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shows the localities of sections with stratigraphy presented in Fig. Drainages to the southwest and west are currently undergoing groundwater sapping, with substantial spring-driven flow found at the current river base level.) Holocene lakes and channels in the Hunshandake and lake extent at selected epochs.

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Step 5: EXTRACT TUBE Before the tube falls out of its own accord, stop excavating around it and gently turn tube to loosen and extract.This process initiated a sudden and irreversible region-wide hydrologic event that exacerbated the desertification of the Hunshandake, resulting in post-Humid Period mass migration of northern China’s Neolithic cultures.The Hunshandake remains arid and is unlikely, even with massive rehabilitation efforts, to revert back to green conditions.Resulting hydrologic regime change negatively impacted water availability and Neolithic cultures.Whereas mid-Holocene drying is commonly attributed to slow insolation reduction and subsequent nonlinear vegetation–atmosphere feedbacks that produce threshold conditions, evidence of trigger events initiating state switching has remained elusive. 4,200 years ago in the Hunshandake Sandy Lands of Inner Mongolia, northern China, associated with groundwater capture by the Xilamulun River.For the first time to our knowledge we present a case of desertification mainly triggered by changes in the hydrological and geomorphological system, associated with climate change at ca. Our research on the human–environment interactions in the Hunshandake suggests Chinese civilization may be rooted in the marginal areas in the north, rather than in the middle reaches of the Yellow River.In the middle-to-late Holocene, Earth’s monsoonal regions experienced catastrophic precipitation decreases that produced green to desert state shifts.Step 1: POSITION Place sharpened end of tube, with styrofoam plug, at target point.-target fine-medium sand with original sedimentary structures -avoiding bioturbation and soils -if possible, sample a thick unit with relatively uniform sediment within a foot radius -sample depth MUST be Step 3: MOISTURE Sample horizon for moisture content using an airtight container, fill completely.Note evidence for ground or vadose water and describe expected water content history of the sampled deposit.Step 4: DOSE RATE Sample for the environmental doserate into a 1-quart ziplock freezer bag.