Using Geochemical Data To Understand Geological Processes

[Shantelle Wenske]

Thistextbook is a complete rewrite, and expansion of Hugh Rollinson's highly successful 1993 book Using Geochemical Data: Evaluation, Presentation, Interpretation. Rollinson and Pease's new book covers the explosion in geochemical thinking over the past three decades, as new instruments and techniques have come online. It provides a comprehensive overview of how modern geochemical data are used in the understanding of geological and petrological processes. It covers major element, trace element, and radiogenic and stable isotope geochemistry. It explains the potential of many geochemical techniques, provides examples of their application, and emphasizes how to interpret the resulting data. Additional topics covered include the critical statistical analysis of geochemical data, current geochemical techniques, effective display of geochemical data, and the application of data in problem solving and identifying petrogenetic processes within a geological context. It will be invaluable for all graduate students, researchers, and professionals using geochemical techniques.

Fossils are the preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud, under ancient seas, lakes and rivers. Fossils also include any preserved trace of life that is typically more than 10 000 years old.

Soft body parts decay soon after death, but the hard parts, such as bones, shells and teeth can be replaced by minerals that harden into rock. In very exceptional cases, soft parts like feathers, plant ferns or other evidence of life, such as footprints or dung, may also be preserved. Remains can include microscopically small fossils, such as single-celled foraminifera or pollen grains, as well as more familiar fossils such as ammonites and trilobites.

Fossils give us a useful insight into the history of life on Earth. They can teach us where life and humans came from, show us how the Earth and our environment have changed through geological time, and how continents, now widely separated, were once connected.

Fossils can also be used to date rocks. Through the process of evolution, different kinds of fossils occur in rocks of different ages, enabling geologists to use fossils to understand geological history. For geologists, fossils are one of the most important tools for age correlation. Ammonites, for example, make excellent guide fossils for stratigraphy; they can be used to determine the relative age of two or more layers of rock, or strata, that are in different places within the same country or somewhere else in the world.

Fossils are typically found in sedimentary rocks and occasionally some fine-grained, low-grade metamorphic rocks. Sometimes the fossils have been removed, leaving moulds in the surrounding rock, or the moulds may have later been filled by other materials, forming casts of the original fossils.

Rapid burial by sediments that were previously suspended in water is required for fossilisation to occur. The burial process isolates the remains from the biological and physical processes that would otherwise break up or dissolve the body material.

Fossils are more likely to be preserved in marine environments for example, where rapid burial by sediments is possible. Less favourable environments include rocky mountaintops where carcasses decay quickly or few sediments are being deposited to bury them.

Some fossils form when their remains are compressed at depth. A dark imprint of the fossil is produced as a result of high-pressure forces exerted by the weight of overlying sediments and perhaps sea water.

Plant leaves and ferns are good examples of fossils produced by compression. This image shows Coniopteris, which is a type of true fern, or pteropsid, fossil from the Jurassic Period. More about fossil plants. BGS UKRI.

In cases where the original shell or bone is dissolved away, it may leave behind a space in the shape of the original material called a mould. At some point in the future, sediments may fill the space to form a matching cast. Soft-bodied sea creatures such as snails are commonly found as moulds and casts because their shells dissolve easily. A cast is a positive impression of the original material formed by contact with the mould. More about gastropods.

This image is a mould of an ancient snail or slug called Bellerophon, a gastropod. Fossils can form when mould of the interior of the shell is made by water-borne minerals percolating through it, but later the shell material dissolves away. BGS UKRI.

The rarest form of fossilisation is the preservation of original skeletons and soft body parts. Insects that have been trapped and preserved perfectly in amber (fossilised tree resin) are examples of preserved remains.

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited. For more information, please refer to

Feature papers represent the most advanced research with significant potential for high impact in the field. A Feature Paper should be a substantial original Article that involves several techniques or approaches, provides an outlook for future research directions and describes possible research applications.

Abstract: Archaeoseismological research often deals with two unresolved questions: the magnitude and level of damage caused by past earthquakes, and the precise location of the seismic source. We propose a comprehensive review of an integrated approach that combines site effects with the analysis of geochemical data in the field of archaeoseismology. This approach aims to identify active buried faults potentially related to the causative seismic source and provide insights into earthquake parameters. For each integrated method, we report the foundational principles, delineation of theoretical field procedures, and exemplification through two case studies. Site effects analysis in archaeoseismology assumes a pivotal role in unraveling historical seismic occurrences. It enables estimating the earthquake magnitude, assessing the seismotectonic patterns, and determining the resulting damage level. Valuable data related to earthquake parameters can be extracted by analyzing vibration frequencies and acceleration measurements from structures within archaeological sites. This information is instrumental in characterizing seismic events, evaluating their impact on ancient structures, and enhancing our understanding of earthquake hazards within the archaeological context. Geochemical investigations supply indispensable tools for identifying buried active faults. The analysis of fluids and gases vented in proximity to faults yields valuable insights into their nature, activity, and underlying mechanisms. Faults often manifest distinctive geochemical imprints, enabling the differentiation between tectonically active and volcanically related fault systems. The presence of specific gases can further serve as indicators of the environmental conditions surrounding these fault networks. Integrating site effects analysis and geochemical investigations within archaeoseismological research is crucial to improving our understanding of unknown past earthquakes. Moreover, it enhances the seismic hazard assessment of the region under study. Keywords: archaeoseismology; local site effects; earthquake parameters; geochemical investigation; buried active fault

Bottari, Carla, Patrizia Capizzi, and Francesco Sortino. 2024. "Unraveling the Seismic Source in Archaeoseismology: A Combined Approach on Local Site Effects and Geochemical Data Integration" Heritage 7, no. 1: 427-447.

Since 2009, the MSRL mission and workflow has improved our knowledge of reservoir characterization and the stratigraphic framework of mudrock systems by integrating core measurements, fluid saturations, fluid flow modeling, and petrophysics. Multidisciplinary in nature, MSRL studies are applied to understand geological heterogeneities in the subsurface across oil and gas reservoirs by an integrated approach of geology, geochemistry, petrophysics and well logging. MSRL research is closely aligned with exploration, drilling and completions, and understanding key processes that control reservoir quality and fluid properties.

The MSRL workflow is designed to generate high quality data, validate externally derived datasets, and understand key processes that control reservoir quality. MSRL researchers maintain geochemistry, petrophysics, and scanning electron microscopy laboratories to support our research projects.

MSRL research is multidisciplinary and integrates data generated from the MSRL core characterization laboratories to build core-validated geological models. We are focused on understanding key processes that control fluid flow and porosity in mudrock systems, which requires viewing rocks using scanning electron microscopy. Pore-scale studies are integrated with basin scale studies through geological characterizations at the core- and wireline-scale.

Dynamic and static characterizations of fluid flow and the integration of geological controls are accomplished through innovative imaging techniques. Petrophysical measurements (porosity, permeability, relative permeability) are combined with imaging to provide a unique approach to understand fluid flow in shale.

The MSRL maintains a database of core-based and wireline log measurements from major mudrock plays across the United States, China, and Argentina. We apply these data to our multi-disciplinary approach to better understand reservoir characteristics that affect the reservoir quality of mudrock petroleum systems.

3a8082e126