Manuscript Details
Manuscript number QUATINT_2019_4_R2
Title Holocene geomorphic evolution and settlement distribution patterns in the mid- lower Fen River basins, China
Article type Full Length Article
Abstract Holocene geomorphic changes have fundamentally shaped the spatial-temporal distributions of prehistoric and historical settlements in North China. Through intensive field surveys and careful field examination of typical sedimentary sequences, we reconstructed the Late-Pleistocene and Holocene geomorphic history in the two major basins of the mid-lower Fen River, central-south Shanxi, China. Our first-hand data provides crucial information for reconstructing the dynamic relationship between the characteristics of Holocene geomorphic changes and settlement distribution patterns in the two basins from the Neolithic period to the Bronze-Age Xia-Shang Dynasties. In the Taiyuan Basin, due to river downcutting processes from the end of the Late Pleistocene to the Early Holocene, edge of the basin emerged and evolved into tablelands. The elevation of the flat lands atop the tablelands that was significantly above the level of floodwater provided an ideal environment for early settlements. The Holocene geomorphic changes are characterised by continous fluvio-lacustrine aggradation, and the central basin became void of human settlements due to uninhabitable hydrological and gemorphic conditions and especially due to frequent floods. Instead, most settlements were located along the basin, displaying a unique “around-basin” distribution pattern. In the Linfen Basin, following large-scale incision of the main channels and branches of the Fen River during the Late Pleistocene, platform-type plain with deep incised valleys was formed. Similar to the surrounding loess tableland, the central basin became an optimal environment for human activities and settlement construction, forming a “full-basin” like settlement distribution pattern that is distinctively different from the “around-basin” distribution pattern in the Taiyuan basin.
Keywords the mid-lower Fen River basins; geomorphic evolution; prehistoric settlement distribution models; regional cultural sequence; Holocene climate events
Corresponding Author Duowen Mo
Corresponding Author's Laboratory for Earth Surface Processes, Ministry of Education, College of Urban Institution and Environmental Sciences, Peking University
Order of Authors Jianqing Lü, Duowen Mo, Yijie Zhuang, Jiaqi Jiang, Y. Liao, Peng Lu, Xiaolin Ren, Jun Feng
Suggested reviewers Tristram Kidder, Guanghui Dong 1 Holocene geomorphic evolution and settlement distribution patterns in the mid-
2 lower Fen River basins, China
3 Jianqing Lüa, Duowen Moa,*, Yijie Zhuangb, Jiaqi Jianga, Yinan Liaoa, Peng Luc,
4 Xiaolin Rena,d, Jun Fenga
5 a Laboratory for Earth Surface Processes, Ministry of Education, College of Urban and
6 Environmental Sciences, Peking University, Beijing 100871, China
7 b Institute of Archaeology, University College London, London WC1H 0PY, UK
8 c Institute of Geographical Sciences, Henan Academy of Sciences, Zhengzhou 450052,
9 China
10 d Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and
11 Geophysics, Chinese Academy of Sciences, Beijing100029, China
12
13* Corresponding author: Duowen Mo ( [email protected])
14
15 Abstract: Holocene geomorphic changes have fundamentally shaped the spatial-
16 temporal distributions of prehistoric and historical settlements in North China. Through
17 intensive field surveys and careful field examination of typical sedimentary sequences,
18 we reconstructed the Late-Pleistocene and Holocene geomorphic history in the two
19 major basins of the mid-lower Fen River, central-south Shanxi, China. Our first-hand
20 data provides crucial information for reconstructing the dynamic relationship between
21 the characteristics of Holocene geomorphic changes and settlement distribution
22 patterns in the two basins from the Neolithic period to the Bronze-Age Xia-Shang
23 Dynasties. In the Taiyuan Basin, due to river downcutting processes from the end of
24 the Late Pleistocene to the Early Holocene, edge of the basin emerged and evolved into
25 tablelands. The elevation of the flat lands atop the tablelands that was significantly
26 above the level of floodwater provided an ideal environment for early settlements. The
27 Holocene geomorphic changes are characterised by continous fluvio-lacustrine
28 aggradation, and the central basin became void of human settlements due to
29 uninhabitable hydrological and gemorphic conditions and especially due to frequent
30 floods. Instead, most settlements were located along the basin, displaying a unique 31 “around-basin” distribution pattern. In the Linfen Basin, following large-scale incision
32 of the main channels and branches of the Fen River during the Late Pleistocene,
33 platform-type plain with deep incised valleys was formed. Similar to the surrounding
34 loess tableland, the central basin became an optimal environment for human activities
35 and settlement construction, forming a “full-basin” like settlement distribution pattern
36 that is distinctively different from the “around-basin” distribution pattern in the Taiyuan
37 basin.
38
39 Keywords: the mid-lower Fen River basins; geomorphic evolution; prehistoric
40 settlement distribution models; regional cultural sequence; Holocene climate events
41
42 1. Introduction
43 Characteristics of historic human activities are closely related to local and regional
44 geomorphic changes. The spatial-temporal distribution pattern of ancient settlements is
45 particularly influenced by geomorphic changes as demonstrated by many recent studies
46(Despriée et al., 2011; Woodward and Huckleberry, 2011; Macklin and Lwin, 2015;
47 Ollivier et al., 2016). Typically, these new geoarchaeological investigations in different
48 regions worldwide have revealed rhythms of long-term geomorphic changes and how
49 they influenced ebb and flow of ancient cultures. During the flood-prone periods of the
50 Tensas Basin in the lower Mississippi River, the ancient inhabitants were forced out of
51 the basin and migrated to the higher peripheries of the basin. They only made a return
52 to the lowlands when the geomorphic process of floods became less active (Kidder,
53 2006; Kidder et al., 2008). At the Kerma culture region of the Upper Nubia, river valley
54 bottoms became uninhabitable as active alluvial activities of several branches of the
55 Nile transformed the alluvial plain into a swampy area before ~7.3 ka BP. The
56 contemporaneous communities sought other optimal places than river valleys for
57 occupation and other economic activities (Honegger and Williams, 2015). Perhaps a
58 more telling and indeed more exciting example comes from recent geological and
59 geomorphic investigations in the Indus valley, which provide new evidence to the long-
60 standing debate of what caused the ‘collapse’ of the Indus Civilization. Giosan et al. 61 (2012) provide important geomorphic evidence for the so-called eastern migration of
62 Harappan settlements. Whilst their research is focused on a broad-brush reconstruction
63 of culture-geomorphic dynamics, other recent studies provide complementary, micro-
64 scale evidence on human adaptations to climate changes. For instance, Singh et al.
65 (2017) have shown that stable hydrology and landform enabled the Indus urban
66 settlements to be situated and utilize resources next to a paleochannel located between
67 the Indus River and Ganges-Yamuna River. A particular significant finding in these
68 aforementioned new studies is that geomorphic changes do not necessarily take place
69 simultaneously with climate change. It is thus crucial to investigate geomorphic
70 changes taken place on the ground and reconstruct their diachronic chronological
71 relationship with climate fluctuations in order to better understand the dynamic
72 relationships among climate, environment and society and especially to better
73 understand the robust adaption and resilience of ancient cultures facing climate
74 fluctuations and environmental vagaries. In China, whilst recent studies also seize upon
75 this new scholarly advancement and have demonstrated that geomorphic evolution was
76 indeed of vital importance to understanding cultural developments in the Yangtze River
77(Liu et al., 2011; Li et al., 2013; Guo et al., 2014) and the Yellow River (Li et al., 2014;
78 Wang et al., 2016; Li et al., 2017; Lu et al., 2017), these studies are mainly focused on
79 long-term climate fluctuations and there is a lack of a longe duree perspective towards
80 the reconstruction of geomorphic evolution and its changing relationships with ancient
81 societies.
82 The mid-lower Fen River basins (Fig.1) experienced pronounced geomorphic
83 changes since the Late Pleistocene period due to a combination of tectonic and climate
84 factors. The fertile soils and rich natural resources fostered economic production and
85 cultural flourishment from the Neolithic to Bronze-Age times. The Taosi City, for
86 instance, was one of the largest urban centers in late-Neolithic North China. The mid-
87 lower Fen River basins present an ideal case to examine long-term dynamic
88 relationships between geomorphic changes and societal development in different sub-
89 regions. We conducted intensive geomorphic surveys in the mid-lower Fen River basins
90 and reconstructed the spatial-temporal distribution patterns of Neolithic and Bronze- 91 Age settlements and their relations with Holocene geomorphic changes. We identified
92 two contrasting settlement distribution patterns, the so-called “around-basin”
93 distribution model in the Taiyuan Basin (TYB) and the “full-basin” distribution model
94 in the Linfen Basin (LFB), respectively, which were both fundamentally constrained
95 by Holocene geomorphic changes. We present how our geomorphic survey was
96 conducted and how the data was collected, and discuss possible reasons responsible for
97 shaping the two contrasting settlement distribution models and their significance to our
98 understanding of regional culture-environmental dynamics.
99
100 2. Regional geological settings and cultural backgrounds
101 Fen River is the second largest tributary in the middle Yellow River. Its midstream
102 flows through the TYB in central Shanxi, and the lower reaches runs through the LFB
103 in south Shanxi (Fig.1). TYB and LFB, divided by the Lingshi Uplift, are surrounded
104 by the Lüliang Mountains, Taihang Mountains and Emei Platform. Moreover, the
105 Chaizhuang Uplift further divides the LFB into south and north sectors.
106 TYB and LFB are parts of the Shanxi Graben System. The initial subsidence phase
107 of the two basins took place in the Pliocene (Wang et al., 1996). During the Early-
108 Middle Pleistocene, large lakes developed in the basins. However, the extensive lakes
109 gradually shrunk and eventually disappeared toward the Late Pleistocene (Li et al.,
110 1998). In the LFB, several fluvio-lacustrine terraces were formed by the Fen River
111 incisions during the Late Quaternary (Hu et al., 2005, 2017).
112 In the TYB, small branches of the Fen River, including the Wenyu River, the
113 Fangshan River, the Wuma River, and the Longfeng River, are originated in the
114 mountain areas on both sides of the basin, before flowing down through the central
115 plain. These small branches and the mainstream of the Fen River form a well-connected
116 water network. In contrast, in the LFB, the mainstream of the Fen River and its tributary
117 branches such as the Honganjian River, the Quting River, the Lao River, the Ju River,
118 the Fu River, and the Kuai River are characterized by downcutting activities, forming
119 deep incised valleys. Situated in the eastern Loess Plateau, the mid-lower Fen River
120 basins have a warm temperate climate. The average annual temperature is 10-13C, and 121 the average annual precipitation is 410-520 mm (Wang et al., 2009). Precipitation is
122 primarily brought in by warm-moist summer monsoon.
123 The mid-lower Fen River connects the Central Plains and the Loess Plateau of
124 China and has played a key role in fostering Neolithic and Bronze-Age cultural
125 developments and prehistoric regional interactions (Li and Hwang, 2013; Lin and
126 Xiang, 2017). To date, the earliest Neolithic culture discovered in the TYB and LFB is
127 the Early Yangshao culture (ca. 7.0-6.0 ka BP). By the 6.0-5.5 ka BP period, the Middle
128 Yangshao culture witnessed remarkable development in both basins, characterized by
129 highly developed painted pottery industry and considerable expansion of Middle
130 Yangshao settlements. The basins were continuously occupied during the succeeding
131 Late Yangshao (5.5-5.0 ka BP) and Early Longshan period (5.0-4.5 ka BP). At around
132 4.5-4.0 ka BP, the Late Longshan culture in the region is marked by widespread use of
133 the pottery li tripod and emergence of early urban centers. The Taosi City (ca. 4.3-3.9
134 ka BP) (He, 2013) rose to an important regional center after a prolonged period of
135 continuous cultural development during the Yangshao period in the region (Department
136 of Archaeology, National Museum of China, 2007). Several decades of excavations at
137 the Taosi City have revealed elite tombs buried with extravagant grave goods, large-
138 sized palatial foundations, and a possible observatory, as well as other important
139 archaeological features (He, 2013). The city was surrounded by a large number of
140 settlements, including some which were specialized in economic production such as
141 stone quarry and stone tool production (Liu et al., 2013). By the Bronze Age Xia (4.0-
142 3.6 ka BP) and Shang (3.6-3.1 ka BP) periods, even though the regional center had
143 shifted to other region, the Fen River basins continued be a vital region for regional
144 cultural development and the exploitation of natural resources by the central state
145 located further south (Liu, 2009).
146
147 3. Research methods
148 3.1. Characterizing Late Pleistocene-Holocene geomorphic changes
149 Well-designed, intensive geomorphic surveys were carried out in 2016 and 2017
150 in the mid-lower Fen River basins. We examined typical strata and sedimentary 151 sequences from a diverse range of geomorphic units. The depositional processes-related
152 natures of these sediments and the geomorphic events they represent were carefully
153 examined during the field surveys. This provides crucial information for stratigraphic
154 correlation and characterization of major geomorphic events in the Fen River and some
155 of its tributaries. We draw schematic plans of Late Pleistocene-Holocene geomorphic
156 changes and their relationships with settlement occupations (Fig.2). Samples were
157 collected from several key sedimentary sequences for OSL (optically stimulated
158 luminescence) dating.
159 3.2. OSL Dating
160 OSL dating was applied to determine the absolute chronologies of some key
161 sedimentary sequences representative of typical geomorphic events. Standard single-
162 aliquot regenerative-dose procedure (Murray and Wintle, 2000, 2003) was performed
163 to measure the equivalent dose (De) at the Ministry of Education Laboratory for Earth
164 Surface Processes, Peking University and the Institute of Geographical Sciences, Henan
165 Academy of Sciences. The uranium, thorium and potassium contents of the samples
166 were measured by neutron-activation-analysis (NAA) at the China Institute of Atomic
167 Energy.
168 3.3. Modelling prehistoric settlement distributions
169 We obtained geographic locations and related details of around 990 Neolithic and
170 Bronze-Age sites based on published information from the “Atlas of Chinese Cultural
171 Relics: Shanxi Volume” (Bureau of Chinese Cultural Relics, 2006) and many other
172 published archaeological reports. These sites were plotted onto a GIS map using
173 ArcGIS10.3 software. In accordance with cultural characteristics and chronological
174 sequences, the historical evolution and spatial distributions of these sites were analyzed
175 and discussed below.
176
177 4. Results and discussion
178 4.1. Dating results
179 Table 1 shows the dating results of the 16 OSL samples collected from the FSH,
180 the WMH, the KS, the LF, the GX and the HM profiles. These dates confirm our field 181 observations that the Late Pleistocene was a crucial period when major geomorphic
182 units or landforms were formed (e.g., the LF, GX and HM locations) and that some of
183 the locations were subjected to further geomorphic changes during the Holocene (e.g.,
184 the FSH, WMH, and KS locations). The age and depth relationships at the WMH and
185 LF locations are of particular significance. The OSL samples were taken from almost
186 the same depth at the two locations, while their chronological results are consistently
187 far apart from each other. This indicates that the two locations experienced different
188 rhythms of geomorphic changes and landscape dynamics since the Late Pleistocene.
189 This difference and its implications to understanding settlement distribution patterns
190 are further discussed below.
191 4.2. Reconstructing geomorphic histories
192 4.2.1. Taiyuan Basin (TYB)
193 In the western TYB, between the eastern piedmont of the Lüliang Mountains and
194 the fluvial plain in the central basin, the tableland is mainly composed of alluvially-
195 reworked loess. Rivers originated in the mountains run through the tableland before
196 joining the Fen River in the plain. At the Fangshan River and the FSH profile (Fig.3a,
197 b), for instance, the lower part of the tableland consists of alluvial sands and gravels,
198 the middle part is a typical Late Pleistocene loess layer embedded with sandy and gravel
199 lenses, and the upper part is another layer of wind-blown loess of the Holocene age.
200 This sedimentary sequence indicates that the Fangshan River plain experienced
201 continuous upward accretion of alluvial sediments during the Late Pleistocene when
202 alluvial fans were formed simultaneously. From the end of the Late Pleistocene to the
203 Early Holocene, the river began a rapid downcutting process and the previous alluvial
204 fans evolved into tablelands. The tablelands were covered by aeolian loess. After
205 continous downcutting of the Fangshan River in the Early Holocene, alluvial
206 aggradation resumed in the Middle Holocene, resulting in the formation of a fill terrace
207 (T1). The terrace surface is 4 m above the present river channel. The lower part of the
208 terrace consists of sand and gravels, while the middle part is a brownish-reddish silty
209 clay layer, with an OSL date of ~4.16±0.28 ka BP. The upper part is a thin Late
210 Holocene loess layer. 211 Compared to the western TYB, the eastern TYB that is situated between the
212 mountains and the Fen River fluvial plain in the central basin is a higher and wider
213 tableland primarily comprised of reworked loess. Typical sedimentary sequences can
214 be seen at the Wuma River and the WMH profile (Fig.3c, d). The Middle Pleistocene
215 loess and the paleosol (paleosol no.S1 in previous studies, Feng et al., 2004) developed
216 during the last interglacial are preserved at the bottom of the tableland at this location.
217 The middle part of the tableland is a Late Pleistocene loess layer contaning sandy and
218 gravel lenses as well as thin silty, reworked loess, and the upper part is a layer of
219 Holocene loess. This sequence suggests that from the end of the Late Pleistocene, the
220 Wuma River began the downcutting process, incising the landscape to up to 20 m deep.
221 After this massive incision process, a fill terrace (T1) emerged during the Middle
222 Holocene. The OSL dating results show that the beginning of the alluvial aggradation
223 took place prior to 5.0 ka BP, followed by river incision at approximate 4.0 ka BP
224(Table 1).
225 The central TYB is a recent fluvial plain. As shown by the sedimentary sequence
226 at a 25 m-deep pit exposed by sand quarrying in the west of the central plain (Fig.4),
227 the sediments here are mainly composed of fluvial gravels embedded with reworked
228 loess. Based on the lithological properties of different layers, this sequence can be
229 divided into six sedimentary units. According to the OSL dating results and the
230 stratigraphic correlation with other profiles in the same basin, layers 1-5 were deposited
231 during the Middle-Late Holocene and layer 6 was deposited during the Late Pleistocene.
232 These results also suggest that alluvial accumulation took place during both the Late
233 Pleistocene and the Middle-Late Holocene, while the transition from the terminal
234 Pleistocene to the Early Holocene was an episode of erosion. As the sediment core no.
235 XD (Fig.1) in northern basin indicates, the change of sedimentation regime from
236 erosion to alluvial aggradation occurred around 6.0 ka BP. The aggradation of the
237 alluvial plain also witnessed the formation of alternating fluvio-lacustrine geomorphic
238 units, which continued to the historical period (Wang, 1997). To sum up, since the Early
239 Holocene, the central basin has been a river-lake fluvial plain, while the piedmont area
240 around the basin edges is a tableland cut through by rivers (Fig. 2a, Fig. 5a). 241 4.2.2. Linfen Basin (LFB)
242 LFB is located in the lower Fen River. Although the central part of the basin is
243 very flat and open, deep incised valleys were formed along the Fen River and its
244 tributaries during the Holocene. The basin as a whole exhibits a platform-type plain
245 landscape. Near the Chaizhuang location of the middle basin is a tectonic uplift area.
246 This tectonic uplift resulted in a raised loess tableland. The lower Fen River basin is
247 partitioned into two parts by the Chaizhuang Uplift. The northern LFB is trending
248 towards north-east direction, while the southern LFB is trending towards east-west
249 direction.
250 The LF profile (Fig.6a) in the northern LFB shows that lacustrine deposits
251 consisting of laminated greyish-green clay were widely distributed in the basin before
252 60.0 ka BP. At about 60.0 ka BP, the downcutting process of the Fen River began,
253 forming a lacustrine fill terrace (T3), which was subsequently mantled by paleosol-
254 loess sequences in the middle-late Late Pleistocene. The rapid downcutting reached the
255 position of terrace T2, which was similarly covered with aeolian sediments including
256 paleosol and loess of the middle-late Late Pleistocene age. The incision gradually
257 reached the bottom of the modern valley. During the Late Holocene, a fill terrace (T1)
258 was formed. The LF profile confirms that the Fen River incision has reached a
259 remarkable depth of around 30 m since 60.0 ka BP, especially during the Late
260 Pleistocene.
261 The GX profile (Fig.6b) is located on the south side of the Chaizhuang Uplift and
262 at the confluence point of the Fu River and the eastern Fen River. Influenced by the
263 Chaizhuang Uplift, from the lacustrine deposits formed in the early Late Pleistocene on
264 the top to the bottom of modern riverbed, the cumulative depth of the downcutting
265 process of the Fen River is over 40 m. During the river incision, a base terrace (T2) and
266 a fill terrace (T1) were developed in the middle Late Pleistocene and the Late Holocene,
267 respectively. The ages of the terrace T2 (Fig.6b) suggest, again, the remarkable depth
268 of the Fen River incision of up to 35 m during the early-middle Late Pleistocene.
269 The sedimentary characteristics of the HM profile (Fig.6c) located in the center of
270 the southern LFB are similar to the two profiles just described. But because it lies in 271 the depression center of the central basin, the incision range of the Fen River at this
272 location is relatively small. In this profile, the height of the terrace T2 is roughly the
273 same as those at the two aforementioned profiles, while the height difference between
274 the terrace T2 and terrace T3 is significantly smaller than that at the GX profile. This
275 confirms that, relative to the basin, the differential uplift of the Chaizhuang Uplift
276 primarily took place in the early-middle Late Pleistocene. During the Late Pleistocene
277 in the lower Fen River, the large scale river incision was related to the regional tectonic
278 uplift.
279 Our examination of the geomorphic changes and chronological patterns at these
280 profiles clearly suggest that, during the rapid downcutting of the Fen River and its
281 tributaries in the LFB in the early-middle Late Pleistocene, the platform-type plain with
282 deep incised valleys were already formed at that time (Fig. 2b, Fig. 5b).
283 4.3. Regional cultural sequence and settlement distributions from Neolithic to Bronze-
284 Age
285 The Early Yangshao culture (7.0-6.0 ka BP) is the earliest Neolithic culture
286 discovered in the TYB and LFB to date. There were two and nine Early-Yangshao
287 settlements, in the two basins, respectively (Fig.7). People resided in semi-subterranean
288 houses during this period. The Early Yangshao communities were primarily reliant on
289 dryland farming (Han, 2010). Typical pottery vessels of this period included the bo
290 bowl, pen basin, ping bottle, guan jar, and so on. Ground stone production tools were
291 dominant, such as axe, adze, chisel, spade, knife, grinding slab and grinding handstone.
292 The pottery vessel sets and stone tools used by the Early Yangshao communities were
293 different in the two basins. The round-bottomed hu jar with folding mouth and the red-
294 topped bo bowl were the most representative types of pottery in the TYB (Tian, 1996).
295 By comparison, the jujube-core-shaped, flat-bottomed ping bottle with small mouth,
296 and the long point-bottomed ping bottle with small mouth became the characteristic
297 pottery types in the LFB (Wei, 2018). By the 6.0-5.5 ka BP period, the Middle
298 Yangshao culture settlements increased significantly in both basins, with the numbers
299 reaching 17 and 143 in the TYB and LFB, respectively. Features of pottery vessels and
300 stone tools tended to be consistent between the two basins. Painted pottery was very 301 prevalent in the archaeological assemblages at local sites. The point-bottomed ping
302 bottle with small overlapping mouth was the most representative type of pottery. By
303 the Late Yangshao phase (5.5-5.0 ka BP), the settlements in TYB saw a small increase,
304 increasing to 35 in number. In the LFB, although there were still 53 settlements, the
305 number evidently smaller compared to the previous phase. Between the two basins,
306 many differences in pottery and stone tools became apparent. In the TYB, the flat-
307 bottomed hu jar with bell-mouth and double-ears became the most representative type
308 of pottery whilst the painted pottery industry was still flourishing. However, the
309 industry suffered a sharp decline in the LFB at the same time, even though some types
310 of pottery similar to those in the previous phase were continuously used (Tian, 1996).
311 During the Early Longshan period (5.0-4.5 ka BP), the settlements number in the TYB
312 decreased slightly to 28, contrary to a sharp increase to 175 in the LFB. The
313 characteristics of the archaeological assemblages in the two basins became consistent
314 again. Distinctive pottery vessels were ding tripods, fu cauldron, dou dish and jia
315 tripods (Tian, 1996). At around 4.5-4.0 ka BP, numbers of the Late Longshan culture
316 settlements reached 82 and 229 in the TYB and LFB, respectively, the highest numbers
317 since the Early Yangshao period in the region. The dryland farming became more
318 developed and intensified (Zhao and He, 2006), and domestic animals (e.g., sheep and
319 cattle.) were also raised at some sites (Brunson et al., 2016). Besides the semi-
320 subterranean houses, above-ground houses and cave buildings also began to be
321 constructed and occupied (Bureau of Chinese Cultural Relics, 2006). More importantly,
322 the Taosi City (He, 2018) in the LFB expanded to an area over 280 ha. It was enclosed
323 by a massive rammed-earth enclosure, inside which were palaces, altar and observatory,
324 as well as many other archaeological features. Some elaborate objects, such as stone
325 chime bells, crocodile-skin drums, jade objects and a few bronze vessels, were also
326 unearthed from the site. These discoveries suggested the formation of a regional state-
327 like entity around the Taosi City. After 4.0 ka BP, during the Bronze-Age Xia-Shang
328 periods, economic industry and agriculture further developed, and the use of bronze
329 vessels became increasingly popular. However, in both basins, settlement numbers
330 decreased, and the regional population as well as the level of social prosperity declined. 331 In the Neolithic and the early historic periods, regional population and settlement
332 numbers grew simultaneously together with social development, cultural exchange and
333 technical innovation. During the Late Longshan period (Fig.7a, b, c), the rapid growth
334 in settlement numbers in both the TYB and LFB might have been related to the
335 emerging trans-Eurasia culture exchange since the late fifth millennium BP (Spengler
336 et al., 2014; Dong et al., 2017). The Fen River basins was a key area of this increasingly
337 connected transcontinental network. Domesticated sheep, arriving into central China
338 via the steppe corridor, for instance, had occurred at the Taosi site (Brunson et al., 2016).
339 This supplementary subsistence strategy of sheep husbandry might have facilitated
340 humans to better adapt in their expanding catchments and territories, especially to
341 mountainous areas. Fig.7a also shows that two episodes of decreases in regional
342 settlements occurred during the Late Yangshao period after 5.5 ka BP and in the
343 Bronze-Age Xia-Shang Dynasties after 4.0 ka BP, although the inconsistent changes of
344 the settlement numbers in the TYB and LFB were also observed from the previous
345 phase (Fig.7b, c). Our surveys show no clear alterations in the regional geomorphic
346 process in this regions during these two periods. However, on a broader scale, these
347 two episodes of settlement reduction coincided with two Holocene climatic events
348 when climates were deteriorating- the “Holocene Event 4” and the “Holocene Event 3”
349(Bond et al., 1997; Wang et al., 2005), which might have caused or linked to the drier
350 and cooler climate in the mid-lower Fen River after 5.5 ka BP (Lü and Zhang, 2008;
351 Chen et al., 2015; Goldsmith et al., 2017) and 4.0 ka BP (Liu and Feng, 2012; Dong et
352 al., 2013a ; Sun and Feng, 2013; Dong et al., 2018). Specifically, the declining land
353 carrying capacity would have led to the population outflow from the LFB beginning
354 from the Late Yangshao period. This demographic and social changes from the Middle
355 Yangshao to Late Yangshao in the LFB are similar to the contemporary transition in
356 the Central Plains (Jia et al., 2008; Drennan and Dai, 2010). In contrast, the TYB may
357 have become a more attractive area for population migration due to its improved
358 landform and ecological conditions. This improvement is evidenced by the slight
359 growth of settlements number in the basin, a situation similar to the contemporary
360 changes observed in the south-central Inner Mongolia (Xu, 2010; Liu et al., 2016) and 361 the Gansu-Qinghai District regions (Dong et al., 2013b).
362 The drought triggered by dramatic climatic transition at ~4.0 ka BP might have
363 severely affected the dryland farming in North China (An et al., 2003; Wu and Liu,
364 2004) with dramatic demographic and social consequences. Our survey and data
365 synthesis thus provide solid evidence to show that, whilst geomorphic characteristics
366 might remain stable, the Holocene climate might experience more frequent fluctuations,
367 causing significant impact on regional settlement distributions.
368 4.4. Relationships between the settlements distribution models and the geomorphic
369 histories
370 In the TYB and LFB, the spatial distributions of Neolithic and Bronze-Age
371 settlements were evidently different from each other. The distribution densities also
372 vary on different landforms. In the TYB, most ancient settlements were located on the
373 loess tablelands between the piedmont and the central plain, and a few settlements also
374 situated on the river valleys of low mountains area. No settlements can be found in the
375 central plain. These show a distinctive “around-basin” distribution model (Fig.2a and
376 Fig.7a). In the LFB, a large number of settlements were distributed on the loess
377 tablelands in front of the mountains as well as the platform-type plain in the central
378 basin. Only a minority of settlements were found in the river valleys of low mountains.
379 These two distributional characteristics show a “full-basin” distribution model. These
380 two contrasting spatial distribution models of ancient settlements in the TYB and LFB
381 reconstructed by our geomorphic evidence are closely related to the differences in the
382 geomorphic histories and characteristics of the two basins.
383 In the TYB, during the Late Pleistocene, large-scale alluvial aggradation in the
384 peripheral piedmont of the basin led to deposition of thick reworked loess with
385 embedded sand and gravels. From the terminal Pleistocene to the beginning of the
386 Holocene, following the massive incisions of the Fen River and its tributaries, the
387 piedmont zone evolved into an alluvial tableland, which was capped by several meters
388 of Holocene aeolian loess. During the Holocene, the tableland surface was constantly
389 above flood levels, which was advantageous for economic production and settlement
390 occupation to take place on it. The plain in the central basin was low and flat, and the 391 Fen River and its tributaries migrated frequently. Since 6.0 ka BP, the plain experienced
392 an aggradation of alluvial sediments and floods became more frequent consequently. In
393 the central basin, it was therefore not suitable for habitation for a long period of time.
394 In the LFB, the Fen River and its tributaries had begun to incise as early as before
395 60.0 ka BP. Most areas in the central basin, formerly occupied by lakes, evolved into
396 the platform-type plain that was mantled by aeolian deposits accumulated since the
397 middle Late Pleistocene. During the Late Pleistocene, the incision range of the Fen
398 River reached at least 22 m. Throughout the Holocene, in the central basin, the flood
399 levels of the Fen River and its tributaries were much lower than the surface of the
400 platform-type plain. This elevation difference became a conducive factor, encouraging
401 human occupation and intensive economic activities during the Neolithic and Bronze-
402 Age periods.
403 From the Late Pleistocene onwards, between the TYB and LFB, there was over 40
404 km long Lingshi Uplift, which was characterized by a bedrock-gorge landscape in the
405 north. This makes the Fen River course resistant to erosion, blocking the retrogressive
406 erosion process commencing from the LFB. In addition, the long-term intermittent
407 uplift of the Lingshi region might have led to the aggradation of the TYB as the
408 elevation of the local base-level. These were two major reasons for the different
409 evolutionary patterns of regional geomorphic processes between the TYB and LFB
410 sections of the Fen River (Wang et al., 1996).
411
412 5. Conclusions
413 Our survey of the geomorphic histories of the two mid-lower Fen River basins
414 shows that, during the Late Pleistocene, the peripheral piedmont in the TYB formed a
415 thick reworked loess layer with embedded sandy and gravel lens. From the end of the
416 Late Pleistocene to the Early Holocene, mainly because of the impact of rapid climate
417 change, the region evolved into a tableland following the incision of the Fen River
418 tributaries. After slight downcutting from the terminal Late Pleistocene to the Early
419 Holocene, the plain in the central TYB experienced a long period of fluvial aggradation
420 since the Middle Holocene. In the LFB, because of regional tectonic uplift, large-scale 421 retrogressive erosions occurred in the Fen River and its tributaries just before 80.0 ka
422 BP. The platform-type plain developed in the central of the basin, with deep incised
423 valleys and comprised of thick lacustrine deposits which were subsequently mantled by
424 aeolian loess.
425 Although the regional settlements might have been influenced by the Holocene
426 climate fluctuations, such as the “Holocene Event 4” and the “Holocene Event 3”, the
427 different geomorphic histories and characteristics of the two basins were the main
428 reasons for two contrasting settlements distribution models. During the Holocene,
429 around the TYB, the loess tableland surface was always above the flood levels of the
430 Fen River and its tributaries. It was a habitable envrionment for settlement construction
431 and economic activities. The fluvial plain in central basin witnessed fluvio-lacustrine
432 aggradational dynamics during the Middle-Late Holocene and frequently-occurred
433 floods were disadvantageous for long-term human occupation, resulting in the
434 formation of the so-called “around-basin” distribution model. The central LFB
435 developed the platform-type plain with deep incised valleys throughout the Holocene
436 and flood threat was minimal there, leading to the formation of a “full-basin”
437 distribution model.
438
439
440 Acknowledgements
441 The authors are grateful to Xinming Xue and Zhenhua Gao at Shanxi Provincial
442 Institute of Archaeology for the help in the field survey. We also thanks Yuetian Li and
443 Yesong Han from Peking University for the assistance in the OSL dating. This work
444 was supported by the National Natural Science Foundation of China (No. 41171006);
445 the Major Program of National Social Science Foundation of China (No.11&ZD183);
446 the National Key Project of Scientific and Technical Supporting Program of China
447 (No.2013BAK08B02); the Foundation for Distinguished Professors of Henan Province;
448 and the Zhengzhou Research Council for the Origins of Chinese Civilization.
449
450 451 References
452 An, C., Feng, Z., Tang, L., Chen, F., 2003. Environmental Changes and Cultural
453 Transition at 4 cal. ka BP in Central Gansu. Acta Geographica Sinica 58(5),
454 743-748 (in Chinese).
455 Bond, G., Showers, W., Cheseby, M., Lotti, R., Almasi, P., deMenocal, P., Priore, P.,
456 Cullen, H., Hajdas, R., Bonani, G., 1997. A Pervasive Millennial-Scale Cycle
457 in North Atlantic Holocene and Glacial Climates. Science 278(5341), 1257-
458 1266.
459 Brunson, K., He, N., Dai, X., 2016. Sheep, Cattle, and Specialization: New
460 Zooarchaeological Perspectives on the Taosi Longshan. International Journal
461 of Osteoarchaeology 26(3), 460-475.
462 Bureau of Chinese Cultural Relics, 2006. The Atlas of Chinese Cultural Relics: Branch
463 of Shanxi Province. SinoMaps Press, Beijing (in Chinese).
464 Chen, F., Xu, Q., Chen, J., Birks, H.J.B., Liu, J., Zhang, S., Jin, L., An, C., Telford,
465 R.J., Cao, X., Wang, Z., Zhang, X., Selvaraj, K., Lu, H., Li, Y., Zheng, Z.,
466 Wang, H., Zhou, A., Dong, G., Zhang, J., Huang, X., Bloemendal, J., Rao, Z.,
467 2015. East Asian summer monsoon precipitation variability since the last
468 deglaciation. Scientific Reports 5, 11186.
469 Department of Archaeology, National Museum of China, 2007. The Research of
470 Settlements Archaeology in the Yuanqu Basin. Science Press, Beijing (in
471 Chinese).
472 Despriée, J., Voinchet, P., Tissoux, H., Bahain, J.J., Falguères, C., Courcimault, G.,
473 Dépont, J., Moncel, M.H., Robin, S., Arzarello, M., Sala, R., Marquer, L.,
474 Messager, E., Puaud, S., Abdessadok, S., 2011. Lower and Middle
475 Pleistocene human settlements recorded in fluvial deposits of the middle
476 Loire River Basin, Centre Region, France. Quaternary Science Reviews
477 30(11), 1474-1485.
478 Dong, G., Jia, X., Elston, R., Chen, F., Li, S., Wang, L., Cai, L., An, C., 2013a.
479 Spatial and temporal variety of prehistoric human settlement and its
480 influencing factors in the upper Yellow River valley, Qinghai Province, 481 China. Journal of Archaeological Science 40(5), 2538-2546.
482 Dong, G., Wang, L., Cui, Y., Elston, R., Chen, F., 2013b. The spatiotemporal pattern
483 of the Majiayao cultural evolution and its relation to climate change and
484 variety of subsistence strategy during late Neolithic period in Gansu and
485 Qinghai provinces, northwest China. Quaternary International 316, 155-161.
486 Dong, G., Yang, Y., Han, J., Wang, H., Chen, F., 2017. Exploring the history of
487 cultural exchange in prehistoric Eurasia from the perspectives of crop
488 diffusion and consumption. Science China Earth Sciences 60(6), 1110-1123.
489 Dong, J., Shen, C.C., Kong, X., Wu, C.C., Hu, H.M., Ren, H., Wang, Y., 2018. Rapid
490 retreat of the East Asian summer monsoon in the middle Holocene and a
491 millennial weak monsoon interval at 9 ka in northern China. Journal of Asian
492 Earth Sciences 151, 31-39.
493 Drennan, R.D., Dai, X., 2010. Chiefdoms and states in the Yuncheng Basin and the
494 Chifeng region: A comparative analysis of settlement systems in North
495 China. Journal of Anthropological Archaeology 29(4), 455-468.
496 Feng, J., 2016. Reconstruction of geomorphic evolution history of three areas around
497 the middle reaches of Yellow River since the late Pleistocene using OSL
498 dating techniques. Ph.D. Thesis, Peking University, China (in Chinese).
499 Feng, Z.D., Wang, H.B., Olson, C., Pope, G.A., Chen, F.H., Zhang, J.W., An, C.B.,
500 2004. Chronological discord between the last interglacial paleosol (S1) and
501 its parent material in the Chinese Loess Plateau. Quaternary International
502 117(1), 17-26.
503 Giosan, L., Clift, P.D., Macklin, M.G., Fuller, D.Q., Constantinescu, S., Durcan, J.A.,
504 Stevens, T., Duller, G.A.T., Tabrez, A.R., Gangal, K., Adhikari, R., Alizai,
505 A., Filip, F., VanLaningham, S., Syvitski, J.P.M., 2012. Fluvial landscapes of
506 the Harappan civilization. Proceedings of the National Academy of Sciences
507 109(26), E1688-E1694.
508 Goldsmith, Y., Broecker, W.S., Xu, H., Polissar, P.J., Demenocal, P.B., Porat, N.,
509 Lan, J., Cheng, P., Zhou, W., An, Z., 2017. Northward extent of East Asian
510 monsoon covaries with intensity on orbital and millennial timescales. 511 Proceedings of the National Academy of Sciences 114(8), 1817-1821.
512 Guo, Y., Mo, D., Mao, L., Jin, Y., Guo, W., Mudie, P.J., 2014. Settlement distribution
513 and its relationship with environmental changes from the Paleolithic to
514 Shang–Zhou period in Liyang Plain, China. Quaternary International 321,
515 29-36.
516 Han, J.Y., 2010. Study on the Initial Yangshao Culture. Ancient Civilizations 8, 16-35
517 (in Chinese).
518 He, N., 2013. The Longshan Period Site of Taosi in Southern Shanxi Province. In:
519 Underhill, A.P., (Ed.), A Companion to Chinese Archaeology. John Wiley &
520 Sons Ltd, Chichester, West Sussex, PP. 255-277.
521 He, N., 2018. Taosi: An archaeological example of urbanization as a political center
522 in prehistoric China. Archaeological Research in Asia 14, 20-32.
523 Honegger, M., Williams, M., 2015. Human occupations and environmental changes in
524 the Nile valley during the Holocene: The case of Kerma in Upper Nubia
525 (northern Sudan). Quaternary Science Reviews 130, 141-154.
526 Hu, X., Li, Y., Yang, J., 2005.Quaternary paleolake development in the Fen River
527 basin, North China. Geomorphology 65(1), 1-13.
528 Hu, X., Zhou, T., Cai, S., 2017.The episodic geomorphological-sedimentary evolution
529 of different basins in the Fenwei Graben and its tectonic implication. Journal
530 of Geographical Sciences 27(11), 1359-1375.
531 Jia, X., Wang, L., Dong, G.H., Chen, F.H., An, C.B., 2008. Cultural evolution and its
532 environmental force in middle Holocene at Guanzhong-Shanbei-Longdong
533 Region, China. Journal of Lanzhou University (Natural Sciences) 44(6), 8-14
534 (in Chinese).
535 Kidder, T.R., 2006. Climate Change and the Archaic to Woodland Transition (3000-
536 2500 Cal B.P.) in the Mississippi River Basin. American Antiquity 71(2),
537 195-231.
538 Kidder, T.R., Adelsberger, K.A., Arco, L. J., Schilling, T. M., 2008. Basin-scale
539 reconstruction of the geological context of human settlement: an example
540 from the lower Mississippi valley, USA. Quaternary Science Reviews 541 27(11), 1255-1270.
542 Li, F., Wu, L., Zhu, C., Zheng, C., Sun, W., Wang, X., Shao, S., Zhou, Y., He, T., Li,
543 S., 2013. Spatial–temporal distribution and geographic context of Neolithic
544 cultural sites in the Hanjiang River Basin, Southern Shaanxi, China. Journal
545 of Archaeological Science 40(8), 3141-3152.
546 Li, J., Han, L., Zhang, G., Su, Z., Zhao, Y., 2017. Temporal-spatial variations of human
547 settlements in relation to environment change during the Longshan culture and
548 Xia-Shang periods in Shanxi Province, China. Quaternary International 436,
549 129-137.
550 Li, T., Mo, D., Kidder, T., Zhang, Y., Wang, H., Wu, Y., 2014. Holocene environmental
551 change and its influence on the prehistoric culture evolution and the formation
552 of the Taosi site in Linfen basin, Shanxi province, China. Quaternary
553 International 349, 402-408.
554 Li, Y., Yang, J., Xia, Z., Mo, D., 1998. Tectonic geomorphology in the Shanxi Graben
555 System, northern China. Geomorphology 23(1), 77-89.
556 Li, Y.T., Hwang, M.C., 2013. Archaeology of Shanxi During the Yinxu Period. In:
557 Underhill, A.P., (Ed.), A Companion to Chinese Archaeology. John Wiley &
558 Sons Ltd, Chichester, West Sussex, PP. 367-386.
559 Lin, M., Xiang, L., 2017. The origins of metallurgy in China. Antiquity 91(359), 1-6.
560 Liu, F., Feng, Z., 2012. A dramatic climatic transition at ~4000 cal. yr BP and its
561 cultural responses in Chinese cultural domains. The Holocene 22(10), 1181-
562 1197.
563 Liu, L., 2009. State Emergence in Early China. Annual Review of Anthropology 38(1),
564 217-232.
565 Liu, L., Zhai, S.D., Chen, X.C., 2013. Production of Ground Stone Tools at Taosi and
566 Huizui: A Comparison. In: Underhill, A.P., (Ed.), A Companion to Chinese
567 Archaeology. John Wiley & Sons Ltd, Chichester, West Sussex, PP. 278-299.
568 Liu, L., Duncan, N.A., Chen, X., Zhao, H., Ji, P., 2016. Changing patterns of plant-
569 based food production during the Neolithic and early Bronze Age in central-
570 south Inner Mongolia, China: An interdisciplinary approach. Quaternary 571 International 419, 36-53.
572 Liu, T., Chen, Z., Sun, Q., Finlayson, B., 2011. Migration of Neolithic settlements in
573 the Dongting Lake area of the middle Yangtze River basin, China: Lake-level
574 and monsoon climate responses. The Holocene 22(6), 649-657.
575 Lu, H., Zhuo, H., Zhang, W., Wang, S., Zhang, H., Sun, X., Jia, X., Xu, Z., Wang, X.,
576 2017. Earth surface processes and their effects on human behavior in
577 monsoonal China during the Pleistocene-Holocene epochs. Journal of
578 Geographical Sciences 27(11), 1311-1324.
579 Lü, H., Zhang, J., 2008. Neolithic cultural evolution and Holocene climate change in
580 the Guanzhong Basin, Shaanxi, China. Quaternary Sciences 28(6), 1050-1060
581 (in Chinese).
582 Macklin, M. G., Lewin, J., 2015. The rivers of civilization. Quaternary Science
583 Reviews 114, 228-244.
584 Murray, A.S., Wintle, A.G., 2000. Luminescence dating of quartz using and improved
585 single-aliquot regenerative protocol. Radiation Measurements 32(1), 57-73.
586 Murray, A.S., Wintle, A.G., 2003. The single aliquot regenerative dose protocol:
587 potential for improvements in reliability. Radiation Measurements 37(4-5),
588 377-381.
589 Ollivier, V., Fontugne, M., Lyonnet, B., Chataigner, C., 2016. Base level changes,
590 river avulsions and Holocene human settlement dynamics in the Caspian Sea
591 area (middle Kura valley, South Caucasus). Quaternary International 395, 79-
592 94.
593 Singh, A., Thomsen, K. J., Sinha, R., Buylaert, J. P., Carter, A., Mark, D. F., Mason,
594 P.J., Densmore, A. L., Murray, A. S., Jain, M., Paul, D., Gupta, S., 2017.
595 Counter-intuitive influence of Himalayan river morphodynamics on Indus
596 Civilisation urban settlements. Nature Communications 8(1617), 1-14.
597 Spengler, R., Frachetti, M., Doumani, P., Rouse, L., Cerasetti, B., Bullion, E.,
598 Mar'yashev, A., 2014. Early agriculture and crop transmission among Bronze
599 Age mobile pastoralists of Central Eurasia. Proceedings of the Royal Society
600B: Biological Science 281(1783), 20133382. 601 Sun, A., Feng, Z., 2013. Holocene climatic reconstructions from the fossil pollen
602 record at Qigai Nuur in the southern Mongolian Plateau. The Holocene 23
603 (10), 1391-1402.
604 Tian, J.W., 1996. Study on the pattern of Shanxi archaeology culture. In: Institute of
605 Archaeology of Shanxi Province, Chinese Society of Archaeology, Society
606 of Archaeology of Shanxi Province (Eds.), Treatises for the International
607 Symposium on Dingcun Culture and Jin Culture. Shanxi College Associated
608 Press, Taiyuan, Shanxi, pp.126-137 (in Chinese).
609 Wang, M.B., Wang, Y.B., Yang, D.T., Qin, Z.H., Fan, X.H., 2009. The Study on the
610 Integrated Management Planning in the Loess Plateau Area of Shanxi
611 Province, China. Forest Press, Beijing (in Chinese).
612 Wang, N.L., Yang, J.C., Xia, Z.K., Mo, D.W., Li, Y.L., Pan, M., 1996. The Sediment
613 and Tectonic Landform during Cenozoic in the Fen River Drainage Basin.
614 Science Press, Beijing (in Chinese).
615 Wang, L., Yang, Y., Jia, X., 2016. Hydrogeomorphic settings of late Paleolithic and
616 early-mid Neolithic sites in relation to subsistence variation in Gansu and
617 Qinghai Provinces, northwest China. Quaternary International 426, 18-25.
618 Wang, S., 1997.The vicissitudes and silting of ancient Zhao-Yu Lake in Taiyuan
619 Basin. Acta Geographica Sinica 52(3), 262-267 (in Chinese).
620 Wang, Y., Cheng, H., Edwards, R.L., He, Y., Kong, X., An, Z., Wu, J., Kelly, M.J.,
621 Dykoski, C.A., Li, X., 2005. The Holocene Asian Monsoon: Links to Solar
622 Changes and North Atlantic Climate. Science 308(5723), 854-857.
623 Wei, X., 2018. The study on the Dongzhuang Type of the Yangshao Culture. Acta
624 Archaeologica Sinica (3), 275-312 (in Chinese).
625 Woodward, J., Huckleberry, G., 2011. The geoarchaeology of river basin systems: An
626 introduction. Geoarchaeology-an International Journal 26(5), 611-615.
627 Wu, W., Liu, T., 2004. Possible role of the “Holocene Event 3” on the collapse of
628 Neolithic Cultures around the Central Plain of China. Quaternary
629 International 117,153-166.
630 Xu, Y., 2010. A preliminary study of the cultural migration round 5000 BP. Acta 631 Archaeologica Sinica (2), 133-170 (in Chinese).
632 Zhao, Z.J., He, N., 2006. Floatation results from the remains excavated on the Taosi
633 city-site in 2002 and their analysis. Archaeology 5, 77-86 (in Chinese).
634
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662 Figures and captions
663 Fig.1. Map showing the mid-lower Fen River and the locations of profiles, core and
664 regional cross-sections mentioned in the text. 1-FSH, 2-WMH, 3-KS, 4-LF, 5-GX and
665 6-HM. The data of the background map is provided by International Scientific &
666 Technical Data Mirror Site, Computer Network Information Center, Chinese Academy
667 of Sciences. (http://www.gscloud.cn).
668
669 Fig.2. a. Distributions of ancient settlements in the Taiyuan basin in different periods;
670 b. Distributions of ancient settlements in Linfen basin in different periods.
671
672 Fig.3. a. Geomorphic-sedimentary cross-section of the Fangshan River (see Fig.1), b.
673 The profile of FSH (see Fig.1); c. Geomorphic-sedimentary cross-section of the Wuma
674 River (see Fig.1), d. The profile of WMH (see Fig.1).
675
676 Fig.4.The profile of KS (see Fig.1).
677
678 Fig.5. a. Geomorphic-sedimentary cross-section of the A-A’ in the Taiyuan Basin (see
679 Fig.1); b. Geomorphic-sedimentary cross-section of the B-B’ in the Linfen Basin (see
680 Fig.1; the paleosols older than S5 are not included here; revised from Hu et al. (2005)).
681
682 Fig.6. Typical profiles in the Linfen Basin. a-LF, b-GX and c-HM (see Fig.1).
683
684 Fig.7. a. Total settlement numbers in the Taiyuan Basin and Linfen Basin. Settlement
685 numbers (densities) on different landforms in (b) the Taiyuan Basin and (c) Linfen
686 Basin.
687
Table 1 Results of OSL dating from different locations Lab Code (profile) Depth (m) U (ppm) Th (ppm) K (%) Dose rate (Gy/ka) Equivalent dose (Gy) Age (ka) L058 (KS) 25.30 1.60±0.07 13.30±0.36 2.98±0.07 3.74±0.15 117.17±12.94 31.34±3.68 L059 (KS) 11.00 2.35±0.09 15.40±0.40 2.27±0.06 4.07±0.23 7.22±0.06 1.77±0.10 L060 (KS) 0.40 3.00±0.10 16.80±0.44 1.93±0.06 4.54±0.28 4.55±0.13 1.00±0.07 L061 (FSH) 2.00 2.39±0.10 11.70±0.33 1.51±0.05 3.18±0.19 13.21±0.39 4.16±0.28 L063 (WMH) 5.80 2.05±0.09 9.35±0.27 1.92±0.06 2.73±0.11 14.72±1.64 5.39±0.64 L064 (WMH) 0.90 2.11±0.09 7.92±0.25 1.94±0.06 2.76±0.11 10.86±1.81 3.93±0.67 L3518 (HM) 3.45 2.71±0.11 10.70±0.31 1.74±0.06 4.13±0.22 350.00±14.80 84.83±5.79 L3519 (HM) 8.85 2.76±0.11 11.10±0.31 1.64±0.05 3.83±0.21 388.10±23.30 101.44±8.17 L2833 (GX) 7.10 2.78±0.11 11.30±0.32 1.74±0.06 3.07±0.20 136.62±7.25 44.50±3.70* L2834 (GX) 7.20 2.40±0.10 9.71±0.28 1.60±0.05 2.74±0.17 154.96±6.90 56.50±4.40* L2835 (GX) 7.20 2.07±0.09 9.78±0.28 1.52±0.05 2.60±0.16 344.67±15.05 132.80±10.20* L3520 (GX) 2.20 3.79±0.14 13.30±0.37 2.26±0.07 5.10±0.27 291.40±9.20 57.11±3.49 L3521 (GX) 4.45 3.07±0.12 12.30±0.34 2.03±0.06 4.47±0.23 163.50±5.80 36.62±2.31 L3522 (GX) 5.25 2.64±0.10 14.70±0.40 1.91±0.06 4.45±0.24 423.50±11.50 95.23±5.71 L3523 (LF) 8.05 3.09±0.12 12.10±0.34 2.17±0.07 4.54±0.23 299.80±15.50 66.03±4.82 L3524 (LF) 6.00 2.78±0.11 11.40±0.32 1.90±0.06 4.12±0.21 281.90±5.60 68.48±3.81 * Three ages were published by one of the authors of this article (Feng, 2016). Conflict of interest statement
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