May 22 to May 26 2023

Current Archeological Prospection: Advances for Non-destructive Investigations Workshop 2023
NPS Workshop Data

 

National Park Service

The National Center for Preservation Technology and Training (NCPTT), the Midwest Archeological Center, Wichita State University, and the Friends of NCPTT, are hosting a five-day training workshop: Current Archeological Prospection Advances for Non-Destructive Investigations. In its thirtieth year, the workshop will be held May 22–26, 2023 at the Country Club site (14CO3) in Arkansas City, Kansas.

The workshop began at 8 am on Monday, May 22 and end at 5 pm on Friday, May 26. Although the schedule was weather dependent, the general format will consist of lectures planned in the morning, afternoons dedicated to hands-on fieldwork, and short evening sessions oriented toward other topics like data processing.

Participants were cultural resource managers and specialists from federal, state, and local government; private contractors; professors and students; and international cultural resource personnel with responsibilities concerning the identification, evaluation, and preservation of archeological and other cultural resources.

 

Objective

The workshop was organized to provide a practical introduction to ground-based geophysical and other remote sensing techniques that are commonly used for the purposes of identifying, evaluating, and preserving archeological resources. Among these ground-based methods are magnetometry, ground-penetrating radar, earth resistance, metal detecting, conductivity, and magnetic susceptibility. Other techniques that receive attention include terrestrial and airborne lidar, and aerial color and thermal infrared imaging. Lectures cover theory of operation, survey methods, data processing, and interpretation. Participants also have daily opportunities to gain introductory level, hands-on experience in the field

 

Workshop Site (14CO3)

Once composed of 22 separate Great Bend aspect sites (which generally date between AD 1450 and 1700), Country Club is widely regarded as the ancestral Wichita settlement of Etzanoa, visited by Spanish conquistador Juan de Oñate in 1601. Accounts from the Oñate expedition are tantalizing. Well over a thousand houses clustered among agricultural fields are said to have stretched for miles along what is today known as Walnut River. The site is represented archeologically by several extant earthen mounds, low midden mounds, houses, and storage pits. A recent publication in American Antiquity (Casana et al. 2020) describes the results of a multi sensor UAV survey in one area of the site where a suspected “council circle,” a ceremonial earthwork was documented. Current investigations of the site by Wichita State University have received considerable media attention.

 

LIDAR one meter data at the site with features labeled

Lidar, which stands for Light Detection and Ranging, is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. These light pulses—combined with other data recorded by the airborne system — generate precise, three-dimensional information about the shape of the Earth and its surface characteristics.

A lidar instrument principally consists of a laser, a scanner, and a specialized GPS receiver. Airplanes and helicopters are the most commonly used platforms for acquiring lidar data over broad areas. Two types of lidar are topographic and bathymetric. Topographic lidar typically uses a near-infrared laser to map the land, while bathymetric lidar uses water-penetrating green light to also measure seafloor and riverbed elevations.

Lidar systems allow scientists and mapping professionals to examine both natural and manmade environments with accuracy, precision, and flexibility. NOAA scientists are using lidar to produce more accurate shoreline maps, make digital elevation models for use in geographic information systems, to assist in emergency response operations, and in many other applications.

Magnetic Intensity Data again showing features

Electrical resistance surveys (also called earth resistance or resistivity survey) are one of a number of methods used in archaeological geophysics, as well as in engineering geological investigations. In this type of survey electrical resistance meters are used to detect and map subsurface archaeological features and patterning.

Electrical resistance map of ancient Aphrodisias

Contents

OverviewEdit

Electrical resistance meters can be thought of as similar to the Ohmmeters used to test electrical circuits. Archaeological features can be mapped when they are of higher or lower resistivity than their surroundings. A stone foundation might impede the flow of electricity, while the organic deposits within a midden might conduct electricity more easily than surrounding soils. Although generally used in archaeology for planview mapping, resistance methods also have a limited ability to discriminate depth and create vertical profiles (see Electrical resistivity tomography). Further applications include the measurement of the electrical resistivity of concrete to determinate the corrosion potential in concrete structures. Electrical resistance surveying is one of the most popular geophysical methods thanks to the fact it is a nondestructive and economically favorable investigation.[1]

 

Magnetic Susceptibility with features

 


March 8, 2023

Magnetic Susceptibility

Magnetic susceptibility is a fundamental concept in the field of magnetism that describes the magnetization response of a material to an applied magnetic field. It is a measure of the degree to which a material becomes magnetized in response to an external magnetic field. Magnetic susceptibility has many practical applications, including the detection of minerals, environmental studies, and archaeology.

In this article, we will discuss the concept of magnetic susceptibility in detail, exploring its types, properties, and applications. We will also examine the different techniques and instruments used for measuring magnetic susceptibility and their advantages and limitations. Finally, we will explore some of the cutting-edge research in the field of magnetic susceptibility and its potential for future developments.
What Are Magnetic Susceptibility And Permeability?

Magnetic susceptibility and permeability are two important concepts in magnetism that describe the ability of a material to be magnetized in the presence of an external magnetic field.

Magnetic susceptibility refers to the degree to which a material becomes magnetized in response to an applied magnetic field. It is a dimensionless quantity that measures the ratio of the magnetization of a material to the applied magnetic field. Materials with a positive magnetic susceptibility become magnetized in the same direction as the applied field, while those with a negative susceptibility become magnetized in the opposite direction. To put it simply, M=χvH where M is the Magnetization, H is the magnetic field strength and χv is the volume susceptibility.

Permeability μ links magnetizing field H and magnetic flux density B in a material in the following way B = μH. Relative permeability (μr) can be expressed as the ratio of permeability (μ) and permeability of vacuum (μ0), which is a fundamental constant of nature.

The relative permeability is a dimensionless quantity that is directly linked to magnetic susceptibility where χv = μr-1.

Both magnetic susceptibility and permeability are important parameters for understanding the behavior of magnetic materials, and they are commonly used in the design and analysis of magnetic devices such as transformersmotors, and magnetic storage media.

 

DRONE Heat Map and visible light (Casana et al. 2020) with features

While archaeologists have long understood that thermal and multi-spectral imagery can potentially reveal a wide range of ancient cultural landscape features, only recently have advances in drone and sensor technology enabled us to collect these data at sufficiently high spatial and temporal resolution for archaeological field settings. This paper presents results of a study at the Enfield Shaker Village, New Hampshire (USA), in which we collect a time-series of multi-spectral visible light, near-infrared (NIR), and thermal imagery in order to better understand the optimal contexts and environmental conditions for various sensors. We present new methods to remove noise from imagery and to combine multiple raster datasets in order to improve archaeological feature visibility. Analysis compares results of aerial imaging with ground-penetrating radar and magnetic gradiometry surveys, illustrating the complementary nature of these distinct remote sensing methods. Results demonstrate the value of high-resolution thermal and NIR imagery, as well as of multi-temporal image analysis, for the detection of archaeological features on and below the ground surface, offering an improved set of methods for the integration of these emerging technologies into archaeological field investigations.

Thermal and multi-spectral surveys are able to quickly and efficiently resolve historic anthropogenic features, depending on environmental conditions and the diurnal cycle. With a combination of correct timing and post processing, thermal and multi-spectral imaging can reveal some of the same features detectable via traditional terrestrial geophysics but at a much larger scale. These technologies are rapidly becoming critical tools for archaeological remote sensing. While they may be more limited by environmental restrictions than terrestrial geophysics, their cost effectiveness, ease of use, and efficiency makes these attractive solutions for larger surveys. Limiting factors can be overcome by selecting appropriate dates and times for surveys based on environmental conditions, and hardware limitations can be addressed via post-processing. These tools can fit well into a larger research strategy that incorporates historical records, traditional terrestrial geophysical survey, and excavation for validation and ground truthing.

 

Magnetometry CART responsible for gathering the following data

 

Magnetic Data

An area to the NE of the Workshop study area showing features

 One meter LIDAR with Features

 

 

Electromagnetic induction (EMI) ground truthing recommendations (preliminary).



Three areas were surveyed with EMI, mapping EM conductivity and magnetic susceptibility patterning. Field designations for the data sets presented here are AB, D, and E.
Areas AB and E are staked in the area around the excavation in progress during the Workshop.
The Area AB maps have site grid coordinates.
THE AREA D MAP DOES NOT HAVE SITE GRID COORDINATES, but it is staked on the ground as a separate 20x20m grid. I am waiting for clarification regarding real-world/site grid coordinates.
Area E is the area east of Lord Rd. that you directed me to on the last day of the workshop. I left it staked with yellow tent pegs, and don’t have GPS coordinates at this time

AB condition 3

In this conductivity map (depths up to approximately 1.8m), numerous conductivity highs appear that are not expressed in data isolating shallower depths. This suggests the principal source is a meter or more deep. The depth, size, and patterning are consistent with large pits exposed in the nearby excavation. High conductivity suggests organic enrichment or finer-grained soils, also consistent with pit features. One cluster of these are circled in yellow as an example, but many very similar anomalies appeart throughout. an orange circle indicates a particularly large and high contrast conductivity high. The wandering linear anomaly correlates with vegetation patterning, and is probably not of interest

There appears to be less of interest in the susceptibility data in this are than in conductivity. Patterning is generally rather diffuse, and seems to have more to do with topographic and vegetation features than likely archaeological ones. In general, we would expect features of interest to appear as susceptibility highs. A diffuse area of high susceptibility is indicated by a dashed yellow line. A more discrete susceptibility high is circled within it, with similar but more obscure examples not marked. The strongest signal is ignored, and is probably modern metal

 

 

 

 

 

LORD Road Site with Magnetic Data

 

LORD Road Site with detail Magnetic Data

 

Anomalies of possible interest appear in both the Conductivity and susceptibility data. Depths are below the plow zone, with sources possibly below 1m.

 

Instructors

Course instructors consist of experienced practitioners, representatives of instrument manufacturers, and software developers. This list is subject to change, but we anticipate instructors such as Dr. Jarrod Burks, Ohio Valley Archaeology, Inc.; Dr. Kris Lockyear, University College London; David Wilbourn, DW Consulting; Dr. Larry Conyers, Denver University; Peter Leach, Geophysical Survey Systems, Inc.; Dr. Lewis Somers, Geoscan Research USA; Geoff Jones, Archaeo-Physics, LLC; Dr. Doug Scott, Colorado Mesa University; and Chris Kenney, SPX (Sensors and Software).

 

More maps of the Etzanoa sites from ArcGIS studies since 2014 http://www.normconley.net/normconleynet.htm

September 2023

Norm Conley

http://www.normconley.info