isotopes, paleoclimate

Oxygen Isotopes and Paleoclimate

Direct measurements for global temperature only date back to about 1850, so how do we figure out what past climates were like? Once we move beyond the limits of direct measurements, we need to use proxies—preserved physical characteristics of past environments. Oxygen isotopes are the most commonly used paleoproxy to reconstruct long records of past… Continue reading Oxygen Isotopes and Paleoclimate

geochronology, isotopes

Introduction to Geochronology

Have you ever wondered, “How do geologists know how old a rock is?”  Geochronology is the science of determining how old rocks, sediments and fossils are. Whether they formed 4 billion years ago or within the historic record, geologists can employ geochronologic methods to determine either the relative or absolute ages of these materials. Radiometric dating–which measures… Continue reading Introduction to Geochronology