Paleomagnetism of the Harrat Rahat Volcanic Field, Kingdom of Saudi Arabia—Geologic Unit Correlations and Geomagnetic Cryptochron Identifications

Professional Paper 1862-H
Jointly published with the Saudi Geological Survey [as Saudi Geological Survey Special Report SGS–SP–2021–1]
By: , and 



Paleomagnetic rock samples were collected from 173 drill sites in the Quaternary alkali basaltic volcanic field of northern Harrat Rahat, Kingdom of Saudi Arabia. Laboratory measurements on these samples established that lava flows and vent complexes—identified and mapped from field characteristics, rock types, and compositions as products of single or temporally close eruptions—typically record single, or very similar, directions of remanent magnetization. Correlations defined through geologic mapping, spatial association, geochemistry, geochronology, and identical mean remanent directions indicate at least 16 brief episodes of temporally clustered eruptions. These episodes had durations of a few centuries or less. Anomalous remanent magnetic directions were found for at least 13 mapped lavas of northern Harrat Rahat, which demonstrate that they were acquired during brief geomagnetic cryptochrons during the Brunhes Normal Polarity Chron. These uncharacteristic directions enhance the opportunity to identify common eruptive episodes, and to better understand and evaluate assessments of eruption ages based on 40Ar/39Ar geochronology. Combining paleomagnetic and regional archaeomagnetic results for the youngest eruptions allows us to evaluate their historical age assignments and, in one case, refute a previously assigned provisional age.

Suggested Citation

Champion, D.E., Downs, D.T., Stelten, M.E., Robinson, J.E., Sisson, T.W., Shawali, J., Hassan, K., and Zahran, H.M., 2023, Paleomagnetism of the Harrat Rahat volcanic field, Kingdom of Saudi Arabia—Geologic unit correlations and geomagnetic cryptochron identifications, chap. H of Sisson, T.W., Calvert, A.T., and Mooney, W.D., eds., Active volcanism on the Arabian Shield—Geology, volcanology, and geophysics of northern Harrat Rahat and vicinity, Kingdom of Saudi Arabia: U.S. Geological Survey Professional Paper 1862 [also released as Saudi Geological Survey Special Report SGS–SP–2021–1], 31 p.,

ISSN: 2330-7102 (online)

ISSN: 1044-9612 (print)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods
  • Results
  • Conclusions
  • Acknowledgments
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Paleomagnetism of the Harrat Rahat volcanic field, Kingdom of Saudi Arabia—Geologic unit correlations and geomagnetic cryptochron identifications
Series title Professional Paper
Series number 1862
Chapter H
DOI 10.3133/pp1862H
Year Published 2023
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Volcano Science Center
Description vi, 31 p.
Country Kingdom of Saudi Arabia
Other Geospatial Harrat Rahat volcanic field
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details