SHRIMP (Sensitive High Resolution Ion MicroProbe) is an instrument that for decades has used the radioactive decay of uranium into lead to measure geologic time. The accuracy and precision of this instrument has not been seriously reviewed in almost 20 years. This paper compares several dozen SHRIMP ages in our database with more accurate and precise methods to assess SHRIMP accuracy and precision. Analytical and geological complications are addressed to try to improve the method.

Absolute chronological constraints are crucial in Earth and planetary sciences. In recent years, U–Pb dating of carbonates has provided information on the timing of, for example, diagenesis, faulting, or hydrothermalism. These studies have targeted relatively young terrestrial carbonates up to 300 million years old. By dating 3.9 billion-year-old martian carbonates in situ using the U–Pb chronometer, we show that this system is robust in ancient samples that have had a relatively simple history.

Advancements in technology have introduced new techniques to more quickly and cheaply date rocks with little sample preparation. A unique use of this method is to date shales and constrain when these rocks were first deposited. This approach can also time when such sequences were subsequently affected by heat or fluids after they were deposited. This is useful, as the formation of precious-metal-bearing systems or petroleum source rocks is commonly associated with such processes.

This work provides equations allowing the use of minerals with variable concentrations of parent and daughter isotopes as primary standards to correct for elemental fractionation during the analysis by laser ablation inductively coupled plasma mass spectrometry.

The article demonstrates a new technique that can be used to determine the age of calcite crystallisation using the decay of ¹⁷⁶Lu to ¹⁷⁶Hf. The technique is novel because (a) Lu–Hf radiometric dating is rarely applied to calcite and (b) this is the first instance where analysis has been conducted by ablating the sample with a laser beam rather than bulk dissolution. By using laser ablation the original context of the sample is preserved.