Global analysis reveals climatic controls on the oxygen isotope composition of cave drip water.

The oxygen isotope composition of speleothems is a widely used proxy for past climate change. Robust use of this proxy depends on understanding the relationship between precipitation and cave drip water δO. Here, we present the first global analysis, based on data from 163 drip sites, from 39 caves on five continents, showing that drip water δO is most similar to the amount-weighted precipitation δO where mean annual temperature (MAT) is < 10 °C.

Hydrological and geochemical responses of fire in a shallow cave system.

The influence of wildfire on surface soil and hydrology has been widely investigated, while its impact on the karst vadose zone is still poorly understood. A moderate to severe experimental fire was conducted on a plot (10 m × 10 m) above the shallow Wildman's Cave at Wombeyan Caves, New South Wales, Australia in May 2016. Continuous sampling of water stable isotopes, inorganic geochemistry and drip rates were conducted from Dec 2014 to May 2017.

An optimized chronology for a stalagmite using seasonal trace element cycles from Shihua Cave, Beijing, North China.

Stalagmites play an important role in paleoclimatic reconstructions from seasonal to orbital time scales as Th-dating can provide an accurate absolute age. Additionally, seasonal trace element and optical layers can provide a precise age. We analyzed the seasonal variability of multiple trace elements on a stalagmite (XMG) in Shihua Cave, Beijing and compared them with results from laminae counting.

The East Asian summer monsoon variability over the last 145 years inferred from the Shihua Cave record, North China.

The precipitation variability associated with the East Asian summer monsoon (EASM) has profound societal implications. Here, we use precisely dated and seasonally-resolved stalagmite oxygen isotope (δO) records from Shihua Cave, North China to reconstruct the EASM variability over the last 145 years. Our record shows a remarkable weakening of the EASM strength since the 1880s, which may be causally linked to the warming of the tropical Pacific and Indian Oceans.

Onset and duration of transitions into Greenland Interstadials 15.2 and 14 in northern China constrained by an annually laminated stalagmite.

The onset and duration of abrupt transitions into Dansgaard-Oeschger (DO) events can be studied in detail in Greenland ice cores given the excellent relative uncertainty of its lamina-counting chronology. For other geological archives, however, the shorter intervals are not determined accurately due to lack of clear annual lamina. Here, we present an oxygen isotope record of a stalagmite with well-developed annual lamina from Xinglong Cave, northern China, covering DO 15 and 14.

Testing the annual nature of speleothem banding.

Speleothem laminae have been postulated to form annually, and this lamina-chronology is widely applied to high-resolution modern and past climate reconstructions. However, this argument has not been directly supported by high resolution dating methods. Here we present contemporary single-lamina (230)Th dating techniques with 2σ precision as good as ±0.