Sydney Basin
The Sydney Basin (English: Sydney Basin ) is a sedimentary basin on the east coast of New South Wales in Australia , consisting of deposits of the Permian and Triassic there. About 4 million people live in this basin, which is named after the city of Sydney , and is the most densely populated region in Australia. Thousands of Aborigines lived in the Sydney Basin before European settlement and when the Blue Mountains , which border the basin, were overcome by settlers in 1813 , the interior of Australia was settled by Europeans.
The Sydney Basin is part of a larger geological sedimentary basin, the Sydney-Gunnadeh-Bowen Basin. There are significant coal mines in the Sydney Basin, the Bowen Basin has the largest coal deposit in Australia, and large natural gas fields have been discovered in the Gunnedah Basin .
location
The basin extends from Newcastle in the north to Durras Lake on Batemans Bay in the south. From Durras Lake it extends to Ulan near Mudgee , and west to the Blue Mountains . The northern border runs along the Liverpool Range to Muswellbrook .
The Sydney Basin covers an area of 44,000 km² on land, around 5,000 km² are under water off the east coast. About 4 million people live on the 44,000 km² land area of the Sydney Basin, i.e. about a fifth of the 21.3 million inhabitants of Australia. The rest of the total area of Australia of 7,692,030 km² is only very sparsely populated except for a few urban regions.
Early settlement
Aboriginal
Aborigines lived there for thousands of years, leaving about 1,500 known rock carvings in the north of the Sydney Basin and other traces such as clam clusters, tool grinding marks, graves, tree carvings, quarries, fish traps and ocher collecting points. In general, the living conditions for early humans in sedimentary basins were ideal, as there were good conditions for collecting food, drinking water and successful hunting.
When Europeans began to settle in the Sydney Basin in 1788, an estimated 2,000 Aboriginal people were living inland, 1,000 between Parramatta and the Blue Mountains and 1,000 between what is now Liverpool and Campbelltown . There are also estimates that around 5,000 to 8,000 Aborigines lived in the Sydney Basin at the time.
The Aborigines living in the Sydney Basin spoke different languages. There were two Darug language groups , one spoken to the east of Parramatta and between Sydney Harbor and Botany Bay and the other to the west between Hawkesbury and the Blue Mountains. Other language groups were the Dharawal , who was spoken south of Botany Bay to Jervis Bay , and a group north of Sydney Harbor spoke Kuringai.
The Aborigines were hunters and gatherers. They lived on fishing in the Sydney area and, further inland in the Sydney Basin, on possums , kangaroos , edible roots, seeds and berries. Food was cooked over open fires. The religion was associated with the dream time . This idea was shaped with spiritual references to the country through song, dance and dream time stories.
With the first settlement by the Europeans in the Sydney Basin, the population of the Aborigines was pushed back. Illnesses, restricted living spaces and the associated deterioration in hunting and gathering conditions for subsistence, violent clashes with Europeans, which degenerated into open war, further decimated the number of Aborigines. The Darug, the largest group of Aborigines who lived in groups of 50, were forced to a semi-nomadic lifestyle and were pushed into the interior and on the edge of the Sydney Basin by the expanded European population until they were finally only 156 in 1827 People cheating.
First European settlement
On January 18, 1788, the HMS Supply, with British convicts on board, was the first ship in the First Fleet to reach Botany Bay. As Botany Bay proved unsuitable for building a settlement, Port Jackson was ultimately chosen and given the name Sydney. As a result, more convicts were transported to the convict colony in Australia . Five years later, in 1793, the first free settlers arrived in Sydney. When John Hunter , the successor to the first governor Arthur Phillip, arrived on September 7, 1795 , the population in the Sydney Basin had risen to about 4,000 people. Lachlan Macquarie took over the post of governor on December 28, 1809, and after twelve years of reign the European population in the Sydney Basin had grown to 24,000. The Blue Mountains acted like a barrier to entry into the interior of Australia and it was not until 1813 that the Europeans Blaxland, Wentworth and Lawson overcame this obstacle. Two years later the first road was built and about 40 years later a railway line was built.
Sydney expanded and the first suburbs emerged in the 1830s and 1840s to accommodate the immigrants.
Economic history
The early settlers around Sydney who lived in the convict colony of Australia had to provide for their own living in the first few years and were dependent on supplies from Great Britain. First they settled towards Parramatta and former convicts near Hawkesbury on productive soils in the immediate vicinity of the Aborigines. Wool, timber, whales and seals were exported through Port Jackson . The export of wood for shipbuilding and shipbuilding became particularly important, as did seal hunting when the East India Company's monopoly was broken. Along the Parramatta River and the Cook and Georges Rivers, settlement could be advanced both to the west and east. These areas were already settled in 1820 and the land grabbing was pushed towards Annandale , Petersham and Ultimo . Wool became an important export. It was not until the mid-1820s that candles, sugar, beer, pottery, and bricks and masonry stones were produced for domestic use. In 1850 the suburbs of Sydney were opened up by the construction of the railway and in 1880 the infrastructure within Sydney was improved with trams. Industry was now able to develop outside of Sydney, settling in the south and east, and industrialists' houses being built in the west along the railway line and new places such as Strathfield and Summer Hill opened up. Further areas on the Cumberland Plain were developed and places established.
In addition to Sydney, Wollongong and Newcastle developed into economically important places in the Sydney Basin, which are located on the coastline and have a harbor.
In the mid-1920s, the number of Sydney residents rose to more than one million residents. In 1931, around a third of Sydney's workforce became unemployed during the Great Depression. A year later, the prices of agricultural products such as wool rose and the economy, especially the construction industry, continued to develop. After the Second World War , many migrants from Europe came to Sydney and the city grew. Sydney and the surrounding area have become Australia's most important economic metropolis with numerous banks, company headquarters and production facilities.
A convict camp was built in Newcastle in 1801 to exploit the coal deposits there and to extract wood. Newcastle is significant today for coal, copper and steel. It has a large port where the products of the metal industry are shipped from the region.
The first settlers came to Wollongong in 1812 to exploit the region's coal reserves. Heavy industry developed there and coal mines shape the area. Because of the nearby coal deposits, which are needed for metal processing, a steel industry was established. The largest steel mill in Australia, that of BlueScope Steel, is located in Wollongong .
Furthermore, agricultural products and the tourism industry in the Sydney Basin are of great economic importance to Australia.
Most of the raw materials in the Sydney Basin are exported, especially to China, which is why economic difficulties develop in this region when the global economy declines.
Landscapes
The Sydney Basin is characterized by different landscapes. The largest landscapes are the Cumberland Plain , the Blue Mountain Plateau , Hornsby Plateau and Woronora Plateau .
Cumberland Plain
The Cumberland Plain is part of Greater Western Sydney and extends 10 km north of Windsor to Picton in the south and along the Parramatta River to inner western Sydney.
The plateau was formed by faults and shaped by rivers. The plain is drained by the meandering rivers of the Hawkesbury River and the Parramatta River. The Cooks River partially flows through this area. On average, the hilly plain is at a height of 30 meters; the highest elevations reach 60 meters and the lowest hardly 10 meters above sea level.
When the European settlers arrived, around 30 percent of the Cumberland Plain was forested; today, only a small proportion of it is forested and is largely characterized by agricultural use.
Blue Mountain Plateau
The Blue Mountains Plateau rises abruptly from the Cumberland Plain on the north-south running Lapstone Monocline from a height of 150 meters near Glenbrook to the Kurrajong Heights at 570 meters above sea level. The deep gorges of the plateau offer sweeping views of the almost horizontal layers of Hawkesbury Sandstone , overlaid by remains of the Triassic Wianamatta Group .
Hornsby Plateau
Along the north-western border is the Hornsby Plateau , which is a little less than 300 meters high on average. It is somewhat blurredly separated from the Blue Mountains plateau by the gorge of the Colo River . In the southeast, the plateau separates from the Cumberland Plain along the clay deposits and extends from near Cattai to Botany Bay. The plateau has an average height of 200 to 220 meters; the river valleys form gorges 80 to 100 meters deep. There are no deep gorges of more than 100 meters. The highest point of the Hornsby Plateau is at Cowan . The landscape is dominated by the Hawkesbury sandstone and the hills are often covered by the Wianamatta Group shale . About 10% of the landscape is populated, 14.6% is used for agriculture, 4.8% is open landscape and the rest is from the parks like Ku-ring-gai-Chase National Park , Murramurra National Park , Muogamarra Nature Reserve and Berowra Valley Regional Park occupied. There are large bush landscapes and protected plants and animals in the parks.
Woronora plateau
The approximately 1,000 km² Woronora Plateau is located in the southwest of Sydney and is part of the Sydney Basin. It is a sandstone plateau made from Hawkesbury sandstone. The Woronora River flows through this plateau and flows into the Georges River . About 1,000 Aboriginal rock carvings have been found on this plateau .
91 percent of Sydney's drinking water is obtained from this area.
climate
The climate in the Sydney Basin is known as warm. The winters in the Blue Mountains are long and mild and the average daytime temperatures on the coast are a little less than 26 ° C in summer and a little more than 29 ° C on the Cumberland Plain. The average rainfall varies around 1,210 mm and the heaviest rainfall occurs in autumn. Less than 670 mm falls annually in the hinterland. On the Woronora Plateau, the summers are warmer and the winters a little colder than in the other regions.
In the Ice Age about 120,000 to 130,000 years ago, the sea was about 5 meters higher. Between 31,000 and 34,000 years ago the temperature was around 3 ° C lower than it is today and 15,000 years ago the temperatures rose; the glaciers melted and with the beginning of the Holocene 10,000 years ago the temperatures were like today.
geology
The geology of the Sydney Basin is the result of sedimentation , volcanoes and earth movements.
The Sydney Basin is adjacent to the Bowen Basin ; to the south and west it is bounded by the mountains of metamorphic and granitic rocks of the Lachlan Fold Belt . To the north is the Hunter Valley and the New England Fold Belt , while to the northwest is the Gunnedah Basin and to the east is the continental shelf .
Jurassic, Mesozoic, Cenozoic
During the Jurassic , Mesozoic and Cenozoic there was volcanic activity in the Sydney Basin.
Minor igneous activity occurred in the early Jurassic 210 million years ago, in the late Mesozoic 100 to 90 million years ago, and in the Cenozoic 65 million years ago.
In the Jura, volcanic diatrems (volcanic chimneys filled with rock) formed, which ejected volcanic and sedimentary breccias and basalt. Later they partially filled with water, the maars . There are over 30 in the Sydney area, but they are little known. The vent near Hornsby in the north-west shows volcanic breccias in a quarry, in which numerous xenolites are embedded. The dolerite occurrence near Parramatta also originated in the early Jurassic .
In the Bondi chimney, which lies along the coastline on Bondi Beach , breccias made of sediments with embedded basalt can be seen. There are also numerous basalt dikes in the Sydney area along the cliffs on the coast and on platforms of the rocks related to the diatrems. You are painting in the east-south-east direction. Other basalt and dolerite gesture entrances are along Long Reef , La Perouse , Hunters Hill and Port Kembla .
Further volcanic activity emerged in the late Mesozoic as basalt dikes along the central coast of New South Wales and Newcastle .
Activities in the Cenozoic included the emergence of isolated basalt feet that form the covers of Mount Bank and Mount Wilson in the Blue Mountains and Peats Ridge on the central New South Wales coasts.
Perm
In the Permian, the stratigraphic formations such as the Dalwood Group and Lower Shoalhaven Group emerged , in which limestone-bound sandstones, slate and conglomerate rocks, lava and volcanic tuffs were formed through deposits .
In the formation of the Greta Coal Measures , sand and shale rocks, conglomerates and coal were formed; in the Maitland and Shoalhaven Group , clay and sandstones as well as slate were created. The sediments on the south coast originated from the Gerringong volcanoes and from glacial deposits of the Hunter Valley .
The largest coal deposits in the Sydney Basin originated in the formation of the Illawarra , Tomago and Newcastle Coal Measures as well as sandstones and claystones. Plants were stored and petrified in the conglomerates formed at that time.
The Sydney Basin was formed in the early Permian by a reef made of lime and stored coal. At the end of the Permian, sediments transported in rivers formed deposits and alluvial soils with a corresponding environment formed. The maximum height of the deposit reached 5,000 meters. Around the middle of the Triassic , the land rose and fell dry. The subsequent erosion formed today's environment.
Triad
In the Triassic, quartz-bound sandstones were created in the Narrabeen Group, along with slate and clay stones, and in the conglomerates plants, fish and amphibians were petrified. The rocks of the Narrabeen Group can be viewed at the Three Sisters .
In the Hawkesbury Sandstone formation , high-quartzitic sandstones were deposited, some of which were separated by clay deposits. Hawkesbury sandstone is located to the east and north and west of the Sydney Basin. Hawkesbury sandstone, known as natural stone and stratigraphic formation, emerges on the surface, especially in the Sydney area. This sandstone was quarried during the Victorian era and was widely used to build houses in the city of Sydney.
Thin layers of sandstone are formed in the Mittagong Formation .
The Wianamatta Group was formed from a large deposit delta that stretched from west to east. In this stratigraphic formation, a distinction is made between the Ashfield Group with its clay deposits and clay as well as shale rocks that were formed in a marine environment. Another distinction made by the Wianamatta Group is the formation of the Minchinbury Sandstone , in which sandstones were formed from sand hill islands in the inland lake, and the formation of the Bringelly Shale , in which shale and sandstones were formed from the deposits of meandering rivers flowing west.
Web links
- The Sydney Basin on ga.gov.au
- NSW Department of Primary Industries - Sydney Basin - Geological Overview
- Geology of the Sydney Basin at www.hawkesbury.net.au
Individual evidence
- ^ Development of the Sydney Basin. New South Wales Department of Primary Industries , accessed January 28, 2010
- ↑ Historical traces of the Aborigines in the Sydney Basin , accessed on January 31, 2010
- ↑ a b Information on environment.nsw.gov.au , accessed on January 31, 2010
- ↑ Arthur Phillip: Australia. The establishment of the penal colony. 1st edition, Lamuv, Göttingen 2001
- ↑ Data on thefifthestate.com.au , accessed January 30, 2010
- ↑ Geology of the Sydney Basin at www.hawkesbury.net.au ( Memento of the original from October 24, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed January 31, 2010
- ↑ Geography on hornsby.nsw.gov.au ( Memento of the original from January 25, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed January 31, 2010
- ↑ a b Images of the Aborigines' places on the Woronora Plateau ( Memento of the original from September 3, 2006 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed January 31, 2010
- ↑ a b c The Sydney Basin - Environmental Context ( Memento of the original from March 5, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , at epress.anu.edu.au, accessed January 30, 2010
- ^ David Burgess: Mining to spread across the Woronora Plateau . In: Colong Bulletin . No. 227 , 2007 ( pdf (615KB) ).
- ↑ a b c d The Sydney Basin at australianmuseum.net.au , accessed January 28, 2010
- ^ Australianmuseum.net.au : Sydney Museum. Retrieved January 26, 2012
- ↑ Herbert Chris, Helby Robin: A Guide to the Sydney basin. Geological Survey of New South Wales, Maitland 1980, ISBN 0-7240-1250-8 , p. 582.
Coordinates: 33 ° 57 ′ S , 150 ° 46 ′ E