of modern geodynamic activity in determining the safety margin of open pit sides is determined.The accumulation and generalization of empirical information about the deformation processes of open pits and the results of studies of the geodynamic situation of dash sites, determined using radonometry, will make it possible to modernize the methodology for calculating the margin of safety margin of the sides.

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