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Re-evaluation of the age model for North Atlantic Ocean Site 982 – arguments for a return to the original chronology
No full textRecently, the veracity of the published chronology for the Pliocene section of North Atlantic Ocean Drilling Program Site 982 was called into question. Here, we examine the robustness of the original age model as well as the proposed age model revision. The proposed revision is predicated on an apparent mis-identification of the depth to the Gauss-Matuyama (G/M) polarity chronozone reversal boundary (2.581 Ma) based on preliminary shipboard paleomagnetic data and offers a new chronology which includes a hiatus between ~3.2 and 3 Ma. However, an even more accurate shore-based, u-channel-derived polarity chronozone stratigraphy for the past ~2.7 Ma supports the shipboard composite stratigraphy and demonstrates that the original estimate of the depth of the G/M reversal in the Site 982 record is correct. Thus, the main justification forwarded to support the revised chronology no longer exists. We demonstrate that the proposed revision results in a pronounced anomaly in sedimentation rates proximal to the proposed hiatus, erroneous assignment of marine-isotope stages in the Site 982 Pliocene benthic stable oxygen isotope stratigraphy, and a markedly worse correlation of proxy records between this site and other regional paleoclimate data. We conclude that the original chronology for Site 982 is a far more accurate age-model than that which arises from the published revision. We strongly recommend the use of the original chronology for all future work at Site 982
Modular, Atroposelective Total Synthesis of Micitide 982
No full textA modular, atroposelective total synthesis of micitide 982 (1) is reported. The feature of this report is the gram-scale C-H biarylation of N-phthaloyl-L-alanine followed by atroposelective Larock macrocyclization. This modular approach allowed the construction of a highly strained atrop-Tyr-Trp cross-linkage with unprecedented atropisomerism, as well as the first total synthesis of micitide 982 (1)
Grain size data from ODP Site 162-982
No full textRecords of grain size data measured on the coarse fraction of sediment samples taken during Ocean Drilling Program Site 982 from the Rockall Plateau. For the studies of the coarse fraction the samples were freeze-dried using a FINN-AQUA (lyvotac GT2). Part of the freeze-dried sample was weighed and then washed on a 63-µm sieve and further separated into 63- to 125-, 125- to 500-, 500- to 1000-, and >1000-µm fractions using an ATM-SONIC-Sifter. The 125- to 500-µm fraction was chosen for particle count procedure
(Table 1) Depth-age points used for initial chronology and adjusted ages of ODP Site 162-982
No full textOcean Drilling Program (ODP) Site 982 in the North Atlantic contains a complete latest Miocene to early Pliocene section that was tuned to the astronomical timescale by correlating the record of gamma ray attenuation (GRA) bulk density to summer insolation at 65°N and the benthic d18O signal to orbital obliquity for the interval from 4.6 to 7.5 Ma. The astronomical tuning of the Site 982 record permits a direct bed-to-bed correlation to the cyclostratigraphy of Messinian sections in the Mediterranean (Krijgsman et al., 1999a, doi:10.1038/23231, 2001, doi:10.1016/S0037-0738(00)00171-8). The benthic d18O signal at Site 982 records a latest Miocene glacial period that lasted from ~6.26 to 5.50 Ma and consisted of 18 glacial-to-interglacial oscillations that were controlled by the 41-kyr cycle of obliquity. Although the intensification of glaciation at 6.26 Ma may have contributed to the restriction of the Mediterranean, it preceded the depositional onset of the lower evaporite unit at 5.96 Ma by some 300 kyr. The transition from Stage TG12 to TG11 at 5.5 Ma marks the end of the latest Miocene glacial period and precedes the Miocene/Pliocene boundary by 170 kyr. Although benthic d18O values are relatively low and d18O of bulk carbonate reaches a minimum at the Miocene/Pliocene boundary at 5.33 Ma, there is no single "event" that would indicate deglaciation and sea level rise as the cause of the reflooding of the Mediterranean. We conclude that glacioeustatic changes alone were not responsible for either the start or end of evaporite deposition during the Messinian, suggesting that tectonic or local climate changes in the Mediterranean region were the dominant cause(s)
Calcareous nannofossils and C37 alkenones at ODP Site 162-982
No full textDuring the late Pliocene (~3 to 2.5 Ma), oceanic records of opal and C37 alkenone accumulation from around the world show a secular shift towards lower values in the high latitudes and higher values in the low and mid latitudes. These shifts are broadly coincident with the intensification of northern hemisphere glaciation and are suggestive of changes in export productivity, with potential implications for Pliocene atmospheric carbon dioxide concentrations. The interpretation of a global latitudinal shift in productivity, however, requires testing because of the potential uncertainties associated with site to site comparisons of records that can be influenced by highly nonlinear processes associated with production, export, and preservation. Here, we assess the inferred Pliocene latitudinal productivity shift interpretation by presenting new records of C37 alkenone accumulation from Ocean Drilling Program (ODP) Site 982 in the North Atlantic and biotic assemblages (calcareous nannoplankton) from this site and ODP Site 846 in the eastern tropical Pacific. Our results corroborate the interpretation of C37 alkenone accumulation as a proxy for gross export productivity at these sites, indicating that large-scale productivity decreases at high latitudes and increases at tropical sites are recorded robustly. We conclude that the intensification of northern hemisphere glaciation during the late Pliocene was associated with a profound reorganisation of ocean biogeochemistry
Grammar [982]
No full textGrammar.
This manuscript is now IO Islamic 2971 in the India Office collections.
[metadata: Otto Loth, A Catalogue of the Arabic Manuscripts in the Library of the India Office, (volume 1), no. 982 here with further notations and hyperlinks].
982.
2971. Size 91/2 in. by 7 in.; foll. 60. Seventeen and more lines in a page.
I.Foll. 1-21. A Commentary ( ممزوج ) on ‘Abd al-ḳâhir Jurjânî’s العوامل (see the preceding no.) by MUḤAMMAD ṢÂDIḲ b. Darwîsh Muḥammad . It is entitled جامع القواعد .
Begins: نحمدك يا من جعلت علم النحو ميزان الاعراب و البناء الخ.
Plainly written in Nasta’lîḳ, by Muḥammad Maudûd b. Rafî’ al-dîn Ḥusainî, who completed it on 8th Muḥarram, 1090, at Ujain (?- فى بلدة الاحين ) .
II. Fol. 22. A poem ascribed to IBN ḤÂJIB (d. A.H. 646), in which all the nouns substantives which are feminine by usage are enumerated, القصيدة التى جمع فيها ابن الحاجب المؤنثات السماعية.
Begins:
نفسى الفداء لسائل وافانى بمسائل فاحت كغصن البان
III. Foll. 23-59. Glosses on Ibn Ḥâjib’s الكافية ( see no. 901) , by an unknown author. Imperfect at the end.
Beginning: الحمد لله رب العالمين .... قال الشيخ ابن الحاجب بسم الله الرحمن الرحيم قلت افتتح كتابه تبركا و اقتداء بكتاب الله تعالى الخ.
Written by different hands. Ends abruptly.
On the last page begins the مختصر الميزان , a treatise on Logic ( see no . 575).
Seal and signature of Charles Boddam, Calcutta, May 1st, 1787
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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