**Figure 2.**

*The map of vent distributions of ACVF (red dots) in relationship with the patters indicating the distributions of volcanic eruptive products from previous research [10]. Numbers refer to locations mentioned in the text.*

*Updates in Volcanology – Transdisciplinary Nature of Volcano Science*

volcanic regions, outlining the geochemical characteristics of the volcanic rocks and linking magma genesis to lithospheric processes. Volcanological research from NE. China are increasingly appearing in the international literature [2–8], however, there volcanic regions are largely unstudied. Among these is the Arxan-Chaihe Volcanic Field (ACVF). Several research outputs have made basic observations of the volcanic history of the region, but a systematic study has only recently been undertaken. Here we report a summary of volcanological observations made in the last six years of research on the ACVF. The aim of the study is to understand the eruptive history, volcanic stratigraphy, eruption styles and associated volcanic

*The general geological map of NE China: The red areas mark the active volcanic fields; the black areas indicate the ceased Cenozoic volcanic fields; also the solid lines in the territory of NE China are the markers of regional* 

In this book chapter, we summarize the field-based observations of two major field

campaigns to provide some basic descriptions of the recognized volcanic products including the most accessible and iconic volcanoes that form the core of the newly established Arxhan UNESCO Global Geopark [9]. We included Tongxin Lake on the northeast corner of ACVF, the Heaven Lake, Tuofengling Lake, Dichi Lake and Yanshan volcanic group (informally identified as the "Triple Vent") (**Figure 2**) to

hazards that may be associated with the ACVF.

*fault systems [1]. VF- volcanic field, VG – Volcanic group.*

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**Figure 1.**

provide evidence of the important role of explosive hydrovolcanism, fissure-fed eruptions, Strombolian-style eruptions and various large-volume lava outpouring to the volcanic architecture of the field. We demonstrate that the Tongxin Lake near Chaihe township (**Figure 2**) is a tuff ring of explosive phreatomagmatic origin that covered an area of at least 13 km2 (**Figure 2**). Eruptions from Tongxin Volcano were probably the most violent in the ACVF indicating the importance of externally-driven explosive hydrovolcanism during the eruptive history of ACVF. In contrast, the youngest known eruption site at Yanshan (C14–2040 +/−75; 1960+/−70; 1990+/−100; 1900+/−70, BP) [11] is a nested scoria and spatter cone with three distinct vents forming a volcanic complex producing scoria-fall, agglutinated and clastogenic lavas. This location demonstrates probably the most common type of volcanic eruption in the ACVF. They are also the most voluminous and the youngest.

The region at and nearby Dichi Lake vent produced the smallest eruptive volumes in ACVF (**Figure 2**). The crater wall of Dichi Lake is composed of lava flows. These were disrupted by an explosive event that left produced angular breccias as a pyroclast ring around the now water-filled crater, best defined as a maar volcano. From Dichi Lake, however, a NE–SW trending fissure exposing a chain of vents gradually builds spatter cones and small scoria cones (**Figure 2**).

The majority of the volcanoes in the western side of the ACVF, closer to Arxan are clearly volcanoes that erupted through magmatic explosion and effusive processes and formed lava spatter cones, spatter ramparts, scoria cones and associated lava flows. Large, elongate craters in this region is filled by water, for example Tuofengling (**Figure 2**). Tuofengling was first interpreted as a scoria cone, but recent field mapping has revealed it is a complex volcanic cone with a basal tuff ring capped by a scoria cone complex. The field-based data presented here provide evidence of one of the largest Pleistocene phreatomagmatic explosive eruptions in the ACVF that formed a maar within a closed intramountain basin (**Figure 2**).
