TECTONIC EVENTS AND EUSTATIC CYCLE CORRELATION: A REVIEW OF BIOSTRATIGRAPHIC ISSUES FOR DEPOSITIONAL CYCLE CHART CONSTRUCTION AND SEQUENCE DATING

2019 ◽  
pp. 94-107
Keyword(s):  
Tectonic Events ◽  
Depositional Cycle

scholarly journals Helium in diamonds unravels over a billion years of craton metasomatism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yaakov Weiss ◽  
Yael Kiro ◽  
Cornelia Class ◽  
Gisela Winckler ◽  
Jeff W. Harris ◽  
...  
Keyword(s):  
Continental Lithosphere ◽  
Late Mesozoic ◽  
Tectonic Events ◽  
Upper Limit ◽  
Age Limits ◽  
Fluid Bearing ◽  
Major Surface ◽  
Chemical Events

AbstractChemical events involving deep carbon- and water-rich fluids impact the continental lithosphere over its history. Diamonds are a by-product of such episodic fluid infiltrations, and entrapment of these fluids as microinclusions in lithospheric diamonds provide unique opportunities to investigate their nature. However, until now, direct constraints on the timing of such events have not been available. Here we report three alteration events in the southwest Kaapvaal lithosphere using U-Th-He geochronology of fluid-bearing diamonds, and constrain the upper limit of He diffusivity (to D ≈ 1.8 × 10−19 cm2 s−1), thus providing a means to directly place both upper and lower age limits on these alteration episodes. The youngest, during the Cretaceous, involved highly saline fluids, indicating a relationship with late-Mesozoic kimberlite eruptions. Remnants of two preceding events, by a Paleozoic silicic fluid and a Proterozoic carbonatitic fluid, are also encapsulated in Kaapvaal diamonds and are likely coeval with major surface tectonic events (e.g. the Damara and Namaqua–Natal orogenies).

Cerro del Hierro, Spain: the largest exposed early Cambrian palaeokarst

2020 ◽  
pp. 1-14
Author(s):  
Eduardo Mayoral ◽  
María Eugenia Dies Álvarez ◽  
José Antonio Gámez Vintaned ◽  
Rodolfo Gozalo ◽  
Eladio Liñán ◽  
...  
Keyword(s):  
South America ◽  
Mediterranean Region ◽  
Early Cambrian ◽  
Karst Development ◽  
Global Context ◽  
Tectonic Events ◽  
Extensional Tectonic ◽  
Geomorphological Processes ◽  
The Uk ◽  
Regressive Events

Abstract We study the largest exposed example of an early Cambrian palaeokarst, associated with laterites and developed during rifting of the Ossa–Morena Zone. The lithostratigraphy, biostratigraphy, facies and the genesis reflect episodes of sea-level fall (Cerro del Hierro Regression) related to tectonic events and palaeoclimate. This palaeokarst can be primarily considered as the result of early Cambrian polyphase karstification in an extensional tectonic regime, later modified by Neogene–Quaternary geomorphological processes. The event may correlate with other regressive events of a similar age in Spain, Italy, United Kingdom, South America and Australia. This episode also has local names (e.g. Cerro del Hierro Regression in the Mediterranean region; Woodlands Regression in the UK). It is sometimes accompanied by additional karst development outside of Spain that is compared and interpreted in a global context.

Tectonic events of Late Proterozoic-Triassic in South China

1991 ◽  
Vol 6 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Wan Tianfeng ◽  
Zhu Hong
Keyword(s):  
South China ◽  
Late Proterozoic ◽  
Tectonic Events

Status of the Jurassic in the Canadian Cordillera of British Columbia, Alberta, and southern Yukon

1970 ◽  
Vol 7 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Hans Frebold ◽  
H. W. Tipper
Keyword(s):  
British Columbia ◽  
Fossil Record ◽  
Canadian Cordillera ◽  
Tectonic Events ◽  
Source Of Information

Jurassic index fossils of the Canadian Cordillera indicate the presence of some zones of most Jurassic stages. In this report the more important localities are listed, the source of information, published and unpublished, is indicated, and an up-dated correlation chart is presented. The importance of tectonic events and their effect on the completeness of the Jurassic fossil record and on the Jurassic paleogeography are stressed.

Late Ordovician to Early Silurian Tectonic Events in the Himalayan Terrain

2016 ◽  
Vol 90 (3) ◽  
pp. 1049-1050
Author(s):  
GAO Li'e ◽  
ZENG Lingsen ◽  
HU Guyue ◽  
WANG Yuhua ◽  
GAO Jiahao ◽  
...  
Keyword(s):  
Late Ordovician ◽  
Tectonic Events

Performance of a rotational sensor at Etna, Italy focusing on back-azimuth estimations of volcano-seismic events

2021 ◽  
Author(s):  
Martina Rosskopf ◽  
Eva P. S. Eibl ◽  
Gilda Currenti ◽  
Philippe Jousset ◽  
Joachim Wassermann ◽  
...  
Keyword(s):  
Rotation Rate ◽  
Mount Etna ◽  
Seismic Events ◽  
Volcano Seismology ◽  
Rotational Seismology ◽  
Long Period ◽  
Tectonic Events ◽  
Back Azimuth ◽  
Seismic Wavefield

<p>The field of rotational seismology has only recently emerged. Portable 3 component rotational sensors are commercially available since a few years which opens the pathway for a first use in volcano-seismology. The combination of rotational and translational components of the wavefield allows identifying and filtering for specific seismic wave types, estimating the back azimuth of an earthquake, and calculating local seismic phase velocities.</p><p>Our work focuses on back-azimuth calculations of volcano-tectonic and long-period events detected at Etna volcano in Italy. Therefore, a continuous full seismic wavefield of 30 days was recorded by a BlueSeis-3A, the first portable rotational sensor, and a broadband Trillium Compact seismometer located next to each other at Mount Etna in August and September of 2019. In this study, we applied two methods for back-azimuth calculations. The first one is based on the similarity of the vertical rotation rate to the horizontal acceleration and the second one uses a polarization analysis from the two horizontal components of the rotation rate. The estimated back-azimuths for volcano-tectonic events were compared to theoretical back-azimuths based on the INGV event catalog and the long-period event back-azimuths were analyzed for their dominant directions. We discuss the quality of our back azimuths with respect to event locations and evaluate the sensitivity and benefits of the rotational sensor focusing on volcano-seismic events on Etna regarding the signal to noise ratios, locations, distances, and magnitudes.</p>

Lineaments Revisited

SEG Discovery ◽  
2000 ◽  
pp. 1-20
Author(s):  
JEREMY P. RICHARDS
Keyword(s):  
Large Scale ◽  
Mineral Exploration ◽  
Porphyry Copper ◽  
Regional Scale ◽  
Tectonic Events ◽  
Magma Reservoirs ◽  
Magma Supply ◽  
Magmatic History ◽  
Lithospheric Stress ◽  
Crustal Magma

ABSTRACT Large-scale crustal lineaments are recognized as corridors (up to 30 km wide) of aligned geological, structural, geomorphological, or geophysical features that are distinct from regional geological trends such as outcrop traces. They are commonly difficult to observe on the ground, the scale of the features and their interrelationships being too large to map except at a regional scale. They are therefore most easily identified from satellite imagery and geophysical (gravity, magnetic) maps. Lineaments are believed to be the surface expressions of ancient, deep-crustal or trans-lithospheric structures, which periodically have been reactivated as planes of weakness during subsequent tectonic events. These planes of weakness, and in particular their intersections, may provide high-permeability channels for ascent of deeply derived magmas and fluids. Optimum conditions for magma penetration are provided when these structures are placed under tension or transtension. In regions of subduction-related magmatism, porphyry copper and related deposits may be generated along these lineaments because the structures serve to focus the ascent of relatively evolved magmas and fluid distillates from deep-crustal magma reservoirs. However, lineament intersections can only focus such activity where a magma supply exists, and when lithospheric stress conditions permit. A comprehensive understanding of regional tectono-magmatic history is therefore required to interpret lineament maps in terms of their prospectivity for mineral exploration.

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