Any component of geologic science that is up for discussion in a court of law is deemed to be forensic geology. To identify and assess geologic materials that might be connected to forensic issues, forensic geology employs the guiding principles of the geologic sciences. These ideas are also used by forensic geologists to determine the proper geologic setting for a forensic scene or site. Forensic geology covers the assessment and justification of compliance with policies, norms, and ethics about professional conduct.
Involvement as an expert witness and the giving of expert testimony regarding the geologic activity or circumstance are all included in forensic geology. Geologists who operate in forensic settings must be familiar with the legal principles that govern those settings, such as legal sufficiency, evidence chain of custody, and procedures for gathering, preserving, and validating evidence. Geologic science can be useful in addressing a variety of issues and challenges that law enforcement and forensic specialists frequently encounter. Even if forensic geology is unlikely to become a well-known sub-discipline of geologic research shortly, law enforcement officials and geologists themselves will be able to see how it contributes to the resolution of several forensic issues.
Geology is the study of the origin, evolution, processes, and materials of the earth. Investigating earth processes and materials for a legal purpose is the focus of forensic geology. Any part of geologic science that is raised for discussion in a court of law is considered forensic geology. The following inquiries, which have both geologic and legal ramifications, highlight the extent of forensic geology:
• What is this substance?
• From where did this information come?
• Is it—or could it be—specific to a crime scene or the circumstances surrounding a criminal act?
• What is the crime scene’s geologic background, and what implications does it have on the containment, preservation, and recovery of evidence—possibly including weapons, human remains, and personal effects?
• How will the geologic setting of a forensic site or prospective forensic site affect the approaches taken to deal with the forensic issues raised by the site?
• How do the conditions and circumstances of burial connect to the geologic features of a secret gravesite?
• Is it possible to more accurately delineate a secret grave in an unobtrusive, non-destructive way?
• In the geology elements of a particular project or problem, were acknowledged, ethical standards and procedures used?
The direct application of geologic ideas, methods, and procedures to a variety of forensic difficulties and legal challenges constitutes the practical part of forensic geology. The concepts on which geologic research is built are supported, expanded, and helped define in part through collaboration with other scientific disciplines. A multitude of technical and scientific disciplines are involved in the solution of each forensic issue, and forensic geology is no different in this regard.
When identifying and describing materials, for example, the final answer to a forensic query may be unmistakably and categorically geologic in nature. In other situations, such as the search for a hidden grave or buried evidence, geology may help solve a forensic puzzle or provide the answer to a forensic question. In these situations, geophysics, remote sensing, image analysis, botany, entomology, canine sweep, or witness interrogation all play crucial roles. The interpretation and application of recognized professional codes of ethical practices and standards of performance under forensic circumstances and contention are also included in the field of forensic geology.
Such norms, processes, and standards as applied generally to the earth sciences are defined, supported, and in some circumstances, revised and modified by expert testimony and legal discussion.
Science has always been viewed with a physics bias, emphasizing experimentation, quantification, and prediction as its core values. Geology, on the other hand, is usually conceptual, observational, and primarily descriptive. It is an intellectual and philosophical science. The 4.6 billion-year-old age of the world and the vast amounts of time that all earthly processes take place in represent the fundamental concerns of science with profound and abundant time.
Geology’s unwavering assumption of profound time prevents a thorough and conclusive characterization of occurrences that took place a very long time ago. Since the time context of the most fundamental geologic processes, events, and phenomena cannot be effectively represented or otherwise incorporated into the experimental process, rigorous experimentation is likewise generally absent from geology’s scientific methodology. Geologic explanations frequently have a more probabilistic nature, and hence, geologic conclusions frequently have a probabilistic nature as well. This is not to argue that certain elements of the geologic sciences, such as geophysics, petrophysics, geochemistry, and geostatistics, cannot be quantified and are the subject of rigorous and fruitful research.
The regularity of processes over a long period is yet another basic problem in geologic science. “Uniformitarianism” is the term used to describe the fundamental principle of process uniformity over time. According to uniformitarianism, the physical and chemical processes that are currently shaping and altering the world have operated in the same way throughout the planet’s history. Additionally, it is believed that these processes are adequate to explain all geologic changes. In summary, uniformitarianism holds that the earth’s crustal plates have always drifted with time, water has always flowed downhill, sedimentary layers have always been deposited horizontally, and space debris has always affected the earth’s surface.
The application of the geologic sciences to forensic issues and situations is largely based on these ideas and precepts. The retrieval and preservation of physical evidence at a forensic site or crime scene are guided by these principles, among others. The characterization and understanding of the contextual relationship between retrieved evidence and its setting of deposition and manner of occurrence are based on these concepts, which offer the conceptual foundation. The evaluation and interpretation of laboratory investigations of geologic materials that reflect on the overall context or setting of a specific forensic site or forensic event are likewise based on these concepts.
Geologists and other field scientists, such as archaeologists, anthropologists, botanists, and even crime scene investigators, use similar fundamental field methodologies. The few differences that do exist tend to be philosophical or to center on the distinctive intellectual tenets of a given field. The location of the site of the activity inside three-dimensional space, which is typically represented as some kind of map, maybe a primary concern of many forensic issues. The mapping of a forensic site can take many different forms, from a straightforward sketch to a very precise topographic map created following strict surveying guidelines.
No matter how crude, a map must have recoverable or distinguishable reference points for both horizontal and vertical control, a north arrow or another orientation indicator, and a scale, however imperfect. Any map should be properly dated, include details on the circumstances surrounding its compilation, and list the compiler(s)’ names. The mapping of problem regions makes excellent use of existing topographic maps, such as those released by the United States Geological Survey. Many of these topographic maps are now offered in hard copy and digital formats. Professional topographers and surveyors can also create precise scene maps on the spot, if necessary.
Determine the position of a certain spot using aerial photos or hybrid topographic maps with a photographic base.
To address issues brought up by the legal system, forensic geology is the examination of evidence linked to minerals, oil, petroleum, and other materials found on Earth. Forensic Geology was published in 1975 by Ray Murray and John Tedrow, two other professors from Rutgers University.
Today, trace evidence is the primary use of forensic geology. To be able to connect a suspect to a specific incident or location, soil and sediment particulate’s must be examined. Theft, fraud, discovering a gravesite, and other applications are possible in this scientific discipline.
It needs the assistance of numerous other scientific fields, including engineering, biology, geography, medicine, and many others.
A book called Geoforensics, written in 2008 by Queen’s University Belfast professors Alastair Ruffell and Jennifer McKinley focuses more on using geomorphology and geophysics for searches. 2010 saw chapters for the textbook Criminal and Environmental Soil Forensics co-edited by James Hutton Institute forensic soil expert Lorna Dawson. An Introduction to Forensic Geoscience, written by Elisa Bergslien of SUNY Buffalo State, was released in 2012 as a general textbook on the subject.
In geomorphology, landforms are studied. The geomorphology of a forensic site is essential to “the lay of the land” and what determines the topography and drainage of the land surface. Land use, surface drainage, and groundwater flow strength and direction are frequently controlled by geomorphology. Geomorphology regulates point-to-point visibility, but vegetative cover frequently reduces it. Understanding the geomorphology of a region can be greatly aided by topographic maps, aerial photographs, fixed- or rotary-winged aircraft overflights, road reconnaissance, and ground traversing.
Point-to-point visibility and access may be important location criteria in covert grave searches. Understanding the geomorphologic context of a region can aid in concentrating the ground search required by a variety of forensic situations.
Usage of forensic geology in the past
Murray claims that Sir Arthur Conan Doyle, the author of Sherlock Holmes, is the father of forensic geology. The fictional detective Sherlock Holmes claimed to be able to track down a person’s location using a variety of techniques, such as by studying London’s exposed geology to the point that he could recognize certain clays on a person’s shoe. Most likely the first person to employ soil analysis to connect suspects to a crime scene was Georg Popp of Frankfurt, Germany.
In 1891, Hans Gross used microscopic analysis of soils and other materials from a suspect’s shoes to link him to the crime scene.
Two different types of soil samples are used in forensic geology applications. The first is the questioned sample—samples whose provenance is unknown. These kinds of samples can, for instance, be obtained from a person’s shoe. The forensic geologist can select a control sample as the other type of sample. Soil collected from the crime scene would be the most typical control sample. The comparison of the questioned and control samples would then be used to determine any similarities or differences between them.
Regarding the evidence gathering from a questioned sample, these samples were probably obtained accidentally. For instance, a suspect can have dirt or rocks in their clothes or shoes.
Due to this, the forensic geologist has no control over the sample’s size, and, likely, it will not be equivalent to the control sample in size. The best method to compare the question sample to the control sample will depend on the question sample, thus the forensic geologist will need to exercise professional judgment. Only loose particles are accessible for comparison in some circumstances. If the sample in question is discovered to be a lump of soil, the entire lump must be collected to preserve the various soil layers within the lump as well as maintain the particles. In the field, techniques including applying the adhesive tape, vacuuming, and shaking objects over a tarp are also employed.
Samples from the scene or an alibi site are two of the subcategories of controlled samples. The questioned sample should be studied first to determine the particle size, color, or any other identifiable factors before carefully selecting a position at the scene to sample in contrast. Soil samples might vary from a very little distance. The forensic lab can also receive samples taken from these scenes together with other pieces of tangible evidence. Depending on the lab, the collector would receive specific instructions on how to gather and submit the sample. When taking soil samples from the earth, it is advised to take samples from the horizon and bed layers, among other soil layers.
It’s crucial to collect samples with a range of colors, textures, and mineral composition.
Depending on the type of sample—questioned or controlled—as well as its structure and size, the instruments employed to gather evidence vary. Using forceps, tweezers, palette knives, etc., smaller amounts of soil can be removed. An ice pick, razor blade, or another flat object will work to pry loose soil that has become attached to a surface. Because control samples are typically bigger, bigger equipment, like a garden shovel, must be used. Typically, only the surface of the earth is tested while taking a soil sample.
It is important to ensure that the samples are allowed to dry before collecting because moist samples will still allow additional biological material to be altered, modifying the sample’s overall makeup. You can put dry samples in plastic vials, cartons, and other leak-proof containers. They are chilled beforehand to prevent ongoing microbial activity related to samples taken from the moist region.
Ground penetrating radar
When it comes to forensic geology, the main application of ground-penetrating radar equipment is to locate buried bodies. This tool has proven to be especially helpful in finding missing persons. By identifying a general location where the body is buried, you can improve the retrieval of the body while also speeding up the excavation process. Studies carried out with this gadget reveal information about its capacity to find specific geometries as well as locations that are forensically and historically relevant. This technique uses a transmittance signal to reflect signals off of objects in the ground that have various electrical characteristics. The actual gadget is made up of a radio transmitter and receiver that are connected to ground-based antennas.