Environmental magnetism of Küçükçekmece Lagoon: Paleoenvironmental changes for the last 3900 years

Özlem Makaroglu

Makale detayları

Environmental magnetism of Küçükçekmece Lagoon: Paleoenvironmental changes for the last 3900 years

Yazarlar:

Özlem Makaroglu

Yayıncı:

Çanakkale Onsekiz Mart University

Ana Başlıklar:

Geology (Other)

Dergi:

Journal of Advanced Research in Natural and Applied Sciences Vol.9 Issue 3, pp.545-559

Belge Tipi:

Makale

Yayın Tarihi:

9/2023

Belge Dili:

Türkçe

Document ID (Org No.):

2001298704

pISSN:

2757-5195

Anahtar kelimeler:

Özet:

 In this study, magnetic mineralogy, mineral concentration, and grain size of sediments deposited in Küçükçekmece Lagoon, located in the northern shoreline of the Marmara Sea were determined and the paleoenvironmental evolution of the lagoon for the last 3900 years were investigated based on environmental magnetism. For this purpose, high-resolution mineral magnetic analyses including measurements of magnetic susceptibility κLF, remanent magnetizations anhysteretic and isothermal, and thermomagnetic analysis were carried out in three cores KCL12P1, KCL12P2, KCL12P3 taken from 20 and 17 m depths of Küçükçekmece Lagoon. According to mineral magnetic analysis and lithological description, three units units A, B, and C which were deposited in lagoon sediments were determined. Unit A is characterized by low magnetic susceptibility and mostly consists of detritic paramagnetic minerals siderite and low concentration of fine-grained ferrimagnetic minerals magnetite. Unit B is dominated by greigite and characterized by distinctively high magnetic susceptibility and remanent magnetization. Unit C is determined as coarse-grained and high-coercive ferrimagnetic minerals. According to the environmental magnetism of Küçükçekmece Lagoon; unit A deposited under humid climatic condition between the years 3750-3700 BP, 3600-3350 BP, 3240-1800 BP, 1240 BP present. Units B and C deposited dry climatic conditions during the years 3883-3750 BP, 3700-3600 BP, 3350-3240 BP, 1800-1240 BP. High greigite concentration in unit B is related to the Marmara seawater intrusion onto fresh-water sediments end of every dry climatic condition between the years of 3780-3750 BP, 3620-3600 BP, 3300-3240 BP, and 1300-1240 BP.

 In this study, magnetic mineralogy, mineral concentration, and grain size of sediments deposited in Küçükçekmece Lagoon, located in the northern shoreline of the Marmara Sea were determined and the paleoenvironmental evolution of the lagoon for the last 3900 years were investigated based on environmental magnetism. For this purpose, high-resolution mineral magnetic analyses including measurements of magnetic susceptibility κLF, remanent magnetizations anhysteretic and isothermal, and thermomagnetic analysis were carried out in three cores KCL12P1, KCL12P2, KCL12P3 taken from 20 and 17 m depths of Küçükçekmece Lagoon. According to mineral magnetic analysis and lithological description, three units units A, B, and C which were deposited in lagoon sediments were determined. Unit A is characterized by low magnetic susceptibility and mostly consists of detritic paramagnetic minerals siderite and low concentration of fine-grained ferrimagnetic minerals magnetite. Unit B is dominated by greigite and characterized by distinctively high magnetic susceptibility and remanent magnetization. Unit C is determined as coarse-grained and high-coercive ferrimagnetic minerals. According to the environmental magnetism of Küçükçekmece Lagoon; unit A deposited under humid climatic condition between the years 3750-3700 BP, 3600-3350 BP, 3240-1800 BP, 1240 BP present. Units B and C deposited dry climatic conditions during the years 3883-3750 BP, 3700-3600 BP, 3350-3240 BP, 1800-1240 BP. High greigite concentration in unit B is related to the Marmara seawater intrusion onto fresh-water sediments end of every dry climatic condition between the years of 3780-3750 BP, 3620-3600 BP, 3300-3240 BP, and 1300-1240 BP.

 In this study, magnetic mineralogy, mineral concentration, and grain size of sediments deposited in Küçükçekmece Lagoon, located in the northern shoreline of the Marmara Sea were determined and the paleoenvironmental evolution of the lagoon for the last 3900 years were investigated based on environmental magnetism. For this purpose, high-resolution mineral magnetic analyses including measurements of magnetic susceptibility κLF, remanent magnetizations anhysteretic and isothermal, and thermomagnetic analysis were carried out in three cores KCL12P1, KCL12P2, KCL12P3 taken from 20 and 17 m depths of Küçükçekmece Lagoon. According to mineral magnetic analysis and lithological description, three units units A, B, and C which were deposited in lagoon sediments were determined. Unit A is characterized by low magnetic susceptibility and mostly consists of detritic paramagnetic minerals siderite and low concentration of fine-grained ferrimagnetic minerals magnetite. Unit B is dominated by greigite and characterized by distinctively high magnetic susceptibility and remanent magnetization. Unit C is determined as coarse-grained and high-coercive ferrimagnetic minerals. According to the environmental magnetism of Küçükçekmece Lagoon; unit A deposited under humid climatic condition between the years 3750-3700 BP, 3600-3350 BP, 3240-1800 BP, 1240 BP present. Units B and C deposited dry climatic conditions during the years 3883-3750 BP, 3700-3600 BP, 3350-3240 BP, 1800-1240 BP. High greigite concentration in unit B is related to the Marmara seawater intrusion onto fresh-water sediments end of every dry climatic condition between the years of 3780-3750 BP, 3620-3600 BP, 3300-3240 BP, and 1300-1240 BP.

 Bu çalışmada, günümüzden önce GÖ 3900 yıl boyunca, Marmara Denizinin kuzeyinde yer alan, Küçükçekmece Lagününde depolanan sedimanlarda manyetik mineraloji, mineral yoğunluğu ve tane boyu değişimleri belirlenerek lagünün paleo-ortam koşulları incelenmiştir. Bu amaçla, Küçükçekmece Lagününün 20 ve 17 m. derinliğinden alınan üç adet karotta KCL12P1, KCL12P2, KCL12P3 manyetik duyarlılık κLF, kalıntı mıknatıslanma anhisteretik ve eş -ısıl şiddetleri ve termomanyetik ölçümleri içeren yüksek çözünürlükte manyetik mineral analizleri yapılmıştır. Manyetik mineral analizleri ve litolojik gözlemlere göre, lagün sedimanlarında üç farklı birim birim A, B ve C tanımlanmıştır. Birim A; düşük manyetik duyarlılığa sahip, düşük yoğunlukta ince tane boylu ferrimanyetik manyetit minerallerle birlikte çoğunlukla detritik kökenli paramanyetikler minerallerce siderit baskın bir birimdir. Birim B; yüksek manyetik duyarlılık, kalıntı mıknatıslanma değerleri ve termomanyetik analizlerle kolayca ayırt edilen, demir sülfür greigit içeriği yüksek olan bir birimdir. Birim C ise kaba taneli ve yüksek koersiviteye sahip ferrimanyetik minerallerce baskın bir birim olarak tanımlanmıştır. Küçükçekmece Lagünü-nün çevre manyetizmasına göre, birim A GÖ 3750-3700, 3600-3350, 3240-1800, 1240-günümüz arasında görece yağmurlu; birim B ve C ise GÖ 3883-3750, 3700-3600, 3350-3240, 1800-1240 yılları arasında kurak iklim koşullarının hâkim olduğu dönemlerde oluşmuştur. Lagünde her kurak dönemin sonuna doğru GÖ 3780-3750, 3620-3600, 3300-3240 ve 1300-1240 yılları arasında, greigit mineralinin yoğunlaştığı birim B oluşmuştur. Bu sonuç, nehir girdisinin azalmasıyla beraber, lagünde Marmara Deniz sularının yoğunlaştığı koşulları desteklemektedir.

Makale detayları

Environmental magnetism of Küçükçekmece Lagoon: Paleoenvironmental changes for the last 3900 years

Yazarlar:

Özlem Makaroglu

Yayıncı:

Çanakkale Onsekiz Mart University

Ana Başlıklar:

Geology (Other)

Dergi:

Journal of Advanced Research in Natural and Applied Sciences Vol.9 Issue 3, pp.545-559

Belge Tipi:

Makale

Yayın Tarihi:

9/2023

Belge Dili:

Türkçe

Document ID (Org No.):

2001298704

pISSN:

2757-5195

Environmental magnetism

Holocene

Küçükçekmece Lagoon

Rock magnetism

PaleoclimateÇevre manyetizması

Holosen

Kaya manyetizması

Küçükçekmece Lagünü

Paleoiklim.

Sayı

Makale detayları

Yazarlar: Özlem Makaroglu

Yayıncı: Çanakkale Onsekiz Mart University

Ana Başlıklar: Geology (Other)

Dergi: Journal of Advanced Research in Natural and Applied Sciences Vol.9 Issue 3, pp.545-559

Belge Tipi: Makale

Yayın Tarihi: 9/2023

Belge Dili: Türkçe

Document ID (Org No.): 2001298704

pISSN: 2757-5195

Sayı

Yazarlar:

Özlem Makaroglu

Yayıncı:

Çanakkale Onsekiz Mart University

Ana Başlıklar:

Geology (Other)

Dergi:

Journal of Advanced Research in Natural and Applied Sciences Vol.9 Issue 3, pp.545-559

Belge Tipi:

Makale

Yayın Tarihi:

9/2023

Belge Dili:

Türkçe

Document ID (Org No.):

2001298704

pISSN:

2757-5195