Geologist, geographer and writer in the San Francisco Bay Area.
Iron-rich, marble-sized concretions, formed through interaction with water over millions of years, weather out of the Navajo Sandstone formation in southern Utah. During searches for evidence of water and life on Mars, researchers discovered small metallic concretions that are remarkably similar to those in the Navajo Sandstone.
Two deadly earthquakes rocked northwestern Venezuela on June 24, 2026. In a remarkable sequence, a magnitude 7.2 foreshock was followed 39 seconds later by a magnitude 7.5 mainshock. The region has had many large historical earthquakes, so these events were not especially surprising. However, the high numbers of fatalities and injuries, along with widespread damage, are staggering and tragic.
Spectacular volcanoes form the nine Azores islands, which rise out of the northern Atlantic Ocean hundreds of miles west of Portugal. Volcanic eruptions and large earthquakes are a part of life in the Azores. Recently, I had the good fortune to admire impressive landscapes on two of the islands while hiking along miles of trails in this unique and highly scenic region.
The Andes Mountains encompass one of the largest concentrations of volcanoes on Earth. The Incas built shrines on the highest mountains, most notably on active volcanoes, as ceremonial places for offerings and occasionally for human sacrifices. Ancient Andean beliefs shaped responses to their dynamic environment in diverse and unique ways.
A recent research paper titled “By-product recovery from US metal mines could reduce import reliance for critical minerals”, published by researchers from the Colorado School of Mines, provides fascinating information. If by-product recovery at active mines was widely used, it could make other recently proposed extreme measures for obtaining critical minerals, including deep-sea mining,…
Best wishes to you and your loved ones for happy holidays! This is a post I originally published in December 2021, duplicated now with minor edits. Historians and biblical scholars have recorded many stories and traditions related to the Three Magi and the gifts of gold, frankincense, and myrrh they carried to the baby Jesus. The descriptions, which are reflected in the artwork of the time, are…
On July 30, 2025, a powerful M 8.8 earthquake occurred off the coast of the Kamchatka Peninsula in far eastern Russia. Fortunately, there was only moderate damage from the earthquake shaking and the tsunami associated with the earthquake was weaker than expected. All great earthquakes provide scientists with new and valuable information, along with questions about how our earth operates.
Diamonds form under complex and unusual conditions, and provide valuable insights into the evolutionary history and composition of our planet. The diamond rush that began in the Kimberley region of South Africa in the 1860s transformed the area and has had a major influence on the history and economy of the country.
The Nile River had a central role in ancient Egyptian history–and today, Egypt relies on this water for about 90% of the countries’ supply. However, the Nile River Basin also contains ten other countries. Regional population and economic growth, climate change, and the enormous new Grand Ethiopian Renaissance Dam indicate increased cooperation will be essential to manage the Nile River water…
When major rivers flow through multiple states or countries, and water shortages affect a region, conflicts can develop. The Colorado River supplies essential water to seven US states, plus Mexico. Jordan River water is vital to Israel, Jordan, Lebanon, Syria, and Palestine. Disagreements about water allocations and environmental damage in both river basins will eventually require tough decisions…