Robert Hebenstreit - Academia.edu (original) (raw)

Papers by Robert Hebenstreit

E&G Quaternary Science Journal

Elevated Quaternary sedimentary complexes in the western foreland of the central mountain ranges ... more Elevated Quaternary sedimentary complexes in the western foreland of the central mountain ranges of Taiwan are called tablelands. Their mostly flat surfaces are deeply incised by fluvial processes. The landforms and the fluvial systems in the Miaoli Tableland are investigated by high-resolution terrain analyses based on different datasets. Sediments are described in 51 outcrops and characterized by grain size composition. The outcrops revealed complete or incomplete sequences of the general scheme from bottom to top: sandy tidal-coastal units overlain by gravel-and cobble-rich fluvial deposits always with a fine-grained silt-rich top cover layer influenced by aeolian deposits. All layers are unconsolidated sediments. Three subtypes of this sequence were identified, with respect to the occurrence of the fluvial deposits. The relation of tectonic and erosional processes including the rework of gravels is discussed. The results reveal a tableland surface much more disaggregated than previously mapped, suggesting that individual tableland segments represent remnants of an inferred palaeotopography. The tableland surfaces have been separated into Sedimentary Highlands (SH-I and SH-II) and Sedimentary Terraces (ST) by geometrical properties. The Alluvial and Coastal Plains (AL) represent broad valley bottoms ("box-shaped valleys") in the dendritic drainage systems below 150 m and the coastal plains. The landforms and predominantly the sediment sequences are discussed in the context of the existing stratigraphical schemes of the Toukoshan Formation and the so far rarely used Lungkang Formation. The latter is recommended as the stratigraphical term for the refined subdivision of the uppermost part of late Quaternary sediments in the Miaoli Tableland.

ABSTRACT The island of Taiwan arose from the orogeny caused by the convergence between two tecton... more ABSTRACT The island of Taiwan arose from the orogeny caused by the convergence between two tectonic plates, so the topography on the island is characterized by lofty mountains. More than ten inter-mountainous basins exist in central Taiwan, and the largest one of these basins is called Puli Basin. Within the Puli Basin, various geomorphic features are observed, which reflect multiple processes successively or simultaneously shaping the landforms in the past. Since the 1930s, numerous studies on these inter-mountainous basins have been carried out to explain the origin and the evolution of the landforms in the Puli Basin. In order to critically review previous models for the basin genesis and to test new hypotheses, geophysical, geomorphological, remote sensing, and geochronological methods were applied. These methods include borehole data, gravity anomaly measurements, reflection seismology, geodesy (global positioning system, GPS), aerial photography, field investigation, geomorphic analyses, radiocarbon (14C) dating, and optically stimulated luminescence (OSL) dating. According to the former studies, five genesis hypotheses of the Puli Basin have been proposed: (i) bedrock down warping, (ii) transtension caused by strike-slip fault, (iii) detachment movement under the basin, (iv) piggy-back basin between two trust faults, and (v) graben resulted from transpression and transtension. Some studies in terms of gravity anomaly and reflection seismology reveal the underground structure and morphology; others, using aerial photography and field investigation infer possible geomorphic deformation resulting from tectonic stress. Based on the geophysical and geomorphic data and features, down warping of the bedrock and overlaying sediments seems plausible for the genesis of the Puli Basin. After the general formation of the Puli Basin, the present-day landforms developed under both fluvial and tectonic influences. Two sets of borehole data show three major different sedimentary phases in the past. The lower sediments were deformed by the tectonic compression, and part of the upper ones were dissected by rivers due to the bedrock uplift triggered by the tectonic compression. Tectonic and fluvial processes, i.e. deposition and incision, gave rise to the formation of tablelands and fluvial terraces. Their material and spatial relations were investigated by the studies applying field investigation and geomorphic analyses. However, their formation time is still not clear within a limited time frame provided by only few radiocarbon and OSL dating results. Therefore, the landform evolution of the Puli Basin can only be inferred by interrelation of geomorphic surfaces and tectonic structures, for the numerical chronology remains unclear. This study will first review and discuss the results from previous studies. Based on a critical review and including new findings, we will present new viewpoints on the geomorphology and the development of the Puli Basin.

Abstract The high mountain range of Taiwan represents a unique isolated high altitude area at the... more Abstract The high mountain range of Taiwan represents a unique isolated high altitude area at the junction of the Eurasian continent and the western Pacific Ocean with elevations up to 3952 m asl. It is presently unglaciated, but various glacial landforms and sediments ...

Quaternary Science Reviews, 2016

Abstract The Weichselian Frankfurt ice marginal position in northeast Germany has been critically... more Abstract The Weichselian Frankfurt ice marginal position in northeast Germany has been critically discussed in the past owing to weak morphological evidence and a lack of clear sedimentological records. This study aims to contribute to this discussion with new geochronological and geomorphological results. Apart from very few cosmogenic exposure ages, the time frame is to date still based on long distance correlation with radiocarbon chronologies. We selected a study site in a key position regarding the classic location of the Frankfurt ice marginal position and the recently described arcuate ridge structures on the Barnim plateau. For the first time we present Optically Stimulated Luminescence (OSL) ages of quartz from glaciofluvial deposits for this Weichselian phase. Our results indicate an advance of the Scandinavian Ice Sheet (SIS) at around 34.1 ± 4.6 ka. This is in agreement with OSL ages from sandur deposits at the Brandenburg ice marginal position located farther south and could also be correlated with the Klintholm advance in Denmark. The subsequent meltdown phase lasted until around 26.3 ± 3.7 ka. During the meltdown phase a minor oscillation of the SIS caused the formation of the recently described arcuate ridges on the Barnim till plain. Recalculated surface exposure ages of glacigenic boulders with an updated global production rate indicate a landscape stabilization phase at around 22.7 ± 1.6 ka, which is in agreement with our ages. A phase of strong aeolian activity has been dated with OSL to 1 ± 0.1 ka; this may have been triggered by human activities that are documented in this region for the medieval period.

Taiwan is a subtropical mountainous island situated at the tropic of cancer in the monsoonal west... more Taiwan is a subtropical mountainous island situated at the tropic of cancer in the monsoonal western Pacific region. Its high mountain ranges are not glaciated at present, but since they reach nearly 4000 m they provided favourable conditions for late Pleistocene and early Holocene glacier advances. Their isolated position may provide useful high altitude paleoclimatic information for comparison with marine and continental climate archives and other glaciated areas in the region. At the beginning of this project, only little was known about former glaciations on the island based on the work of early researchers, but detailed sedimentological or chronological information was missing. This study focuses on a detailed geomorphologic field mapping and the description and analysis of glacial landforms and deposits concerning their geometry, composition and morphostratigraphical correlation. For a chronological constrain, optically stimulated luminescence and rock surface exposure dating with in situ produced cosmogenic 10Be were applied on glacigenic sediments and glacial boulders, respectively, which allows an independent temporal correlation of different geomorphologic evidences. The central Nanhuta Shan massif in NE-Taiwan had the best preserved glacial landforms and thus studies were focused there. Comparative observations were made in Hsueh Shan and in Yushan. The main finding of this study is, that glaciers advanced repeatedly in the Taiwanese mountains during the last glacial cycle. Large scale glacio-erosional landforms indicate a last glacial equilibrium line altitude below 3000 m with a depression of about 1000 m. Although, age control is still poor for this maximum stage a correlation with the marine isotope stage (MIS) 4 is assumed. Independently derived OSL and 10Be exposure ages from different small scale glacial sediments in Nanhuta Shan yielded a reliable timeframe for a Lateglacial to early Holocene stage with two possible sub-stages at 12 - 15 ka and 9.5 ka and ELA depressions of 610 m and 510 m, res [...]

Quaternary International, 2013

Geomorphology, 2015

Abstract Despite more than a 100-year-long research history, timing and position of the last glac... more Abstract Despite more than a 100-year-long research history, timing and position of the last glacial ice margins in the northeast German lowland are still up for debate. The Barnim region, a till plain in the northeast German young morainic landscape, is traversed by the contradictorily discussed Frankfurt ice marginal position. It is located in a key position to reassess the current state of research with help of a geographic information system (GIS) and field methods. A qualitative geomorphological analysis of a high resolution LiDAR digital elevation model (DEM) in the Barnim area uncovers a variety of landforms that were previously not described. The most prominent discovery is a set of about 10 lobe-shaped ridges in the middle Barnim area. Fieldwork and geophysical measurements were carried out to investigate the structure of the ridges. The ridges are 1000–1500 m in length and their widths vary from 10 to 15 km. They are raised some 6–10 m from their surroundings. The Frankfurt ice marginal position can only partially be traced in the DEM. Sedimentological and geophysical investigations indicate that the ridges are composed of glacial till that was deposited on glaciofluvial sediments. Their formation most probably took place during the ice retreat of the Brandenburg phase (W 1B ) and hence represents the W 1F phase in the region.

Quaternary International, 2012

Quaternary International, 2014

At the Hohuan Shan, a mountain massif well above 3400 m in altitude in northern Taiwan, a glacial... more At the Hohuan Shan, a mountain massif well above 3400 m in altitude in northern Taiwan, a glacial deformation till has been observed in the uppermost part of the catchment of the Hohuan River. The sediment sequence above the slate bedrock is evidence of a late Pleistocene to early Holocene glaciation as dated in neighbouring mountain massifs, and is discussed in context with the results from a nearby outcrop with dated Holocene slope sediments.

At the Hohuan Shan, a mountain massif well above 3400 m in altitude in northern Taiwan, a glacial... more At the Hohuan Shan, a mountain massif well above 3400 m in altitude in northern Taiwan, a glacial deformation till has been observed in the uppermost part of the catchment of the Hohuan River. The sediment sequence above the slate bedrock is evidence of a late Pleistocene to early Holocene glaciation as dated in neighbouring mountain massifs, and is discussed in context with the results from a nearby outcrop with dated Holocene slope sediments.

The island of Taiwan arose from the orogeny caused by the convergence between two tectonic plates... more The island of Taiwan arose from the orogeny caused by the convergence between two tectonic plates, so the topography on the island is characterized by lofty mountains. More than ten inter-mountainous basins exist in central Taiwan, and the largest one of these basins is called Puli Basin. Within the Puli Basin, various geomorphic features are observed, which reflect multiple processes successively or simultaneously shaping the landforms in the past. Since the 1930s, numerous studies on these inter-mountainous basins have been carried out to explain the origin and the evolution of the landforms in the Puli Basin. In order to critically review previous models for the basin genesis and to test new hypotheses, geophysical, geomorphological, remote sensing, and geochronological methods were applied. These methods include borehole data, gravity anomaly measurements, reflection seismology, geodesy (global positioning system, GPS), aerial photography, field investigation, geomorphic analyse...

eTopoi. Journal for Ancient Studies, 2012

eTopoi. Journal for …, 2012

eTopoi. Journal for …, 2012

eTopoi. Journal for Ancient Studies, 2012

... incorporated. This information complemented the more detailed HEC-RAS hydrological model. 7 O... more ... incorporated. This information complemented the more detailed HEC-RAS hydrological model. 7 Orengo and Palet 2010. 8 Carmona and Riu 2011. 9 Carmona and Riu 2011. 10 Chow 1959. Page 6. 394 Hector A. Orengo • Several ...

eTopoi. Journal for …, 2012

eTopoi. Journal for …, 2012

... Monografías de Historia Rural 6. Zaragoza: Prensas Universitarias de Zaragoza, 2008, 47–90. A... more ... Monografías de Historia Rural 6. Zaragoza: Prensas Universitarias de Zaragoza, 2008, 47–90. Arnau Garcia, Landscape Archaeology Research Group (GIAP), Catalan Institute of ClassicalArchaeology (ICAC), Plaça Rovellat s/n, 43003 Tarragona, Spain, agar-cia@icac.net ...

eTopoi. Journal for Ancient Studies, 2012

E&G Quaternary Science Journal

Elevated Quaternary sedimentary complexes in the western foreland of the central mountain ranges ... more Elevated Quaternary sedimentary complexes in the western foreland of the central mountain ranges of Taiwan are called tablelands. Their mostly flat surfaces are deeply incised by fluvial processes. The landforms and the fluvial systems in the Miaoli Tableland are investigated by high-resolution terrain analyses based on different datasets. Sediments are described in 51 outcrops and characterized by grain size composition. The outcrops revealed complete or incomplete sequences of the general scheme from bottom to top: sandy tidal-coastal units overlain by gravel-and cobble-rich fluvial deposits always with a fine-grained silt-rich top cover layer influenced by aeolian deposits. All layers are unconsolidated sediments. Three subtypes of this sequence were identified, with respect to the occurrence of the fluvial deposits. The relation of tectonic and erosional processes including the rework of gravels is discussed. The results reveal a tableland surface much more disaggregated than previously mapped, suggesting that individual tableland segments represent remnants of an inferred palaeotopography. The tableland surfaces have been separated into Sedimentary Highlands (SH-I and SH-II) and Sedimentary Terraces (ST) by geometrical properties. The Alluvial and Coastal Plains (AL) represent broad valley bottoms ("box-shaped valleys") in the dendritic drainage systems below 150 m and the coastal plains. The landforms and predominantly the sediment sequences are discussed in the context of the existing stratigraphical schemes of the Toukoshan Formation and the so far rarely used Lungkang Formation. The latter is recommended as the stratigraphical term for the refined subdivision of the uppermost part of late Quaternary sediments in the Miaoli Tableland.

ABSTRACT The island of Taiwan arose from the orogeny caused by the convergence between two tecton... more ABSTRACT The island of Taiwan arose from the orogeny caused by the convergence between two tectonic plates, so the topography on the island is characterized by lofty mountains. More than ten inter-mountainous basins exist in central Taiwan, and the largest one of these basins is called Puli Basin. Within the Puli Basin, various geomorphic features are observed, which reflect multiple processes successively or simultaneously shaping the landforms in the past. Since the 1930s, numerous studies on these inter-mountainous basins have been carried out to explain the origin and the evolution of the landforms in the Puli Basin. In order to critically review previous models for the basin genesis and to test new hypotheses, geophysical, geomorphological, remote sensing, and geochronological methods were applied. These methods include borehole data, gravity anomaly measurements, reflection seismology, geodesy (global positioning system, GPS), aerial photography, field investigation, geomorphic analyses, radiocarbon (14C) dating, and optically stimulated luminescence (OSL) dating. According to the former studies, five genesis hypotheses of the Puli Basin have been proposed: (i) bedrock down warping, (ii) transtension caused by strike-slip fault, (iii) detachment movement under the basin, (iv) piggy-back basin between two trust faults, and (v) graben resulted from transpression and transtension. Some studies in terms of gravity anomaly and reflection seismology reveal the underground structure and morphology; others, using aerial photography and field investigation infer possible geomorphic deformation resulting from tectonic stress. Based on the geophysical and geomorphic data and features, down warping of the bedrock and overlaying sediments seems plausible for the genesis of the Puli Basin. After the general formation of the Puli Basin, the present-day landforms developed under both fluvial and tectonic influences. Two sets of borehole data show three major different sedimentary phases in the past. The lower sediments were deformed by the tectonic compression, and part of the upper ones were dissected by rivers due to the bedrock uplift triggered by the tectonic compression. Tectonic and fluvial processes, i.e. deposition and incision, gave rise to the formation of tablelands and fluvial terraces. Their material and spatial relations were investigated by the studies applying field investigation and geomorphic analyses. However, their formation time is still not clear within a limited time frame provided by only few radiocarbon and OSL dating results. Therefore, the landform evolution of the Puli Basin can only be inferred by interrelation of geomorphic surfaces and tectonic structures, for the numerical chronology remains unclear. This study will first review and discuss the results from previous studies. Based on a critical review and including new findings, we will present new viewpoints on the geomorphology and the development of the Puli Basin.

Abstract The high mountain range of Taiwan represents a unique isolated high altitude area at the... more Abstract The high mountain range of Taiwan represents a unique isolated high altitude area at the junction of the Eurasian continent and the western Pacific Ocean with elevations up to 3952 m asl. It is presently unglaciated, but various glacial landforms and sediments ...

Quaternary Science Reviews, 2016

Abstract The Weichselian Frankfurt ice marginal position in northeast Germany has been critically... more Abstract The Weichselian Frankfurt ice marginal position in northeast Germany has been critically discussed in the past owing to weak morphological evidence and a lack of clear sedimentological records. This study aims to contribute to this discussion with new geochronological and geomorphological results. Apart from very few cosmogenic exposure ages, the time frame is to date still based on long distance correlation with radiocarbon chronologies. We selected a study site in a key position regarding the classic location of the Frankfurt ice marginal position and the recently described arcuate ridge structures on the Barnim plateau. For the first time we present Optically Stimulated Luminescence (OSL) ages of quartz from glaciofluvial deposits for this Weichselian phase. Our results indicate an advance of the Scandinavian Ice Sheet (SIS) at around 34.1 ± 4.6 ka. This is in agreement with OSL ages from sandur deposits at the Brandenburg ice marginal position located farther south and could also be correlated with the Klintholm advance in Denmark. The subsequent meltdown phase lasted until around 26.3 ± 3.7 ka. During the meltdown phase a minor oscillation of the SIS caused the formation of the recently described arcuate ridges on the Barnim till plain. Recalculated surface exposure ages of glacigenic boulders with an updated global production rate indicate a landscape stabilization phase at around 22.7 ± 1.6 ka, which is in agreement with our ages. A phase of strong aeolian activity has been dated with OSL to 1 ± 0.1 ka; this may have been triggered by human activities that are documented in this region for the medieval period.

Taiwan is a subtropical mountainous island situated at the tropic of cancer in the monsoonal west... more Taiwan is a subtropical mountainous island situated at the tropic of cancer in the monsoonal western Pacific region. Its high mountain ranges are not glaciated at present, but since they reach nearly 4000 m they provided favourable conditions for late Pleistocene and early Holocene glacier advances. Their isolated position may provide useful high altitude paleoclimatic information for comparison with marine and continental climate archives and other glaciated areas in the region. At the beginning of this project, only little was known about former glaciations on the island based on the work of early researchers, but detailed sedimentological or chronological information was missing. This study focuses on a detailed geomorphologic field mapping and the description and analysis of glacial landforms and deposits concerning their geometry, composition and morphostratigraphical correlation. For a chronological constrain, optically stimulated luminescence and rock surface exposure dating with in situ produced cosmogenic 10Be were applied on glacigenic sediments and glacial boulders, respectively, which allows an independent temporal correlation of different geomorphologic evidences. The central Nanhuta Shan massif in NE-Taiwan had the best preserved glacial landforms and thus studies were focused there. Comparative observations were made in Hsueh Shan and in Yushan. The main finding of this study is, that glaciers advanced repeatedly in the Taiwanese mountains during the last glacial cycle. Large scale glacio-erosional landforms indicate a last glacial equilibrium line altitude below 3000 m with a depression of about 1000 m. Although, age control is still poor for this maximum stage a correlation with the marine isotope stage (MIS) 4 is assumed. Independently derived OSL and 10Be exposure ages from different small scale glacial sediments in Nanhuta Shan yielded a reliable timeframe for a Lateglacial to early Holocene stage with two possible sub-stages at 12 - 15 ka and 9.5 ka and ELA depressions of 610 m and 510 m, res [...]

Quaternary International, 2013

Geomorphology, 2015

Abstract Despite more than a 100-year-long research history, timing and position of the last glac... more Abstract Despite more than a 100-year-long research history, timing and position of the last glacial ice margins in the northeast German lowland are still up for debate. The Barnim region, a till plain in the northeast German young morainic landscape, is traversed by the contradictorily discussed Frankfurt ice marginal position. It is located in a key position to reassess the current state of research with help of a geographic information system (GIS) and field methods. A qualitative geomorphological analysis of a high resolution LiDAR digital elevation model (DEM) in the Barnim area uncovers a variety of landforms that were previously not described. The most prominent discovery is a set of about 10 lobe-shaped ridges in the middle Barnim area. Fieldwork and geophysical measurements were carried out to investigate the structure of the ridges. The ridges are 1000–1500 m in length and their widths vary from 10 to 15 km. They are raised some 6–10 m from their surroundings. The Frankfurt ice marginal position can only partially be traced in the DEM. Sedimentological and geophysical investigations indicate that the ridges are composed of glacial till that was deposited on glaciofluvial sediments. Their formation most probably took place during the ice retreat of the Brandenburg phase (W 1B ) and hence represents the W 1F phase in the region.

Quaternary International, 2012

Quaternary International, 2014

At the Hohuan Shan, a mountain massif well above 3400 m in altitude in northern Taiwan, a glacial... more At the Hohuan Shan, a mountain massif well above 3400 m in altitude in northern Taiwan, a glacial deformation till has been observed in the uppermost part of the catchment of the Hohuan River. The sediment sequence above the slate bedrock is evidence of a late Pleistocene to early Holocene glaciation as dated in neighbouring mountain massifs, and is discussed in context with the results from a nearby outcrop with dated Holocene slope sediments.

At the Hohuan Shan, a mountain massif well above 3400 m in altitude in northern Taiwan, a glacial... more At the Hohuan Shan, a mountain massif well above 3400 m in altitude in northern Taiwan, a glacial deformation till has been observed in the uppermost part of the catchment of the Hohuan River. The sediment sequence above the slate bedrock is evidence of a late Pleistocene to early Holocene glaciation as dated in neighbouring mountain massifs, and is discussed in context with the results from a nearby outcrop with dated Holocene slope sediments.

The island of Taiwan arose from the orogeny caused by the convergence between two tectonic plates... more The island of Taiwan arose from the orogeny caused by the convergence between two tectonic plates, so the topography on the island is characterized by lofty mountains. More than ten inter-mountainous basins exist in central Taiwan, and the largest one of these basins is called Puli Basin. Within the Puli Basin, various geomorphic features are observed, which reflect multiple processes successively or simultaneously shaping the landforms in the past. Since the 1930s, numerous studies on these inter-mountainous basins have been carried out to explain the origin and the evolution of the landforms in the Puli Basin. In order to critically review previous models for the basin genesis and to test new hypotheses, geophysical, geomorphological, remote sensing, and geochronological methods were applied. These methods include borehole data, gravity anomaly measurements, reflection seismology, geodesy (global positioning system, GPS), aerial photography, field investigation, geomorphic analyse...

eTopoi. Journal for Ancient Studies, 2012

eTopoi. Journal for …, 2012

eTopoi. Journal for …, 2012

eTopoi. Journal for Ancient Studies, 2012

... incorporated. This information complemented the more detailed HEC-RAS hydrological model. 7 O... more ... incorporated. This information complemented the more detailed HEC-RAS hydrological model. 7 Orengo and Palet 2010. 8 Carmona and Riu 2011. 9 Carmona and Riu 2011. 10 Chow 1959. Page 6. 394 Hector A. Orengo • Several ...

eTopoi. Journal for …, 2012

eTopoi. Journal for …, 2012

... Monografías de Historia Rural 6. Zaragoza: Prensas Universitarias de Zaragoza, 2008, 47–90. A... more ... Monografías de Historia Rural 6. Zaragoza: Prensas Universitarias de Zaragoza, 2008, 47–90. Arnau Garcia, Landscape Archaeology Research Group (GIAP), Catalan Institute of ClassicalArchaeology (ICAC), Plaça Rovellat s/n, 43003 Tarragona, Spain, agar-cia@icac.net ...

eTopoi. Journal for Ancient Studies, 2012