عنوان
پدید آورنده
موضوع
رده
کتابخانه
محل استقرار
شماره کتابشناسی ملی
شماره
TLpq304133681
زبان اثر
زبان متن نوشتاري يا گفتاري و مانند آن
انگلیسی
عنوان و نام پديدآور
عنوان اصلي
Calcium carbonate dissolution patterns at intermediate water depths of the tropical oceans during the Quaternary
نام عام مواد
[Thesis]
نام نخستين پديدآور
G. A. Haddad
نام ساير پديدآوران
A. W. Droxler
وضعیت نشر و پخش و غیره
نام ناشر، پخش کننده و غيره
Rice University
تاریخ نشرو بخش و غیره
1994
مشخصات ظاهری
نام خاص و کميت اثر
529
یادداشتهای مربوط به پایان نامه ها
جزئيات پايان نامه و نوع درجه آن
Ph.D.
کسي که مدرک را اعطا کرده
Rice University
امتياز متن
1994
یادداشتهای مربوط به خلاصه یا چکیده
متن يادداشت
This study presents mineralogic and stable isotopic records generated for piston cores and Ocean Drilling Program holes recovered from intermediate water depths (500 to 2500 meters) near carbonate platforms around the world. Study areas included the Bahamas (western North Atlantic Ocean), the Nicaragua Rise (Caribbean Sea), the Maldives (north equatorial Indian Ocean), and the Queensland Plateau (southwest Pacific Ocean). Mineralogic data includes percent fine aragonite content, percent fine Mg calcite content, pteropod (aragonitic holoplanktonic gastropods) abundance, percent whole pteropods, and for some cores, percent clear pteropods. Carbonate data were interpreted both in terms of carbonate input from the nearby banks and in terms of seafloor dissolution. Planktic foraminiferal usd\delta\spusdO records were used as the primary chronostratigraphic tool for all sites. Statistical analyses of four metastable CaCO3 dissolution proxies yielded a composite dissolution index (CDI) that displays different dissolution histories for Bahama and Nicaragua Rise sediments over the last 200,000 years. These differences are not predicted by intermediate to deep water nutrient fractionation models (e.g., Boyle, 1988). A good correlation is observed between the Caribbean CDI record (this study) and CaCO3 dissolution and benthic usd\delta\spusdC records from 4641 meters in the Venezuela Basin, Caribbean Sea (Cofer-Shabica, 1987). It is concluded that during the last 200,000 years, variable cross-equatorial flux of Antarctic Intermediate Water has strongly influenced Caribbean carbon chemistry at water depths greater than 1100 meters. The assumption, therefore, that deep Caribbean sediment cores reliably record nutrient and (CO3\sp{=}) variations of average mid-depth Atlantic water may need re-evaluation. Over longer time scales, CaCO3 dissolution records from intermediate water depths near the Bahamas, Maldives, and Queensland Plateau are similar to deep-water dissolution records. Dissolution occurred from thermocline to abyssal depths from 500,000 to 300,000 years ago (during the middle Brunhes Chron) and between 1,000,000 and 900,000 years ago revealing that whole-ocean changes in carbonate chemistry have occurred during the Quaternary. Enhanced CaCO3 dissolution may be related to decreased Ca flux to the ocean (decreased glacial weathering) and increased neritic CaCO3 production and accumulation during periods of elevated interglacial sea-level highstands.
موضوع (اسم عام یاعبارت اسمی عام)
موضوع مستند نشده
Earth sciences
موضوع مستند نشده
Geochemistry
موضوع مستند نشده
Geochemistry
موضوع مستند نشده
Geology
موضوع مستند نشده
Geology
موضوع مستند نشده
Paleoecology
نام شخص به منزله سر شناسه - (مسئولیت معنوی درجه اول )
مستند نام اشخاص تاييد نشده
A. W. Droxler
مستند نام اشخاص تاييد نشده
G. A. Haddad
دسترسی و محل الکترونیکی
نام الکترونيکي
مطالعه متن کتاب وضعیت انتشار
فرمت انتشار
p
اطلاعات رکورد کتابشناسی
نوع ماده
[Thesis]
کد کاربرگه
276903
اطلاعات دسترسی رکورد
سطح دسترسي
a
تكميل شده
Y
