Outcrop-based characterization of the Leonardian carbonate platform in west Texas: Implications for sequence-stratigraphic styles in the Lower Permian

AbstractThe Permian is regarded as one of the most crucial intervals during echinoid evolution because crown group echinoids are first widely known from the Permian. New faunas provide important information regarding the diversity of echinoids during this significant interval as well as the morphological characterization of the earliest crown group and latest stem group echinoids. A new fauna from the Capitanian Lamar Member of the Bell Canyon Formation in the Guadalupe Mountains of West Texas comprises at least three new taxa, includingEotiaris guadalupensisThompson n. sp. an indeterminate archaeocidarid, andPronechinus? sp. All specimens represented are silicified and known from disarticulated or semiarticulated interambulacral and ambulacral plates and spines. This assemblage is one of the most diverse echinoid assemblages known from the Permian and, as such, informs the paleoecological setting in which the earliest crown group echinoids lived. This new fauna indicates that crown group echinoids occupied the same environments as stem group echinoids of the Archaeocidaridae and Proterocidaridae. Furthermore, the echinoids described herein begin to elucidate the order of character transitions that likely took place between stem group and crown group echinoids. At least one of the morphological innovations once thought to be characteristic of early crown group echinoids, crenulate tubercles, was in fact widespread in a number of stem group taxa from the Permian as well. Crenulate tubercles are reported from two taxa, and putative cidaroid style U-shaped teeth are present in the fauna. The presence of crenulate tubercles in the archaeocidarid indicates that crenulate tubercles were present in stem group echinoids, and thus the evolution of this character likely preceded the evolution of many of the synapomorphies that define the echinoid crown group.

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Regional Seismic Characterization of Shallow Subsoil of Northern Apulia (Southern Italy)

Geosciences ◽

10.3390/geosciences11100416 ◽

2021 ◽

Vol 11 (10) ◽

pp. 416

Author(s):

Enrico Paolucci ◽

Giuseppe Cavuoto ◽

Giuseppe Cosentino ◽

Monia Coltella ◽

Maurizio Simionato ◽

...

Keyword(s):

Southern Italy ◽

Carbonate Platform ◽

Low Cost ◽

Principal Component ◽

Ambient Vibration ◽

Resonance Effects ◽

Resonance Phenomena ◽

Single Station ◽

Seismic Characterization

A first-order seismic characterization of Northern Apulia (Southern Italy) has been provided by considering geological information and outcomes of a low-cost geophysical survey. In particular, 403 single-station ambient vibration measurements (HVSR techniques) distributed within the main settlements of the area have been considered to extract representative patterns deduced by Principal Component Analysis. The joint interpretation of these pieces of information allows the identification of three main domains (Gargano Promontory, Bradanic Through and Southern Apennines Fold and Thrust Belt), each characterized by specific seismic resonance phenomena. In particular, the Bradanic Through is homogeneously characterized by low frequency (<1 Hz) resonance effects associated with relatively deep (>100 m) seismic impedance, which is contrasting corresponding to the buried Apulian carbonate platform and/or sandy horizons located within the Plio-Pleistocene deposits. In the remaining ones, relatively high frequency (>1 Hz) resonance phenomena are ubiquitous due to the presence of shallower impedance contrasts (<100 m), which do not always correspond to the top of the geological bedrock. These general indications may be useful for a preliminary regional characterization of seismic response in the study area, which can be helpful for an effective planning of more detailed studies targeted to engineering purposes.

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CHARACTERIZATION OF LOWER PERMIAN CARBONATE SUBAQUEOUS GRAVITY FLOWS IN CROCKETT COUNTY, TEXAS

10.1130/abs/2016sc-273858 ◽

2016 ◽

Author(s):

Wesley Turner ◽

Keyword(s):

Lower Permian ◽

Gravity Flows

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Seismic characterisation of carbonate platforms and reservoirs: an introduction and review

Geological Society London Special Publications ◽

10.1144/sp509-2021-51 ◽

2021 ◽

pp. SP509-2021-51

Author(s):

J. Hendry ◽

P. Burgess ◽

D. Hunt ◽

X. Janson ◽

V. Zampetti

Keyword(s):

Seismic Data ◽

Large Scale ◽

Carbonate Platform ◽

Energy Transition ◽

Carbonate Platforms ◽

Seismic Attribute ◽

Sequence Stratigraphic ◽

3D Data ◽

Diagenetic Facies ◽

Central Atlantic

AbstractImproved seismic data quality in the last 10–15 years, innovative use of seismic attribute combinations, extraction of geomorphological data, and new quantitative techniques, have significantly enhanced understanding of ancient carbonate platforms and processes. 3D data have become a fundamental toolkit for mapping carbonate depositional and diagenetic facies and associated flow units and barriers, giving a unique perspective how their relationships changed through time in response to tectonic, oceanographic and climatic forcing. Sophisticated predictions of lithology and porosity are being made from seismic data in reservoirs with good borehole log and core calibration for detailed integration with structural, paleoenvironmental and sequence stratigraphic interpretations. Geologists can now characterise entire carbonate platform systems and their large-scale evolution in time and space, including systems with few outcrop analogues such as the Lower Cretaceous Central Atlantic “Pre-Salt” carbonates. The papers introduced in this review illustrate opportunities, workflows, and potential pitfalls of modern carbonate seismic interpretation. They demonstrate advances in knowledge of carbonate systems achieved when geologists and geophysicists collaborate and innovate to maximise the value of seismic data from acquisition, through processing to interpretation. Future trends and developments, including machine learning and the significance of the energy transition, are briefly discussed.

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